2014 Rule Book with 7-7-14 updates
SECTION 1 - PURPOSE AND INTENT
SECTION 2 - GENERAL RULES, REGULATIONS, AND GUIDELINES
SECTION 3 - RACE PROCEDURES, GENERAL KART AND DRIVER SAFETY
SECTION 4 - GENERAL ENGINE RULES AND TECHNICAL PROCEDURES
SECTION 5 – REGISTRATION, POINTS, PENALTIES, AND AWARDS
SECTION 6 - CHASSIS RULES
SECTION 7- GENERAL RULES
SECTION 8- ENGINE TECH GUIDELINES
SECTION 9- CLASS TECHNICAL SPECIFICATIONS
SECTION 1 - PURPOSE AND INTENT
1.0 General Rules and Right to Attend and Compete
A. This Sanctioning Body reserves the right to prohibit the entrance of any person to any
Sanctioned Event at our discretion for any reason, including but not limited to, misconduct
including actions, verbal, physical or otherwise.
B. Prior to the start of an officially sanctioned racing event, we reserve the right to broadcast
the Star Spangled Banner, and offer up a prayer for the safety of our racers. If you find
these rules offensive or objectionable, you have the freedom in this country to not
participate, however we do ask that you respect the opinions and beliefs of your fellow
competitors who choose to participate by remaining silent during the prayer. If you feel the
desire to sing along to the Star Spangled Banner, please feel free. If you cannot, or will not
abide by these regulations, we reserve the right to refuse services to you and any parties
attending the races with you, and further reserve the right to have you removed from the
premises of any racetrack operating under these guidelines. We may at our discretion also
suspend anyone who causes a nuisance at any sanctioned event, for any period of time
including indefinitely.
C. USKRA, LLC will not knowingly discriminate against anyone due to age, race, color,
creed, religious affiliation, or sexual orientation, nor will we knowingly employ anyone
who does.
D. The goals of the USKRA, LLC, Inc. are to provide a family-oriented, safe, and affordable
karting experience for its members and their families.
E. USKRA, LLC has published these rules to give immediate online access to any track that
chooses to use our rules, and we offer to provide guidance at our convenience.
F. Judgments made on anything not covered in the rules will be up to the discretion of the
USKRA, LLC officials, tech inspectors, and/or raceway management without recourse
from any owner, driver, crewmember, or spectator.
G. The rules and regulations set forth and contained herein are designed to provide orderly
and safe racing events and to establish minimum acceptable standards and requirements for
said events. If you have any questions regarding the rules or procedures, please feel free to
E-Mail all inquiries to: MaterSammichMan@GMail.com
H. Track officials reserve the right to refuse entrance to any kart, driver, or any other
person/persons to the pit area, infield, or grand stands.
I. We ask that you please do not use offensive language and profanity! Karting is a family
sport. Please help us to maintain a family-friendly atmosphere of mutual respect.
J. USKRA, LLC and any host track of an officially sanctioned USKRA, LLC event are not
responsible for accidents of any nature, any damages incurred, or any loss of property
while on the premises of any sanctioned event.
K. Kart racing can be dangerous. Safety is of importance to USKRA, LLC, and should always
be the primary concern of all USKRA, LLC members. USKRA, LLC reserves the right to
change the race program or rules at anytime for the improvement of safety in racing. Strict
adherence to the USKRA, LLC rules and guidelines are required at sanctioned events. This
is for your safety and the safety of others. Please do your part in helping USKRA, LLC
make kart racing a safe and enjoyable experience for everyone.
L. Local tracks/ promoting organizations are not expected to run all of the available classes,
and may create their class structure from any of the USKRA, LLC National classes at their
discretion.
SECTION 2 - GENERAL RULES, REGULATIONS, AND GUIDELINES
2.1 General Rules
A. All Members are responsible to know the policies, rules and regulations set forth herein,
and those that may be added at the discretion of USKRA, LLC, Inc.
2.2 Voluntary Association:
A. Involvement with this USKRA, LLC is voluntary. If you register to race you are accepting the
rules.
B. Please read the rules and become familiar with them.
2.3 Spirit and Intent:
A. The spirit and intent of sportsmanlike racing is to race without endangering your fellow
participants. Inadvertent contact is a reality of racing; however if in the judgment of the
flagman a participant is rough-driving other participants intentionally, that participant shall be
subject to penalties. Although USKRA, LLC rules are comprehensive, they may not address
every situation. The Race Director of the event will consider the goals of USKRA, LLC, and
use common sense and the spirit and intent of these rules to make the proper decisions. When a
decision cannot be made at the local level, it shall be addressed to the USKRA, LLC Director
of Racing. In all matters, the USKRA, LLC Director of Racing’s decision is final.
2.4 Policies, Rules and Regulations:
A. The registered competitor; or in the case of a minor, the Legal Guardian of the competitor,
assumes full responsibility for their kart and the conduct of their pit crew, and shall be the sole
spokesperson thereof.
2.5 Assumption of Risk
A. Members assume full responsibility for any and all injuries sustained, property damage, and
including but not limited to death, at any time while at any sanctioned USKRA, LLC event
while on the race premises, or in route to or from said premises. No USKRA, LLC member
will have any claim for expenses or damage against USKRA, LLC or its promoters or officials
regardless of negligence. No insurance of any type is provided by USKRA, LLC on vehicles in
pits or infield. The primary responsibility for the safe condition and operation of a kart rests
with the owner and/or driver. Anyone may inspect the racecourse if or when the Race Director
allows racecourse inspection. By participating you affirm that the racecourse is acceptable for
competition.
2.6 Driver Insurance
A. All injury reports at USKRA, LLC sanctioned events are to be filed on the date of the mishap
with USKRA, LLC. Failure to report any injury may result in denial of claim by the appointed
Insurance Company. All injuries are subject to examination by a designated physician.
2.7 Firearms and weapons
A. Firearms and other weapons are not to be displayed at any USKRA, LLC sanctioned event, at
anytime. Person or persons disobeying this rule are subject to prosecution and/or being ejected
from premises. Constitutionally, we are guaranteed the right to keep and bear arms. If you are
licensed or otherwise permitted to have a firearm in your vehicle, you may do so, but if you
remove the aforementioned items from your vehicle, threaten others with any type of
dangerous weapon, or point any type of weapon at anyone from within the confines of your
vehicle, you may be prosecuted to the fullest extent of local, national, and/or federal laws.
2.8 Law Enforcement
A. Any legal authority hired by the track is given the right by USKRA, LLC and the host
track to enforce all county, state and federal laws.
2.9 Driver Age, Weight, and Skill
A. The class structures are based upon minimum weight and age requirements for all classes.
In order to participate in USKRA, LLC sanctioned race events and/or accrue USKRA,
LLC series points, drivers must meet the age and weight criteria.
B. It is the responsibility of all competitors to ensure their kart meets the minimum weight
required. Competitors are advised to check their combined kart + driver weight at each host
facility, and to scale the kart + driver with an empty fuel tank before competing.
C. To compete in any non-restricted class, a competitor must be above age 15 by January 1, of
the current race year to be eligible to compete in any adult class desired for any sanctioned
event. The exception to this rule is, drivers of age 12-15 may compete in the Junior Limited
Open class at a minimum weight of 280lbs.
D. Adults over the age of 15 may not compete in restricted classes.
E. “LO206 Kids Karts” is a class for children who begin the racing season on 01-01 of the
current year below the age of 8 only.
F. Classes are subject to change at the discretion of USKRA, LLC.
G. Events ran under USKRA, LLC rules are not automatically considered to be USKRA, LLC
sanctioned events. USKRA, LLC events are only those specifically denoted as such by
USKRA, LLC, Inc.
H. Minors are required to have a signed minor release form and certified copy of their Birth
Certificate registered on file with USKRA, LLC.
I. All drivers may be asked to demonstrate the minimum required skills to enter a class if
requested to by a USKRA, LLC official. If the skills of the driver are not deemed adequate
to meet or exceed the class standard of their fellow participants to race in a class, the driver
may be asked to gain more experience prior to entering into active competition, for their
own safety and that of their fellow competitors.
2.10
Competitor and Crew Conduct
A. Karting is a family-oriented sport. All USKRA, LLC members are to conduct themselves
in an orderly, professional manner. Please respect each other. Verbal abuse or physical
violence against any individual, official, participant, spectators, or other persons(s) at a
USKRA, LLC sanctioned event will subject the offender to immediate ejection from the
event site, possible suspension of racing privileges for a period of time to be determined by
USKRA, LLC, and when determined necessary, legal action will be taken. USKRA, LLC
events are not a place for persons with hot tempers and bad attitudes.
B. Disorderly Conduct shall be grounds for immediate ejection from any USKRA, LLC
sanctioned event. Disorderly Conduct includes abusive language, fighting, arguing with
race officials, disorderly or un-sportsman-like conduct, profanity, unusual behavior, and
intentional destruction of karts or equipment, and shall be grounds for ejection from the
premises for any length of time deemed necessary by any USKRA, LLC official or the host
track officials, and legal actions if deemed appropriate; this includes Drivers, Pit Crews
and Spectators. The owner of a racing team is responsible for the control and actions of
their pit crewmembers.
C. If a crewmember is asked to leave the facility for misconduct and refuses, the competitor
may also be disqualified and subjected to other penalties at the discretion of USKRA, LLC
and/or the promoting organization.
D. No physical contact, verbal abuse or violence of any kind will be tolerated. Anyone
causing bodily harm to any host track official or USKRA, LLC official will be prosecuted
to the fullest extent of the law and permanently suspended; this is a Zero Tolerance policy.
E. No one is permitted to harass participants, spectators or any other person. Violators of this
policy may be asked to leave the facility. Harassing USKRA, LLC and/or track officials
are grounds for automatic disqualification for the day. This includes drivers, pit crews,
family members and spectators of any competitor. Refusal to abide by these rules will
result in being escorted from the premises, or if necessary, violators of this rule will be
physically removed from the site by Law enforcement as needed. Should this occur,
charges will be filed if desired by USKRA, LLC and/or the host facility.
F. Unauthorized entry into a competitor’s pit area without their expressed permission is not
advised. For your safety and the safety of others, do not enter another person’s pit area. If
there is a problem, the unauthorized entrant will be assumed responsible and may face
disciplinary action including, but not limited to ejection and/or suspension.
2.11 Alcohol and illegal drugs
A. Zero Tolerance policy. Alcohol and illegal drugs are not permitted during any sanctioned
event.
B. Anyone found consuming alcohol, or determined to be under the influence of alcohol
during an event may be asked to leave the premises.
C. Anyone found using illegal drugs will be reported to the local authorities.
D. Any driver, owner, or pit crew violating this rule may result in disqualification of the kart
and loss of purse and points for the current year.
2.12 Waiver of Liability and Minor’s Releases
A. All persons desiring to enter the event property are required to read, understand and sign
the required document before entering. This is for your protection and the protection of the
promoting organization.
B. Failure to sign the required documents will be grounds to prohibit entrance to an USKRA,
LLC sanctioned event, and ejection from event premises.
C. For insurance purposes and for the safety of any person entering competition or a restricted
area, the signing of a Minor Release is required for any person under 18 years old entering
the premises. The Minor Release requires a signature of the legal guardian of any minor.
You are encouraged to review and fully understand the Waiver before signing. Members
under age 18 must have a notarized minor release form and other prescribed insurance
documentation registered with USKRA LLC prior to competing in any event. Any driver
believed to be below the age of 18 may be required to show proof of age.
2.13 Pit Area
A. Reserved pit spots may be available at the host facility’s discretion and as allocated by the
track owner at any fees prescribed by said party(s), and is not part of USKRA responsibilities.
B. No vehicles other than karts, track preparation equipment, or emergency vehicles are allowed
to drive on the racing surface unless expressed permission is given by the track owner.
C. Absolutely no driving of karts is permitted while under power is allowed in the pit area; this is
a safety issue. Failure to abide by this rule may subject the offender to a mandatory loss of 100
points, disqualification, and/or suspension. The kart engine is to be shut down immediately
after exiting the kart scales area.
2.14 Waste Disposal
A. Absolutely no oil or chemicals are to be dumped on the ground. All used oil must be disposed
of in designated barrels provided by the sanctioning raceway.
B. Disposal of tires is the responsibility of the kart owner.
2.15
Fees and Charges
A. USKRA, LLC Membership is both VOLUNTARY and FREE. USKRA, LLC assumes no
risk for members.
B. USKRA, LLC and the Host Facility may post fee schedules prior to all events. “Host
Facility” is described as the track holding the event(s).
SECTION 3 - RACE PROCEDURES, GENERAL KART AND DRIVER SAFETY
3.1 Registration
A. All drivers must register prior to entering the race surface area.
B. If the driver is a minor, a Legal Guardian of the driver must accompany the driver to
registration, and the minor must be properly registered.
3.2 Pre-Race Technical Inspection- Personal Safety Equipment
A. All personal safety equipment is subject to, and shall be made available for pre-race tech
inspection.
B. All drivers are required to wear an abrasion-resistant, non-heat shrinking jacket and long,
abrasion-resistant pants or a racing suit, neck brace, gloves, and a helmet as specified.
C. Helmet must be in good overall condition and is subject to pre-tech inspection.
The helmet must include eye protection. Both are to be worn at all times while under power
on the track.
D. Neck Brace- Collar type, unaltered neck braces designed for motor sports use are
mandatory in all classes.
E. Driver Apparel (Jackets, Pants, Suits)-Drivers are required to wear long-sleeved jackets of
leather, or an abrasive resistant material such as denim; no short-sleeved shirts. Materials
that will shrink or catch fire easily are not permitted. Full-length jeans or protective race
pants are required; no shorts or cut-offs.
F. Racing Gloves are mandatory. Fingerless gloves are not legal.
G. Hair Restraints are mandatory if a participant’s hair extends appreciably from beneath
helmet level. In such an event, it is mandatory that the participant wear a “balaclava” or
head-sock to retain hair in a safe manner away from any rotating, reciprocating, or moving
equipment on the kart.
H. “Loose” apparel items such as scarves, bandannas, hoodies, loose belts, etc. are not
permitted to be worn by competitors..
I. Arm Restraints are mandatory in Champ karts and must be attached via a welded
connection to the kart frame.
J. The use of Body Armor (rib and/or chest protection devices) is highly recommended in all
classes, and is mandatory for drivers ages 12 and under.
K. The safe use of hearing protection devices is recommended but not mandatory.
L. Open-toe shoes such as flip-flops and sandals are not permitted.
3.3 General Safety Equipment
A. It is the responsibility of the driver or Legal Guardian to provide quality safety items for
use by the driver. USKRA, LLC assumes no legal responsibilities for anyone injured due to
inadequate safety gear.
B. Competitors are requested to have all safety gear before attending a race. USKRA, LLC
cannot guarantee these or any other items to be available for purchase from trackside
vendors.
C. Each kart team is strongly encouraged to have a working fire extinguisher. Please keep
extinguishers visible and easily accessible not only for yourself, but for others in your pit
area.
D. Kart teams are responsible for keeping their pit area free of litter and dangerous obstacles.
E. Oil and other liquids are to be disposed of properly, and not dumped on the ground.
Anyone caught dumping fuel, oil, prep, or tires will be subject to suspension and fines as
applicable.
F. It is requested that all Flammable liquids be stored in an approved container for that liquid
and marked “Flammable”.
3.4 Pre-Race Kart Safety Inspection:
A. All karts are subject to pre-race inspection. A safety sticker will be placed on the nose of
the kart to signify that it has been through safety tech.
B. All steering and brake components must be doubled-nutted, cotter keyed, and/or safety
wired.
C. Front Wheel Hubs must be cotter keyed.
D. Axles must have retaining clips, and are recommended to be safety wired.
E. All drivers must weigh in after any Heat, and the Feature.
F. A minimum of three karts, or any number as directed by the Race Director will determine
how many karts are subject to be impounded for technical inspection after each main event.
G. The Technical Director will oversee tech for each class. Full tech or partial tech may be
performed. Technical inspection may be waived at the Tech Directors discretion if the top
three racers unanimously consent.
H. The Technical Director under direction of the Race Director has the final decision on all
kart tech items, and any item deemed unsafe must be resolved before entering the track
race area.
I. All driver personal safety equipment and race equipment is subject to a pre-tech inspection.
There will be a safety inspection required for all karts before being allowed to enter the
racing area of the track. Any kart not passing safety tech will not be allowed on the track.
J. Declining engine tech inspection when requested by a USKRA, LLC appointed official
shall be considered as an intentional and flagrant violation and will result in the loss of all
points for that day. Engine teardown is to be done by the appointed tech official(s) only,
with no one else allowed in the tech room. Anyone else entering the tech room is subject to
disqualification of their entry, points, and/or suspension at the track owner/promoters
discretion.
K. The first, second, and third place finishers from each feature will proceed to the impound
area immediately after leaving the scales, unless otherwise directed by the Technical
Director; failure to comply will result in disqualification. Karts and/or drivers competing in
successive classes must obtain permission from the appointed tech officials prior to leaving
the impound area, and are advised to obtain permission prior to racing their first class event
to avoid confusion.
L. The Technical Director at any USKRA, LLC sanctioned event is appointed by the Race
Director of USKRA, LLC
M. The Technical Director’s decision may be reviewed by the USKRA, LLC Race Director.
N. USKRA, LLC reserves the right to perform pre-race and/or post-race tech, fuel checks
and/or engine techs at their discretion, at any time during an event.
O. Any kart is subject to full inspection by a USKRA, LLC official at any time. Failure to
comply will result in immediate disqualification. Karts must have an inspection sticker
affixed securely on the kart or it may be refused entrance to the track.
P. Any item not covered in these rules will be acted upon by the track officials as situations
arise and will be added as an addendum to the rules if deemed necessary.
3.5 Tires, Tire Prep, and Tire Warmers
A. During the 2014 season, tire compounds and manufacture are open. You may use any
manufactured brand and any compound of kart tire, maximum 37” Diameter.
B. The use of tire prep is legal in 2014, however all competitors and/or their legal guardian are
responsible for its safe use, and assume all responsibility for its use. USKRA, LLC
assumes no liability for the use of any tire prepping or cleaning materials.
C. The use of tire warmers is permitted, and the competitor or their legal guardian takes full
responsibility for the use of these items, and these items must remain in the competitors pit
area only; do not bring these items to the grid. Any pit using a tire-warming device of any
kind must also have a charged fire extinguisher in good working condition, available for
inspection if requested by any USKRA, LLC official.
D. Any open flame used to heat tires is not allowed.
E. Use caution around all flammables.
3.6 Driver’s Meeting
A. All drivers must attend the mandatory daily pre-race driver’s meeting. The race director
may elect to relegate any driver who misses the drivers meeting to the rear of all events that
race day. It is requested and recommended that the Legal Guardian accompany racing
minors to the drivers meeting.
B. On-track procedures, starting procedures, flag procedures, re-entering the racetrack,
lapped traffic instructions, events scheduled, race time limits, and safety issues may be
discussed at the driver’s meeting.
3.7 USKRA, LLC Official Racing Format
A. Our racing format is based upon the belief that having to actually race your way into the
feature is the best way to go, and reduces the effects of “qualifying tires” and “qualifying
engines”. At the end of the day, win or lose, at least a competitor has had the opportunity to
race in at least one event instead of driving numerous miles to a track, running a few
qualifying laps, not making the field, and never getting to race.
B. The race format may be altered, dependent upon safety considerations, and time allotted if
local curfews require the races to start or end at a certain time, as well as the availability of
equipment, scoring and officiating resources, and other local factors including weather.
C. All races, including but not limited to Heats, Features, and Money Races are subject to a 15
minute time limit as determined by the Race Director.
D. All races, including Heats, Features, and Money Races may be subject to time constraints.
Races will be limited to the number of laps given at the event, based upon the number of
competitors, as announced by the Race Director, or the “15 minute rule”. See Section 3.9
“Racing Flags” for a full explanation of the “15 Minute Rule”.
E. Electronic scoring will be used in the racing format whenever possible. When transponders
are used, it will be done to determine the racer’s position on the track for scoring and
alignment purposes.
F. At USKRA, LLC events, we do not qualify with transponders, we qualify by racing.
Competitors will race a minimum of one Heat, or a maximum of two Heats, depending on
the number of karts entered in each class.
G. Before racing in any USKRA, LLC sanctioned event scored by transponders, you will be
required to secure rental of a transponder compatible with the scoring system. It is the
competitor’s responsibility to make sure in advance that the proper transponder holder is
installed on their kart, and that it is attached securely to the kart at the area located at the
front of the right side nerf bar.
H. All classes will run heats divided into groups of karts as based upon the number of entries
in that class.
I. The initial lineup for all Heat races is performed by random selection electronically by the
use of a Random Number Generator; this is referred to as your “luck of the draw” number.
Automating this process saves time in creating the initial Heat lineups.
J. Competitors who are scheduled to race in a certain event are considered as “racers” in that
event. Any racer who cannot, or does not start by taking the green flag which signifies the
start of the race, will be allotted DNS points for that event, and may not be rescheduled for
another race unless the number of competitors in the class are equal to, or less than the
minimum number of karts to make a full field at that track, for that class Feature, or at the
Race Director’s discretion.
K. If any race cannot be started double-file in a timely fashion, the race will be started
single-file.
L. A “field” is described as, “the number of competitors appointed for competition”. In the
event classes are combined into a single Heat race to make a field, each class shall be
inverted separately for the second Heat, but the Primary class will always start up front for
safety.
M. In the event of having a Restricted Class without enough participants, the kart group with
the larger plate size will be the Primary class and will start in front of the next lower plate
size class, and the classes will be scored separately.
N. In the event of having an Adult Class without enough participants, the kart group with the
lighter weight will be the Primary class and will start in front of the next heavier class, and
the classes will be scored separately.
O. The maximum number of karts allowed to compete in any race is determined by the track
size, or as specified by the Race Director. For examples, a 1/4 mile track will race
approximately 30 competitors; a 1/5 mile track will race approximately 24 competitors.
EXAMPLE, Track size: 1/4 mile
Kart Count and Transfers from each Heat:
 30 karts or less, all transfer to Feature
 31-60 karts, Top 15 transfer from each Heat (2 Heats)
 61-90 karts, Top 10 transfer from each Heat (3 Heats)
EXAMPLE, Track size: 1/5 mile
Kart Count and Transfers from each Heat:
 24 karts or less, all transfer to Feature
 25-48 karts, Top 12 transfer from each Heat (2 Heats)
 49-72 karts, Top 8 transfer from each Heat (3 Heats)
 73-96 karts, Top 6 transfer from each Heat (4 Heats)
P. Heat Race Lengths for equal to, or less than the maximum number of competitors to
make a complete field of karts are as follows:
 1-5 competitors = 4 laps
 6-10 competitors = 6 laps
 11-16 competitors = 8 laps
 17 -23 competitors = 10 laps
 24+ competitors = 12 laps
Q. The USKRA, LLC method of determining kart starting and transfer positions:
For classes with equal to, or less than the maximum number of racers to fill a Feature
race (24 or less on a 1/5 mile or 30 or less on a 1/4 mile): When there are less than the
maximum number of karts to fill a class, all competitors automatically transfer to the
Feature. In this scenario each racer will have two Heat separate races to compete in.
Starting positions for the First race will be in order as chosen by random selection, via the
Random Number Generator, and the second race will be started with the lineup inverted
from the first Heat race starting positions. In this scenario, Starting position for the Feature
shall be based upon the highest scored value of combined Heats 1 and 2. In the event of a
tie in points for any position, position goes to the highest scoring driver in the first Heat
(i.e. If Kart number 12 from the first Heat wins and finishes second in the second Heat, and
Kart number 33 finished second in the first Heat and won the Second Heat, they are tied in
points after both Heats. In the Feature lineup Kart 12 will get the pole position and Kart 33
will start on outside pole); the same goes for any additional Heat points totals in which
there is a tie in points. In other words, it is from the “luck of the draw” number obtained for
the initial Heat number random draws that breaks a tie.
R. For classes with greater than the maximum number of racers entered in a class:
(>24 on a 1/5 mile or >30 on a 1/4 mile): The number of karts registered to race in any class
will determine the number of heats required for each class. If the kart count signed up for
any class exceeds the maximum amount allowed on track, the class will be split equally as
possible, as many times as necessary, to obtain a starting field equal to or below the
maximum number of competitors allowed to start the race. Competitors will start their
Heat in the starting position assigned by random number selection for that class. Racers in
this scenario will compete in One Heat in an effort to transfer to the Feature. In this
scenario, an appropriate amount of racers will transfer from each Heat to the Feature event,
as based upon their finishing position, number of karts transferred per Heat, track size, and
maximum number of competitors allowed to compete in the Feature event for that class.
S. Each class will have one Feature race for competitors who have successfully qualified to be
transferred through the Heat(s).
T. Feature Race Length for all classes is 20 laps.
U. The finishing order in the Feature race and the results of post-race technical inspections
will determine the final race results and points awarded.
3.8 Track Officials and Race Procedures
A. Track Officials include, but are not limited to: Race Director, Course Flagman, Track
Steward, Corner Flagmen, Scoring Person(s), Grid Steward, Scales Person, Tech
Official(s), and members(s) of the Transponder Team.
B. The use of the term,“man/men”, as used in job descriptions is a generic title that applies to
a worker (such as “Flagman”), and may be held by either a male or female.
C. The Course Flagman is in charge of controlling all on-track events.
D. Corner Flagmen use a yellow flag to notify drivers of unsafe conditions in specific
corners, however the display of a Yellow Flag by a Corner Flagman does not always
signify a full-course caution.
E. During any event, it is the driver’s sole responsibility to pay attention to and obey the
instructions of the Course Flagman, Corner Flagmen, and Track Steward.
F. The Track Steward, assisted by the Course Flagman and Corner Flagmen will instruct
competitors to align as ordered. Failure to comply is grounds for ejection from the race and
loss of points for the event.
G. The Course Flagman uses flags and available race track lights to control the races (green,
yellow, red, white, blue & yellow, checkered, and black).
H. The Course Flagman communicates with the Grid Steward to determine when it is safe for
the next group of karts to enter the track.
I. The Grid Steward will give the command to “Start your engines”, either verbally or
through the use of hand signals.
J. Competitors will have approximately 90 seconds to be on the track, from the time the Grid
Steward gives the command.
K. It is the Course Flagman’s job to relay information regarding the status of the race to the
competitors by waving the various flags, and the use of track lights.
L. It is the responsibility of the drivers to observe the Course Flagman’s commands during the
race, and to obey the flagman’s commands.
M. It is the driver/Legal Guardian’s responsibility to ensure that their kart has a
transponder/holder securely attached to their kart when an electronic scoring system is
used. If a kart does not finish a race with the transponder onboard the kart, they will not be
scored. If a transponder is damaged during a race, but the kart and driver are allowed to
continue racing, the host facility shall be responsible to determine the finishing position of
said racer. If a transponder is damaged due to improper installation, the competitor and/or
their legal guardian shall be held liable for replacement of the unit.
N. Notice to all persons: Do not attempt to harass the Course Flagman about events that occur
on the track, either verbally or through the use of body gestures; doing so may result in
your immediate ejection and/or suspension. Bring any pertinent questions or complaints to
the Race Director a calm, reasonable manner.
3.9 Racing Flags
3.9.1 Green Flag
A. An unfurled, waved green flag signifies the start/restart of a race.
B. When entering the track for a race, line up immediately and prepare to take the green on the
1st lap.
C. The Green flag may or may not be given on the first lap.
D. Pole position will set the pace as directed by the Course Flagman and Corner Flagmen for
start/restart.
E. Prior to the commencement of a race, all karts are to remain in their proper starting position
or the race may not be started; or a green flag may be displayed for safety, followed by a
yellow flag signifying a complete re-start at the Course Flagman’s discretion.
F. When the Course Flagman displays a rolled up green flag to the drivers, it signifies that the
race start/restart is imminent.
G. When the track course lights are not lighted, all racers should be prepared to start.
H. When it has been determined that all Karts are lined up in the proper position and the track
is clear, the Course Flagman will display the unfurled green flag to signify the start/restart
the race at his\her discretion.
I. All re-starts are under the control of the Course Flagman. Passing is not allowed until the
green flag is waved, no matter where you are in the field. Failure to stay in line until the
Green Flag has been displayed may result in your kart being relegated to the end of the
field, or in extreme cases, black flagged.
J. When the Green flag is displayed unfurled, the race is officially underway. The Green light
will also be on.
K. Prior to the start or re-start of a race, if a driver drops out of the pack due to a terminal
mechanical difficulty, the balance of the field will move straight ahead to fill the position,
whether double file or single file.
L. On re-starts after a caution, the race will resume immediately when the green flag is waved.
M. Once the green flag is initially displayed for the start of the race, no one else will be
allowed to enter the track for that event; no exceptions.
3.9.2 Yellow Flag (Full Course Caution)
A. A Yellow (Caution) Flag is displayed to indicate to racers the presence of a dangerous
condition on the track.
B. A “Full Course” Yellow flag may not be thrown by the Course Flagman unless it is
determined that a dangerous situation exists on the track.
C. If minor altercations or single kart accidents occur, or if an accident occurs that does not
constitute an immediate hazard for other racers, or involve known, visible injuries to any
driver, and is outside of the racing groove and the Course Flagman determines that there is
no need to halt race progress, no Full Course Yellow flag will be displayed.
D. When a Yellow flag is displayed by the Course Flagman, it signifies a full course caution;
the Green light will be extinguished and the Yellow Caution light will be displayed.
E. DO NOT race back to the line when a full-course yellow flag is given. Racing positions
will be determined by the last full lap completed by the race leader, and karts will be lined
up accordingly.
F. Laps will not be counted while under a Yellow Flag condition.
G. In the event a Full-Course Yellow or Red flag condition occurs during the last lap of the
race, the race will be re-started with both the Green and White flags displayed, signifying
the start of a “one-lap trophy dash”.
H. All races will end under Green racing conditions.
I. When the track is under a Full Course Yellow flag, slow down, but do not stop. Raise your
hand to indicate to the drivers behind you that you are slowing, and hold your position. Do
not pass any karts while slowing unless you would create a dangerous situation by not
doing so.
J. Re-starts will always be single file after the first lap is completed.
K. The race leader is advised to raise their hand so that the field knows to reform in single file
for the restart.
L. All of the participants involved in any incident causing a Full-Course Yellow flag
condition will start at the back of the field on the restart. If you are involved in the incident
do not expect to “get your spot back”. Note that this rule doesn’t state “who caused the
yellow”, it’s says, “all karts involved” including karts that spun to avoid the incident before
the full course caution was displayed.
M. Yellow flag laps and pace laps are to be run at a slow, safe pace set by the race leader under
direction of the flagmen.
N. Competitors should always look out for safety personal on the track, and watch the officials
for signals.
O. Re-start positions will be based on the last competed and scored green flag lap. If you don’t
know where to re-start pull out of line near a corner flagman or the Track Steward and raise
your hand so the Official can position you in the correct spot.
P. No passing will be allowed when yellow flag is displayed. The yellow flag is used in an
attempt to protect everyone.
Q. In cases of accidents that result in the use of a yellow or red flag, racers involved in an
incident will be permitted, in a timely manner, to be re-aligned and re-start.
R. Engines can only be restarted after the race has begun only when the engine has shut off
due to an accident, or if for any reason the engine shuts off during the occurrence of a full
course yellow flag. Minor repairs (such as putting the chain back on) may be performed by
the driver or ONE crewmember, in a timely fashion, when the engine is shut off. Never
attempt to put a chain back on with the engine running!
S. One crewmember may be allowed to cross the track surface and enter the track infield only
after being granted permission by a Race Official, and are advised to cross the track with
extreme caution. Injuries to persons crossing the track are not the responsibility of the Host
Facility or USKRA, LLC.
T. There will be no prescribed waiting period for persons to effect lengthy repairs and the race
will be restarted in a timely fashion, at the flagman’s discretion.
U. If a kart is not ready to race after the field is reformed, the driver is to move their kart and
themselves to a safe location.
V. If you spin out or otherwise lose positions on the track and are still under power and
capable of continuing, the caution flag may not be thrown. You are expected to re-enter the
race if you choose, or move to a safe location.
W. The “Racing Groove” is defined as the inside line. If you are not up to speed for any reason,
please move to the outside (top) of the track surface, out of the way of your fellow
competitors.
X. Do not drive a kart that is not back up to speed into the racing groove if anyone is within a
questionable distance of your kart. Creating an unsafe condition for other racers may result
in your being black-flagged at the Course Flagman’s discretion.
Y. Any kart causing three yellow or two red flags may be Black Flagged (disqualified) from
that race, and if disqualified, must immediately leave the track surface.
Z. In the event of a full-course caution, racer positions revert back to the last completed lap.
Any driver who refuses to realign in the position they are instructed to, will be disqualified.
3.9.3 Yellow Flag (Corner Caution)
A. A Corner Yellow does not signify that a race has been interrupted; the race may, or may not
still be underway.
B. When displayed by a Corner Flagman, this flag indicates a potentially dangerous situation
has occurred in the immediate vicinity, and the driver is to proceed with caution, however
the driver is to heed the commands of the Course Flagman and the track lights to determine
if the race is still under green flag conditions.
C. A Corner Flagman will usually have only one flag at their disposal (A Yellow Flag), and
may be warning the drivers of a RED flag condition. It is the driver’s responsibility to heed
the direction of the Course Flagman’s flags and track lights. If the Course Flagman does
not display the Yellow Flag, the race will continue to progress as scheduled.
3.9.4 Red Flag
A. A Red flag signifies to all competitors to come to a complete stop in a safe and orderly
manner as quickly as possible, and to avoid potentially dangerous conditions on the track.
B. After slowing to a safe stop, drivers will await further instruction from Track Officials.
C. When directed, drivers shall proceed safely to their re-start position as directed by Track
Officials or the Course Flagman.
D. Shutting your engine off under a Red Flag condition is optional, however you must be on
the track ready for competition when the green flag is redisplayed, or you will be out of the
race.
E. Realignment of the field shall be done according to the last completed lap under green.
F. If the red flag occurs at or after the halfway point, and time or weather constraints require
the end of the race, the race will be scored as a completed race, race results will reflect
positions recorded during the last completed green flag lap, and karts involved in the
incident will all be given points based upon their positions from the last completed lap. The
officials will make every effort for the event to finish under a green flag, however time and
local conditions may require the race to be scored as complete. Red flagged races will be
declared official if the track officials decide the event cannot be completed.
G. If a kart involved in an accident is yours, it is the Driver/Legal Guardian’s responsibility to
decide if their kart can restart the event; additionally, if the Race Director determines that
any kart is unsafe to race, that kart will not be permitted to restart the event.
H. Any kart/driver that has flipped over during the race will only be allowed to restart the race
with the permission of the Track Officials and the Emergency Medical personnel’s
approval, and by doing so, the Driver/Legal Guardian willingly signifies that the driver is
in sufficient physical and mental condition to continue in competition, and that the kart is
believed to be in overall safe racing condition.
I. Any driver causing a red flag condition may be subject to not restarting, as determined by
the race director.
J. Any driver leaving the racetrack, due to an accident, by ambulance, will not be allowed to
restart in the race in which the accident occurred.
K. Any kart involved in an accident whose driver is transported to a health care facility is
subject to post-race tech inspection.
L. If any driver does not return from the health care facility prior to the end of post tech, scales
tech (weighing) will be waived, however if the accident occurred on the final lap of the
race, the engine is still subject to technical inspection.
M. All karts that are racing at the time of a red flag may have their engines restarted by one
member of their pit crew. Those karts involved in the accident that were determined to be
the reason for the red flag may have their engines restarted but must go to the rear of the
field in the position(s) directed by Track Officials.
N. In the event of a red flag condition due to an accident, the Grid Steward may allow the
Spouse, Parents, or Legal Guardians of an injured racer onto the track, but they must not in
any way interfere with the Track Officials, USKRA, LLC Officials, or Safety Personnel.
O. We realize that parents are concerned for their children. Our concern is also for the welfare
of the racer.
3.9.5 Blue Flag with Orange Stripe
A. This flag signifies that a kart is attempting to lap your kart, and is also known as the
“Move-Over” flag.
B. Pull to the outside of the track surface, but continue racing if desired. Anyone continuing to
block the progress of the faster karts without moving over may be black-flagged and
disqualified.
3.9.6 White Flag
A. Signifies that one lap remains in the race.
3.9.7 Checkered Flag
A. Signifies the completion of the race.
B. The checkered flag is waved when the person leading the race is about to cross the
start/finish line at the completion of the last lap.
C. The first person to complete the designated number of laps for the race and take the
checkered flag at the start/finish line is declared the winner.
D. All competitors are scored by the number of laps completed, and their final position
recorded after crossing the start/finish line in front of the Course Flagman’s area.
E. Once you have crossed the Start/Finish line, slow to a moderate pace and exit the track,
then proceed slowly to the scales to be weighed, and if required, immediately to the
post-race tech area. Any racer directed to the post-race tech area, which does not do so
immediately when directed, will receive DQ points.
F. The “15 minute rule” means that if the race is not finished within acceptable time
constraints (15 minutes), upon the next Yellow Flag, the race will go a
“Green-White-Checkered” scenario. The flagman will give the signal by displaying a
rolled green flag, and a rolled white flag simultaneously, in the same manner displayed
when there are two laps remaining in the race, while under yellow The green will re-start
the race, the white will be displayed the next lap, and then the checkered on the following
lap. In such an event the race will be considered final, and all competitors will exit the
track.
3.9.8 Black Flag
A. A rolled Black Flag pointed at a driver is a warning to the driver that they are in danger of
being disqualified for a driving infraction. You will be warned only once with a rolled
black flag, second warnings will result in a waved black flag and disqualification.
B. If the Black Flag is waved at your kart, you must exit the track in a safe and cautious
manner within two (2) laps because you have been disqualified for a driving infraction or
unsportsmanlike conduct, unsafe equipment, or loss of safety apparel.
C. If any participant blatantly ignores a waved black flag, that person may be disqualified for
that race day in all classes.
D. If the flagman waves the black flag and points to you while you are racing, you must slow
down and pull to the outside of the track surface, outside the racing groove whenever
possible, using caution so as not to interfere with the other racers, and then exit the track in
a safe and cautious manner.
E. If you are black-flagged for any reason you must leave the racing surface. Do not disregard
or disobey the flagger’s command. By complying you may be scored based upon the
position you exit the track, the finishing position of all karts at the end of the race, and the
number of laps completed by each competitor in that race after all karts have crossed the
start/finish line immediately after the race winner takes the checkered flag. Refusal to exit
the track when ordered to do so shall result in a loss of all points for that race day- no
exceptions.
F. Reasons to be black-flagged may include:
 Failure to obey the Move-Over flag, or obey any of the Flagman’s commands.
 An unsafe situation has developed with your kart while racing.
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Your kart is off speed to the point where it is a danger to other drivers.
Reckless driving, unsafe, or unsportsmanlike conduct.
G. “Unsportsmanlike Conduct” includes, but is not limited to: Flipping off any USKRA, LLC
Official (giving them the bird), slapping at a competitor while on the track, trying to pull
the spark plug wire off, or otherwise disable a competitor’s kart while on the track.
H. Any unsportsmanlike actions whether on or off-track resulting from a black flag situation
may also result in suspension from any USKRA, LLC sanctioned event for any unspecified
number of events.
3.10 Practice and Events- Procedures
3.10.1 Practice Schedule
A. You may not enter the track race surface without first acquiring a safety inspection sticker.
Whenever possible, practice sessions, both “open”, and “by class” will be held prior to the
first scheduled race.
B. Heat Races will begin following the Driver’s meeting.
C. No practice without the Course Flagman is permitted.
D. The length of practice allowed is determined by the Course Flagman, usually as defined by
time constraints and not necessarily by a specific number of laps per class.
E. If it is determined that foul weather may be a time-limiting factor, some or all Race day
practice sessions may be scratched altogether.
3.10.2 Hot Grid and Pre-Grid Rules
F. The “Grid Area” is comprised of the “Pre-Grid” and the “”Hot Grid”.
G. The “Hot Grid” is the area for karts that are going onto the track.
H. The “Pre-Grid” is the secondary lineup area for the class following the “Hot Grid” karts.
When called to the Grid Area, bring your kart, and be ready, prompt, and courteous.
I. The use of a “Pump-Around” is not required. Bring your kart to the grid race-ready.
J. Fuel Tech can be performed at any time at the Race Director’s discretion. A fuel sample
may be taken from either the tank or the fuel line.
K. The driver, kart and one (1) person to start the kart are the only persons that are allowed in
the Hot Grid Area. Any unauthorized persons found in this area may be instructed to leave
the Hot Grid area.
L. All competitors are responsible for knowing when their class is to run or practice, and to be
on the grid in a timely fashion.
M. Lineup is based upon the starting position posted for your kart, for that event. Be on the
grid, know your lineup, and be in position before entering onto the track surface. Getting in
line properly on the grid makes lineup on the track easier and quicker.
N. The races will run as scheduled. If you do not get your kart on the track before the first
green flag starts the race, you will not race in that event, and will receive DNS points.
O. If the pole sitter does not obey the Course Flagman, that driver may be swapped with the
racer directly behind (relegated to the 2nd row inside starting position).
P. The Course Flagman will control the start of the race from the start/finish line.
Q. The Grid Steward will give the command to start engines approximately 90 seconds before
karts are allowed on the track.
R. All karts will have approximately 90 seconds to leave the Hot Grid and enter the track
racing area. This gives competitors approximately 3 minutes from the time they are given
the command to start their engine, and be on the track.
S. When the karts enter the racetrack, the driver in the pole position will raise his/her hand and
all of the racers are to locate their karts in their correct starting position. Failure to comply
by any competitor may result in being relegated to the rear of the field.
T. Any driver passing the pole sitter after his/her hand is raised, before the race is started, may
be sent to the end of the field.
U. The driver in the pole position will set the pace for the start of the race under the direction
of the Course Flagman.
V. All activity on the track and in the pits is subject to the immediate control of the Race
Director, Grid Steward(s), Track Steward, and Course Flagman. All competitors shall
adhere to their directions.
W. It is the responsibility of all competitors, including the pole sitter, to obey the Course
Flagman’s commands. The Course Flagman starts the race. The Pole Sitter does not start
the race, but does set the pace under the Course Flagman, Track Steward, and Corner
Flagman’s supervision.
X. All karts must stay in line and maintain pace.
Y. If an accident requiring the Yellow or Red flag occurs prior to the completion of one lap, all
drivers are to realign in their original starting position.
Z. A single file restart may be signaled at the Flagman’s discretion, even before the first lap is
completed if the racers do not realign in a prompt manner or otherwise are experiencing
difficulty getting the first lap completed while starting two wide.
AA.
A “Tomahawk chop” single hand signal displayed by the Course Flagman indicates
a single file start/restart.
3.11 Restarts after One Lap is completed
A. Drivers are to realign in the order in which their kart was scored on the last completed
green flag lap.
B. After one lap is completed, all karts will always restart single file.
C. If competitors do not realign in a timely fashion, all karts will be stopped and placed
into their proper restarting position.
D. Failure to remain in your designated restart position as ordered by any track official
may result in being sent to the rear of the field, or disqualification.
E. When all karts are in the correct single file order, the Course Flagman will hold a rolled
up green flag to signify the imminent restart of the race at his discretion.
F. The flagman may restart the race at any point on an oval track from the backstretch to
the start-finish line, at the flagman’s determination of when the field is properly
aligned.
3.12 Time and Weather Constraints
A. If time or weather requires, the race(s) may be ended early, with points determined
according to the position last recorded.
3.13 Repairs
A. No kart may be repaired while on the track surface. Only the driver and one crewmember
may attend to his/her kart in the infield.
B. All entries involved in an accident shall start in the position assigned to them by the Race
Steward or Flagger.
C. Only Authorized personnel shall be in the infield or on the track at any time during the race
program.
3.14 Exiting the track
A. Whenever a kart slows from racing on the track, the driver must signal by raising their
hand high enough to be clearly visible from behind. This includes at the termination of
the race, prior to leaving the track surface.
B. The driver is not allowed to have contact with anyone until they have weighed-in after
any race.
C. Persons giving additional weights to a driver following any race so that the driver can
make class weight is strictly forbidden, considered to be intentional cheating, and will
result in a loss of all points for the season, up to and including the current date. No one
except the driver is allowed near the kart until after weigh-in is completed.
D. All karts that start a race must weigh-in; Heats, Features, and Money Races.
E. In the event of an equipment malfunction or driver injury that forces the driver to retire
from the race, points will be rewarded according to the position the kart is in when it
leaves the race.
F. All karts/drivers that finish each race are to weigh in immediately upon exiting the
track. Failure to comply will result in a loss of finishing position, and receive DQ
points, no questions asked.
G. The top 3 finishers must immediately impound their karts after Feature weigh-in, until
the engine is removed.
H. Two persons maximum allowed in the impound area per kart; the driver and a second
party.
I. The engine must be removed from the kart by the owner, and turned in to the engine
impound/tech area. Once this is done, the kart may be taken from the impound area
after permission is granted by the Tech Official.
J. If your kart is disabled and you are unable to exit the track while under power, or by
coasting, pull your kart to the infield and do not cross the track until the race is over and
all competitors have exited the track. Do not forget, you must still weigh-in to get DNF
points.
3.15 Competitor Actions
A. Repeated rough driving or poor sportsmanship will result in disqualification (See “Black
Flag” rules).
B. Any kart that leaves the racecourse may return, but only in a safe manner.
C. In all circumstances, if any competitor is not fully under control of their kart, or their own
facilities after re-entering the race surface, they will be black-flagged.
D. A kart may be considered as a weapon when under power and intentionally used to hit
another competitor. Please consider your actions and the consequences carefully.
3.16 Rainouts
A. An USKRA, LLC Sanctioned Event will be considered complete if all Heats have been
raced, however, a realistic attempt will be made to race all events, time permitting.
B. Some or all races may be rescheduled due to inclement weather. Rain checks or refunds
may be given at the Race Director and track owner/promoter’s discretion.
C. In the event of a partial rainout, points are awarded to racers in completed events for the
day.
D. First day rained-out races will start the second day events if/when the track is determined to
be in good enough condition to race.
E. If it is determined that First day Feature races are going to extend past a curfew, First day
race points may be awarded according to the Feature lineup positions.
F. USKRA LLC and the Host Facility will attempt to reschedule rained-out Second day
classes at a later date.
G. In the event any race(s) cannot be rescheduled, and Heat races have been completed,
Features points will be allocated based on the calculated feature lineup when Heats have
been completed.
H. If an entire event is rained out, USKRA LLC and the Host Facility will attempt to
reschedule another race dat.
I. In the event a rescheduled race is again rained out, zero (0) points will be awarded to all
competitors.
3.17Driver Safety
A. Any driver involved in an incident that disables their kart and places the driver in harm’s
way, is to immediately seek a position of safety, even if it requires abandoning the kart.
Karts can be replaced, people can’t.
B. Bump drafting is allowed, however if the end result of a secondary kart bumper-drafting
the first kart results in the first kart being spun out, whether while on the straight or during
traversing the corners, the driver of the secondary kart may be disqualified or sent to the
rear at the Corse Flagman’s discretion, while the rest of the field will be realigned to their
previous lap positions. If a driver feels that they are being rough-driven, he/she should
immediately raise their hand and wave off the offending driver. In such case, the Course
Flagman should warn the secondary driver with a rolled black flag only once. If the
secondary driver persists to be overly aggressive, they are subject to penalties including
being black-flagged. Safe driving practices are expected of all competitors without
endangering any of your fellow competitors.
C. Although it is understood some incidental contact will occur, intentional rough contact is
grounds for disqualification. If, in the judgment of the race official, a driver is intentionally
rough-driving another driver, the offending driver may be disqualified or sent to the rear of
the field on the current lap.
SECTION 4 - GENERAL ENGINE RULES AND TECHNICAL PROCEDURES
USKRA, LLC rules set forth are designed to be a guide for technical inspectors to ensure fair
competition within the USKRA, LLC, Inc. While USKRA, LLC encourages innovation and
engineering within its technical guidelines, certain modifications deemed to be against the spirit
and intent of rules set forth shall be declared illegal. It is the sole discretion of the Technical
Inspector to decide if any modification outside of the rules laid down here will be deemed illegal
for competition. If a modification is determined to be “undetermined”, the competitor shall pass
inspection for the immediate race day, and the modification in question will be brought before the
USKRA, LLC Tech Committee for review and advisement.
4.1 Fuel
A. Fuel is as denoted per class. Top End lube is permitted, however the end product must be
able to pass the appropriate tests.
B. The addition of oxygenating substances to the fuel or oil is illegal.
4.2 Fuel and Oil Samples
A. A sample of any/all competitors Oil and Fuel may be required for tech at any time during
race day. If a sample is requested by a USKRA, LLC Official, the requested sample must
be taken by the kart owner/representative, sealed and initialed by the kart
owner/representative in the presence of a Tech Official.
B. It is the responsibility of the kart owner to ensure that their fuel and oil is legal.
C. If requested, the driver or kart owner must immediately surrender a sample of fuel and/or
crankcase lubrication from the engine.
D. No oxygenating additives of any kind are allowed in the crankcase.
E. Anyone found guilty of oil or fuel infractions, whether intentional or unintentional, may be
subject to a forfeiture all seasonal points up to and including the current date.
SECTION 5 – REGISTRATION, POINTS, PENALTIES, AND AWARDS
5.1 Official Registration
A. Classes may be registered for in advance online, by filling out and e-mailing in Sanctioned
Event pre-registration entry blanks as made available when provided online at our website.
B. Any driver not registered by the Official Registration completion time may be required to
start scratch in any and all qualifying events, if they are permitted to enter by the Race
Director.
C. Racing Season- The “racing season” ends on the last day of the Grand Nationals, and the
new “racing season” begins the day following the end of the Grand Nationals.
D. In the first full year that a youth racer is over age 16, they must move to an adult class.
E. Youth racers may not move up to the adult classes until they are age 16 on January 1st of
the current racing season.
5.2 Feature Scoring Method
A. The driver who is registered for competition is the official entry into the event, and the
recipient of any points awarded. Relief drivers are not allowed. The driver who races is the
driver who gets the points.
B. Points are awarded for feature races based upon the USKRA, LLC prime points system.
C. In the event of a total rainout all entrants will receive 0 points until, or unless, the event is
rescheduled.
D. In the occurrence of season ending ties, ties will be broken by using the greatest number of
1st place finishes in events counting toward that position. If a tie still exists, the 2nd, 3rd,
etc. finishing positions will be considered until the tie is broken. During the season, ties
will be broken with the position awarded to the driver that first obtained the position.
E. Electronic Scoring Devices may be utilized.
F. Races 1, 2, and 3 are Single Points Events.
G. Race #4 is the Season Finale Grand Nationals Event, and is a Double Points Event.
5.3 Points Scoring System
(Finishing Position = Points Awarded)
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1st = 149
2nd = 139
3rd = 137
4th = 131
5th = 127
6th = 113
7th = 109
8th = 107
9th = 103
10th = 101
11th = 97
12th = 89
13th = 83
14th = 79
15th = 73
16th = 71
17th = 67
18th = 61
19th = 59
20th = 53
21st = 47
22nd = 43
23rd = 41
24th = 37
25th = 31
26th = 29
27th = 23
28th = 19
29th = 17
30th = 13
31st = 11
32nd = 7
DNF (Qualified, Started Feature, Did Not Finish) = points awarded according to “drop out”
position as tallied at the end of the race.
DNS (Qualified for Feature, Did Not Start) = 3
DNQ(Raced Heat(s) but Did Not Qualify) = 2
DQ = 0
5.4 Disqualifications and Penalties
A. When any competitor is disqualified, whether on the track, at the scales, in engine tech, or
at any other area on the host facility grounds, the officiating party is to contact the Race
Director immediately. Competitors may only remove an engine, part, or kart when directed
to do so by a member of the USKRA officiating staff. Removal of any item from engine
tech, scales area, or any area appointed by the officiating party, indicates that the owner
agrees to the disqualification. Once the kart or engine has been removed from the
appointed area, all rulings are final.
B. All parts must pass technical inspection. Broken or damaged engine or kart parts found in
post-race tech are not necessarily considered grounds for disqualification, but all tech parts
must be on the engine when teched, including the muffler, unless it is a “no-muffler” event.
C. Certain bolts on an engine may be sealed or painted at any point in the race day. If paint or
seals are tampered with, (For example, switching carburetors after a Heat) the engine
should be brought to the Head Tech Official to be re-painted or re-sealed, or the part will be
disqualified.
D. Any complete engine change after Heats must start in rear and must be re-submitted to tech
prior to racing that engine.
E. When an engine is determined illegal in tech, the driver will be subject to disqualification
and penalties. It is the responsibility of the racer to purchase a legal engine. Although
buying an unknowingly illegal engine is not always the racer's fault, it is still illegal and
unfair to be raced against other competitors with legal engines. The responsibility to build
and sell a legal engine is on the builder, and it is between the buyer and seller of the engine,
not USKRA, LLC.
F. If for any reason a competitor feels that they have been wrongly disqualified, or feels that
they have been scored improperly, they may submit a protest in writing by the driver, or
their Legal Guardian to the Race Director.
G. Protests should be submitted via a “Receipt Signature Required” mail or parcel service to
ensure delivery to the Race Director within 14 days of completion of the race that is being
protested.
H. Points for classes are not official until all protests have been reviewed and finalized by the
Race Director.
I. After 14 days, all finishing positions not under protest are declared official by the Race
Director.
J. In all cases, the Race Director’s decision shall be final and cannot be protested or reversed.
5.5 Types of Disqualifications
.
A. Unintentional (Part within .005" out of specifications). First Offense Penalty:
Disqualification and loss of points for the day in the class the engine was teched illegal in.
Restrictor plates will be teched when removed, and must pass tech regardless of the
temperature of the plate. A Restrictor plate is to be removed by the owner. It is the owner's
responsibility not to bend or scar the plate.
Second Offense Penalty for an Unintentional Disqualification in same season will result in
the same penalty plus a one race suspension
B. Intentional (Parts)- Part is blatantly illegal; person has made an intentional attempt to
enhance performance. For example, a +.100” stroker crankshaft in a Modified Stock
engine. Penalty: Disqualification and loss of Seasonal Points to date, including current
race.
C. Intentional (Fuel)- The use of “Hot” fuel or oil (utilizing illegal additives) is considered
blatantly illegal. Penalty: Any person(s) found guilty of fuel and/or oil tampering may be
suspended indefinitely, in addition to a loss of all events points for that day.
D. Fines- Tracks may choose to use USKRA, LLC rules, and financial penalties may be
enforced by that track as their rules state, but USKRA, LLC does not assess financial
penalties.
5.6 Entry Fees, Payoff, and Registration
A. The entry fee for competition per class at all USKRA, LLC Sanctioned Events will be
announced prior to the event.
5.7 Event Awards
A. In order to compete or receive awards in any class for a particular event, the participant
must be a Member of the United States Kart Racing Association.
B. Awards will be presented as follows:
1 to 4 competitors in class = 1st Place award to winner.
5 to 8 competitors in class = 1st and 2nd Place awards.
9 or more competitors in a class = 1st, 2nd, and 3rd Place awards.
C. Racers must attend 3 of 4 Seasonal Point Events to be eligible for end of year awards.
SECTION 6 - CHASSIS RULES
All competing karts must be inspected and approved by a Safety Tech Official prior to being
allowed to compete. Inspection of any kart does not guarantee or otherwise imply that the kart is
safe and free from defects. Responsibility for kart safety is the sole responsibility of the kart
owner, not USKRA, LLC. No expressed or implied warranty of safety shall result from publication
of, or compliance with these rules. Inspection is performed to provide a “visual” assurance that all
competitors are complying with the minimum safety rules required.
6.1 Tires
A. All USKRA classes are currently operating under an Open Slick Tire rule (Dirt and
Asphalt) for the 2014 Season unless noted otherwise.
B. Kart must have four (4) tires only; one located on each corner of the kart (RF, LF, RR, LR).
6.2 Wheel Rims
A. 5” or 6” diameter is legal.
B. Any aluminum wheel with a rim width up to 11” is legal.
6.3 Basic Kart Requirements
A. The kart must be in safe racing condition, and must meet the requirements of the USKRA,
LLC rules and regulations for its particular class. Safety items and chassis/body work
dimensions are subject to pre-race tech inspection and may be subject to post race tech
procedures. All changes to pre-race tech items must be approved by the Safety and/or
Technical Director.
6.4 Frame Construction
6.4.1 General Chassis Construction
A. Main Frame Rails are to be made from cold-rolled, round steel tubing, with:
B. 1” OD Minimum Main Rails with .078” Minimum Wall Thickness, or 1.25” OD Minimum
Main Rails with .060” Minimum Wall Thickness
C. 1.5” OD Maximum Main Frame Rails.
D. All frame rail connections are to be welded.
E. Chassis components must be secured, but may be designed so that the kart can be adjusted
while the kart is in motion during a race event.
F. The use of any type of suspension components is strictly prohibited.
6.4.2 Nerf Bars
A. Nerf Bars must be located between the front and rear tires on each side, and measure a
minimum of 24” long x 4” high.
B. The lower portion of the nerf bar assembly must be no lower than the bottom of the main
frame rails.
C. The upper portion of the nerf bar assembly as welded may not be more than 8 inches higher
than the bottom of the lower bar.
6.4.3 Front Bumper
A. Front bumper must incorporate an upper and lower tube design, and must be welded to
form one piece bumper.
B. Front vertical bracing must be constructed of a minimum of two horizontal bars, or one
“U”-shaped or oval hoop welded to the upper and lower main members of the front
bumper, in front of the pedal area.
C. The front bumper must be securely fastened to the kart frame in four places; 2 upper, 2
lower.
D. The maximum height of the front bumper shall be 10 inches minimum from ground level in
an “as- raced” condition.
6.4.4 Rear Bumper
A. Rear Bumper may incorporate a single or dual tube design, and must be welded to form a
one piece bumper.
B. Rear Bumper Width may not extend beyond the outside face of the rear tires.
C. The minimum height of the rear bumper shall be 10 inches minimum from ground level in
an “as- raced” condition.
6.5 Axle Assembly
A. Rear axle diameter: 1” minimum, 1-3/8” maximum; aluminum, steel, or titanium.
B. Hub and Axle Bearings must be of a Roller Ball or Roller Thrust design only.
C. Axle lock collars are not mandatory, but highly recommended.
D. For Speedway chassis, Hydraulic disc brakes are mandatory, and must brake the rear
wheels only. Steel rotors only. All bolts and fasteners are to be safety wired or cotter keyed.
Brakes must be fully operational at all times, including post-race. You may be required to
demonstrate the proper working condition of your kart’s brakes by any USKRA, LLC
official at any time.
E. A flat steel brake rotor protection plate (also known as a “Wolf plate”) between the seat and
brake rotor is mandatory on all karts, no exceptions.
6.6 Axle Hubs
6.6.1 Rear Hubs
A. Aluminum Hubs with steel or ceramic roller or thrust bearings.
B. Offset Chassis- Both drive wheels must be secured to the axle and cannot rotate
independent of each other.
C. Straight Rail Chassis- May utilize an optional ratcheting device on the rear axle.
6.6.2 Front Hubs
A. Aluminum Hubs with steel or ceramic roller or thrust bearings.
6.7 Seat
A. Seats must be constructed of Fiberglass, High-Impact plastic, or Carbon Fiber.
B. The seat must be positioned such that when the driver is seated, no part of the driver’s body
may be positioned outside of the main frame rails.
C. The following minimum distances are mandatory:
 1” clearance from brake rotor protection plate.


8” vertical seat clearance measured from the top of the axle.
No portion of the seat may be located below the bottom of the main frame rails.
6.8 Steering
A. The Steering Shaft must be made from a single piece of .625” minimum diameter solid
steel. Welding the steering wheel hub to the shaft is allowed.
B. The Steering Wheel must be secured to the shaft with a steel nut.
C. A “Quick Release” type steering wheel is mandatory on all Champ Karts and is optional on
all other chassis.
D. Tilt Steering Wheels are legal in all classes, and must be locked in position while on the
track.
E. All steering component bolts, and nuts, must be drilled and cotter keyed and/or safety
wired and must be of a minimum Grade 5 rating.
F. Steering Wheel must be a 2 or 3 spoke design made of tubular aluminum or steel with a
minimum outside diameter of 6” as measured across the smallest point.
G. Entirety of steering wheel may not have any sharp edges and must be of a closed design.
6.9 Fasteners and Bolt-On Weights
A. All bolts used to fasten weights to the kart must be double-nutted with at least one locking
type nut on top.
B. Any frame component that can be adjusted must be cotter keyed and/or safety wired.
C. All weights added to the kart must be securely fastened to the kart with a minimum
5/16-inch diameter bolt, or 5/16” welded steel stud.
D. Weights added to the seat area must be secured via at least one 5/16-inch diameter bolt for
every 5 pounds of lead, including lead sheet, and must be located above the bottom of the
main frame rails. Round head carriage bolts are recommended when attaching lead weights
to the seat, for safety and to avoid driver discomfort.
E. Loose weights contained between the seat and seat cover or driver are not allowed.
F. No weights may be attached to the competitor’s body, or contained within any of their
clothing.
G. All weights must be painted with white paint and have the kart number written on them.
6.10 Kart Width and Wheelbase
A. Kart Wheelbase is measured from the Rear Axle centerline to the Front Spindle centerline
(with the wheels pointed straight ahead) on each side.
B. 40.0-45.0 inches wheelbase
C. Kart Width shall be measured from outside tire sidewall face to opposite outside tire
sidewall face.
D. 28.0 –52.0 inches width
6.11 Overall Kart Length and Height
A. Overall Kart Length is measured “as-raced” in a horizontal plane from the outermost point
on the front extents of the kart, to the rearmost extents of the kart.
6.12 Champ Kart Length, Height, and General Specifications
A. Overall length may not exceed 95.0 inches maximum, as measured in a horizontal plane.
B. Roll cage overall width is 16.0 inches minimum as measured from outside to outside,
between any two uprights.
C. Roll cage overall height is 30.0 inches minimum. Height is to be measured vertically from
highest lateral cross bar centerline to main frame rail centerline. No part of the drivers
helmet is permitted to extend outside the top of the cage when the driver is seated.
D. Roll Cage construction bends shall be radiused with no sharp edges or corners.
E. A minimum 4-point, electric-welded roll cage made from minimum 1.125”: OD and
minimum .060” wall thickness cold-rolled steel tubing is required.
F. All four roll cage uprights must be welded to the main frame rails.
G. Rear uprights of the cage must be welded to the main frame side rails at a point located
behind the rear axle centerline.
H. Front uprights shall have no bends within 2 inches of the attachment point except at the left
rear as facing the front of the kart.
I. Front uprights must be welded to the main frame side rails at a point in front of the steering
wheel base mount point and behind the leading edge of the front tire. All uprights must
create an angle of no less than 45 degrees as measured from zero in a horizontal plane.
J. A shoulder harness mounting hoop is required and both must be welded together in place
securely between rear uprights.
K. An SFI 16.1 rated 5-point racing harness is mandatory, and harness must secure the driver
in the seat. A metal-to-metal harness fastener is mandatory. A minimum 3/16-inch thick by
2 inch square steel mounting plate must be welded to the frame and/or roll cage. 5/16”
minimum diameter mounting bolts must be lock-nutted and cotter-keyed. Arm restraints
are mandatory and must be attached to the harness per manufacturer’s recommendations.
L. When side protection bars are designed to be removable, a lower horizontal tube to support
the shoulder harness mounting loop is required and both must be welded together in place
securely between rear uprights.
M. The use of a headrest is optional, and the driver’s seat may have an integral headrest
incorporated into its design.
N. Side protection bars are mandatory, may be of a single or dual tube design, constructed
from a minimum .065” wall thickness and .750” minimum outside diameter, round steel
tubing, and must be attached to the front and rear uprights on each side of the roll cage.
Both ends of the side bars may be slip jointed, but must be securely bolted in place with no
less than a ¼” bolt and locknut.
O. Side protection bars should be located high enough to protect the driver from side impact
and in a position so as not to prevent driver egress, or obscure driver vision.
P. (Deleted)
Q. All roll cages that deviate in any way from the above description must receive approval
from the race director or tech inspector prior to be used in competition
6.13 Speedway and Road Course Kart Length and Height
A. Overall Length at any point may not exceed 77.0 inches maximum as measured in a
horizontal plane.
B. Overall Height at any point may not exceed 26.0 inches maximum. The entire kart must be
able to pass under a bar set parallel to ground level, 26.0 inches above ground level.
6.14 General Bodywork
A. The use of bodywork is highly recommended for safety. No pointed or sharp edges
allowed.
B. All bodywork components must be constructed of fiberglass, high-impact plastic, or
carbon fiber.
C. No bodywork component may extend past the rear bumper.
D. Bodywork must be confined within the area defined by the front and rear bumpers, and
may not extend beyond the maximum legal width of the kart.
E. Wedge style side panels and rear wings are legal on all non-restricted engine powered
karts, and must be constructed of high impact plastic or lexan ™. If a front panel (nose) is
utilized, there must be a 90 degree break with a 1” minimum lip bent down on the side
facing the driver, to protect the driver against injury in case of a front impact. All bodywork
must be securely fastened with no loose panels. No part of the bodywork may be higher
than 36” from the ground.
F. USKRA, LLC encourages innovative designs incorporating “ground effects” built into
bodywork in a safe manner.
G. Bodywork may in way impede driver ingress or egress, into or out of the kart.
H. No component of the bodywork may be adjusted or controlled in any way while the kart is
in motion.
I. If installed, Skirting devices must be constructed of a smooth, flexible, non-metallic
material.
J. Nose cones are mandatory in all classes. This is a safety concern, and is recommended to
aid in the protection of the driver’s feet.
K. Steering fairings are legal in all classes. It is the Driver and/or Legal Guardian’s
responsibility to ensure that if a steering fairing is used, it must be installed in such a
fashion so as to not hinder the driver’s visibility.
L. The use of a connecting strip from the nose cone or floor to steering fairing is legal.
M. Clearance between the steering wheel and any fairing is 2.0 inches minimum.
N. An installed Front Floor pan is mandatory.
O. Rear Belly pans are optional.
6.15 Champ Karts Only (Bodywork)
A. The use of a tail section is optional. If utilized,
 Minimum length is 14 inches
 Minimum width is 12 inches
 Minimum height is 16 inches
B. Champ Kart Nose bodywork is mandatory.
C. The driver’s compartment must always be fully accessible to allow for driver egress, and
extraction from the top, and from both sides.
D. Cage mounted aerodynamic bodyworks are permitted. Maximum width is 52.0 inches, or
the width of the lower bodywork, whichever is less.
E. Side panels may be flat; all other body components must have rounded edges and a
compound curve configuration.
SECTION 7- GENERAL RULES
A. Annual Kart Numbers will be assigned to members annually according to the sequence in
which they are reserved for each class. Numbers are assigned by driver preference on a
first-come, first-served basis. If the number is already in use, the driver must select a
different number, and has the sole responsibility for having those numbers on their kart
prior to any actual race on three sides of the kart, whether on number plates or bodywork.
B. All karts must be equipped with a fully functioning, positive acting throttle-return spring.
C. Data acquisition is legal in all classes for use during actual race.
D. All karts must have a minimum of 1/2” sprocket-to-ground clearance with the driver in the
kart.
E. 2-cycles may utilize #219 chain, clutch, and sprockets.
F. Radio communication between a competing driver and anyone else other than a USKRA,
LLC Official is illegal in all classes. Violators are subject to a loss of all seasonal points.
G. Rear view mirrors are prohibited in all classes.
H. Any dry, Disk or Shoe type engine-mounted clutch is legal in all classes except Predator
Claimer.
I. No Torque Converters or axle clutches allowed EXCEPT in the Open Class.
J. Third Bearing Supports, Jack Shafts, Girdle Kits, and Scatter Shrouds are legal in all
classes. The use of a Scatter Shroud is highly recommended. This is for safety, not
performance.
K. All new drivers are requested to display a visible “X” on a number panel located on the rear
bumper of their kart, and/or on the back of their helmet.
SECTION 8- ENGINE TECH GUIDELINES
8.1 Tech Official Responsibilities
A. The Engine Tech Official is to exercise extreme care in order to obtain accurate and
reliable results.
B. All engines will be teched per USKRA, LLC rules.
C. USKRA, LLC reserves the right to require any competitor to submit their engine for the
purpose of performing random engine tech at the discretion of USKRA, LLC after all
racing events are completed by the competitor for that day.
D. All engines must meet all of the listed specifications to be considered legal.
8.2 Impounding and Inspection
A. USKRA, LLC does not impound engines past the end of that race day’s tech.
B. Engine owners are recommended to engrave their personal identification info onto the
front of their engine’s block.
C. Engines must be submitted for inspection immediately following their race(s), and picked
up by their owner before the Tech area is closed for that day.
D. Absolutely NO cast aluminum flywheels! If you are caught using a cast aluminum
flywheel, you will immediately be banned from racing in any sanctioned USKRA, LLC
event for a mandatory one-year period from the date of the infraction.
8.3 Engine Fasteners
A. All Engine Fasteners must remain in their original location, and cannot be altered in any
way to achieve a performance gain. Any attempt to relocate any bolt location or re-size any
fastener on the block (i.e. Cylinder head, exhaust, or carburetor) to produce a performance
gain is considered illegal and is grounds for intentional disqualification.
8.4 Fuel Systems and Fuel Testing
A. Aluminum, stainless steel, and polymer fuel tanks are legal.
B. Fuel is subject to sample testing at any time from pre-race until the time that the engine and
kart are both released from post-race tech.
C. Fuel samples may be taken from any point from the fuel tank to the carburetor.
D. If your fuel is required to be tested you may also be required to sign a letter of authenticity,
and sign/seal the sample. Fuel may be tested at the track, or later at our discretion by a
chemical analysis firm.
E. Refusal to voluntarily submit a fuel sample is deemed an intentional disqualification and is
punishable as such.
F. Fuel tank caps must vent and are subject to inspection.
G. No pressurized fuel tanks/systems allowed in any class, with the exception of Nitrous
Oxide in the Outlaws class.
SECTION 9- CLASS TECHNICAL SPECIFICATIONS
9.0 General Specifications
A. Competitors may use any approved, commercially available engine as listed in each
section.
B. Promulgation of engines will be reviewed annually, or as deemed beneficial by USKRA,
LLC.
C. All equipment used in any race is subject to post race inspection.
D. Naturally aspirated engines only. No supercharging, turbocharging, or nitrous oxide
systems permitted except in the Outlaw class. Air may not be admitted to the cylinder in
any other manner than through the carburetor venturi in any class.
E. Modifying the engine or exhaust system to evacuate exhaust gasses is illegal except as
noted.
F. Mufflers are required in all classes, at all events, unless noted otherwise.
G. No cool-down period before tech. Engine tech may be performed at any time.
H. Carb or manifold must bolt to block. No welding of induction or exhaust system directly to
block.
I. The use of drilled bolts may be required on the induction system to block (carb or
manifold) to permit the installation of a safety seal prior to competing in any USKRA, LLC
event. Alternatively, the carburetor may paint-marked to be teched. If a carburetor is
changed, it must go through technical inspection again prior to competing.
J. In ALL 4-cycle classes, attachment of the crankcase sidecover may be performed in any
way necessary to secure the cover (ie. drilled bolts, studs, sealant) BUT sidecover MUST
still be removable for tech. This change is being made to prevent oil loss and engine
damage, and does not constitute a performance modification.
9.1 Youth Restricted Classes
9.1.1 Restricted Classes and Kart + Driver Weights are as follows
A.
Novice- Restricted Modified Stock, 190lbs
B.
Rookie- Restricted Modified Stock, 220lbs
C.
Sportsman- Restricted Modified Stock, 250lbs
D.
Junior- Restricted Modified Stock, 280lbs
9.1.2 Youth Champ classes:
A.
Sportsman Champ, 255lbs, Restricted Modified Stock Sportsman engine
B.
Junior Champ, 315lbs, Restricted Modified Stock Junior engine
9.1.3 The USKRA, LLC Restricted Modified Stock classes are open to the following engines:
A. Clone, Briggs Flathead, Briggs Animal.
The rules are broken down for each type of engine as follows:
9.2.0 USKRA Pro Stock Clone (Added 5-1-2014)
1. Engine base design must begin as a 6.5hp single cylinder, 2 valve OHV design (No OHC
engines).
2. All parts must be OEM for engine used unless specifically stated otherwise.
3. All gaskets are non-tech items.
4. The use of a Top Plate is legal, but not mandatory.
5. Throttle linkage is a non-tech item.
6. Sheet metal may be painted, powder coated, or hydro-dipped. All cylinder and flywheel
sheet metal to be installed. The attachment of an auxiliary fuel pump to the blower housing
sheet metal is permitted.
7. Fasteners (bolts, washers, nuts, screws) are non-tech items unless noted, however they
must be of original size (no undersizing or oversizing) and of such a design as to not
produce a performance enhancement.
8. (OMIT)
9. Pull Starter assembly must be factory unit, securely installed. Starter assembly may be
rotated to allow easy access to start engine. Broken starter cords may be replaced with
non-factory cord.
10. Low Oil Sensor and Kill Switch may be removed, and any associated holes plugged.
11. Flywheel: Must be unaltered as produced. Any Billet steel or Billet aluminum flywheel
weighing a minimum of 3.3 lbs. is permitted. No cast flywheels allowed. Flywheel must
have fins. May use any timing key, or no key. Non-Tech item.
12. Block bore may not exceed 2.685" when measured at any point. Block only may be welded
for repairs, and may not be done in such a way as to produce or conceal a performance
enhancing alteration.
Oil drain hole between the lifters is a non-tech item.
13. Crankshaft: Factory stock OEM or Original Honda permitted. Maximum legal stroke is
2.1330".
No lightening, polishing, addition or removal of material allowed except minor polishing
and cleanup of crankshaft bearing and connecting rod journals. Main journal diameter must
measure from 1.168" minimum to
1.180" maximum.
14. Cylinder Head: Must be OEM for engine used. No hemi heads.
Block and Cylinder Head may be decked.
Minimum cc for engine is 26.0cc
Ports: Intake and Exhaust ports must be factory stock.
Combustion Chamber: No altering of the combustion chamber is permitted. Must be
factory stock.
Up to 3 angles are allowed on the valve seats. From top to bottom as viewed from the
combustion chamber, angles are as follows: 45/30/60.
Sinking of valves below the combustion chamber floor is not permitted.
Intake Seat: Maximum ID is .900"
Exhaust Seat: Maximum ID is .865"
Depth of the area between the valve seats may not vary by more than .005" when measured
at any point.
Cylinder Head Gasket: Non-tech item. Sealer allowed.
15. Rocker Arm Assemblies: Factory OEM stock only. Contact area is non-tech, otherwise
rocker arms must remain as produced at factory.
16. Valves: Minimum weight: 21g
Valve angle: 45 degrees
Intake Valve minimum head OD: .975"
Exhaust Valve minimum head OD: .940"
Clone or Stainless replacement valves utilizing stock retainers and keepers.
17. Valve Springs- Any single wound non-titanium valve spring permitted.
Maximum Valve Spring Wire Diameter: Non-tech
Valve Spring Retainers must be unaltered stock OEM.
Lash Cap mandatory and allowed on Exhaust side only.
valve Stem Seal allowed, maximum one per valve.
18. Factory Stock piston: 1.920" minimum length.
Compression Height when measured from top of piston to top of wrist pin may not exceed
.580" maximum.
Arrow on piston must point towards valves. When engine short block is teched "as
assembled", no part of the piston may "pop-up" above the surface of the block deck, when
measured at any point.
Factory Stock Wrist Pin: minimum length 2.100", .550" maximum inside dimension.
Piston Rings: May be surfaced, and End Gap may be cut or filed, must meet listed
specifications.
Piston Top Ring: .115" maximum width, .060" maximum thickness, no tech on end gap
Piston 2nd Ring: .115" maximum width, .060" maximum thickness, .040" maximum end
gap as installed
Oil Ring (Rails and Expander): Ends may be cut/filed to achieve desired gap.
19. Connecting Rod: may be Cast Factory Stock part, Old or New Style (Cast
Vacuum-Forged), or Billet rod (optional). Any length from stock length to +.030" is legal.
No tech on oil hole(s). If a billet rod is used, the babbits are non-tech items, and rod bolts
for all types of rods must be steel, but are otherwise non-tech items.
20. Camshaft: Must be stock core with fully functional, unaltered compression release.
21. Base Circle (both lobes): .860" minimum to .870" maximum.
No tech on visual appearance of lobe surfaces. Polishing of lobe surfaces is legal, but lobe
surface must remain flat.
22. NOTE: Camshaft requirements are based upon the design of the Dyno CL-1* and CL-2,
and BSP-1, BSP-2, and BSP-3 series camshafts, HOWEVER no matter what make or
manufacture of cams is used, camshaft must be within ALL specifications as listed.
23. Camshaft DURATION Specifications:
INTAKE Maximum 221 degrees @ .050" Lift
INTAKE Maximum 88 degrees @ .200" Lift
EXHAUST Maximum 224 degrees @ .050" Lift
EXHAUST Maximum 99 degrees @ .200" Lift
24. Camshaft MAXIMUM LIFT Specifications:
INTAKE (measured at Valve Spring Retainer) maximum lift .238"
EXHAUST (measured at Valve Spring Retainer) maximum lift .242"
INTAKE (measured at Camshaft) maximum lift .225"
EXHAUST (measured at Camshaft) maximum lift .232"
INTAKE (measured at Push Rod) maximum lift .215"
EXHAUST (measured at Push Rod) maximum lift .222"
25. Air Filter Adapter: Maximum Length 1.5"
26. Air Filter: Non-Tech item
27. Air Filter Pre-Filter: Non-Tech item
28. Carburetor: Huayi or Rui*ing only. Factory choke must be installed and functional. A
separate device may be utilized to hold the choke in position. Carburetor Venturi is .615"
no-Go. Carburetor Rear Bore .751"
diameter No-Go x .750" maximum depth.
29. Rear carburetor gasket surface may not be altered.
30. Carburetor mounting studs may not be bent.
31. Carburetor Emulsion Tube: Minimum length 1.090" , .066" ID No-Go. Maximum 4 holes
in bottom between collars and size is .036" No-Go. Maximum 20 top holes.
32. Carburetor Throttle Shaft: .115" minimum thickness. Throttle Shaft Stop Arm may be
filed.
33. Carburetor Throttle Shaft Butterfly: .037" minimum thickness.
34. Carburetor Throttle Shaft Butterfly Screw is a non-tech item
35. Phenolic Spacer: Factory OEM black phenolic spacer, .265" minimum thickness across
entire gasket surface as measured at any point. Minor de-burring of phenolic spacer venturi
to remove venturi flashing is permitted, and no visual tech on venturi.
36. Entirety of Induction System is subject to being checked for proper seal. No air is to be
admitted to the engine except through the carburetor venturi. Engine may be checked for
improper admittance of air at any
time.
37. Auxiliary Fuel Pump: A single, vacuum-actuated, single fuel outlet auxiliary fuel pump
may be used, and must be pulsed from either the crankcase or valve cover. Auxiliary fuel
pump may utilize an attachment to a top plate, to the flywheel cover sheet metal, or may be
"free-hung" as desired.
38. Fuel- Gasoline, up to and inclding 92 octane. Ethanol-free legal.
39. Fuel tank must be mounted in the front floor pan area.
40. Lifters: must be stock OEM. Minimum Weight is 18g each.
41. Push Rods: must be stock OEM. Maximum Length is 5.285". Minimum Weight is 9g each.
42. Coil: Must be stock OEM or stock replacement part, mounted in factory position, and
unaltered as produced at the factory except resistor may be removed, and plug boot is a
non-tech item.
43. Spark Plug: Non-Tech item
44. Header- Any ID single inlet/single outlet design header allowed up to 23" in length. Header
may be swaged, or have welded stages. Header may be coated or painted, internally and/or
externally. Header may not extend
beyond confines of kart.
Header must be safety wired or double-nutted. If any part of a header breaks or comes loose
and becomes separated from the engine, it is a disqualification, no exceptions.
Header may be sealed to the cylinder head with a gasket, sealant, or both.
45. Header heat wrap or sleeve is legal and recommended.
46. Bracing from the engine or an attached part (ie. chain guard, motor mount) to secure the
exhaust assembly (header/muffler) in place is mandatory.
47. Muffler must be an RLV B91 (#4104) or RLV Mini muffler (#4117). RLV B91-XL
(#4106) "square hole" muffler not allowed. All baffles must be in place. Maximum hole
diameter is .125" Safety wiring the muffler through the baffle is legal. Muffler must be
clamped securely to the header with no
air gap. If a muffler becomes separated from the header, it is a disqualification, no
exceptions.
48. Clutch- Any dry disc(s) or shoe type clutch allowed; must be mounted directly on
crankshaft.
9.2.1 RESTRICTED MODIFIED STOCK (Clone)
1.
Fuel- Methanol; must pass hydrometer test.
2.
Base Engine must be a Clone 6.5 hp, non-overhead cam engine. No Hondas.
3.
Bolts and Studs must be factory stock, but may be drilled and safety wired. Thread repair
inserts are legal. The use of bolts instead of studs on the exhaust is permitted, and it is
advisable to use drilled bolts so that they can be safety wired to prevent loss.
4.
Gaskets are non-tech items.
5.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
6.
Block Cylinder Bore is 2.725″ maximum.
7.
Block Deck- may be decked, piston pop-up is non-tech.
8.
O-ringing the block deck is not legal.
9.
Block may be welded for repairs and strengthening only. No performance-enhancing
weldments allowed.
10.
Flywheel- Any SFI approved flywheel, including PVL. No factory stock flywheels unless
SFI approved.
11.
A flywheel bracket may be utilized to lower the coil when using a 3HP flywheel.
12.
Block coil posts are non-tech.
13.
The factory pull rope starter is legal. An optional electric starter nut is allowed. A flywheel
screen/guard shall be required in place of the pull starter to prevent contact with the
flywheel if the electric starter nut is utilized and the original starter is removed, for safety
reasons.
14.
Ignition Coil must be factory stock clone part.
15.
Ignition Kill Switch may be removed. If removed, hole must be plugged.
16.
Low Level Oil Sensor/Switch may be removed. If removed, hole must be plugged.
17.
Valve Cover must be factory stock. A pulsing connection is allowed. A spacer to allow for
rocker arms clearance is allowed.
18.
Cylinder Head- Clone Head only. No Honda, Hemi, or Billet heads allowed.
19.
Cylinder Head Ports and Port Faces- must be factory stock; no modifications allowed.
20.
Cylinder Head Gasket Surface may be machined to any depth.
21.
Cylinder Head Combustion Chamber must be stock. No modifications allowed.
22.
Cylinder Head Welding is allowed only to repair rocker stud damage.
23.
Cylinder Head Gasket is a non-tech item.
24.
Rocker Arms may be any ratio, but must tech within cam rules. Rocker Arms may be
stamped, or Champion (New or Old style). No billet. Welding is permitted to strengthen
rocker arms.
25.
Valves may be Clone, Honda, or Stock size and style stainless only.
26.
Exhaust Valve Head OD must be .935″-.950″
27.
Intake Valve Head OD must be .975″-.990″
28.
No tech on Valve Face Angles.
29.
Exhaust Valve Seat ID .880″ maximum
30.
Intake Valve Seat ID .910″ maximum
31.
Valve Seat Angles are non-tech.
32.
Valve Stem Diameter must be .214″-.218″.
33.
Each valve must weight a minimum of 20 grams.
34.
Valve Heads must both be located above combustion chamber floor (no sinking).
35.
Valve Springs- Single only. Must be magnetic. No titanium. No tech on size.
36.
Valve Spring Seats may be machined.
37.
Valve Spring Shims are allowed, and are non-tech items.
38.
Valve Spring Retainers and Keepers are non-tech items, except no titanium allowed.
39.
In Restricted Classes, Restrictor Plate may be teched with dial calipers or a no-go gauge,
the plate size may not exceed the size for the class of engine raced. Entirety of plate must
be anodized. Restrictor Plates must be factory stock as received from ARC. No altering
allowed. No bends, relocation of hole, laser cutting, deep scratches that would alter flow,
no funneling of hole. FLAT plates only.
40.
Novice- Clone Red .375″
41.
Rookie- Clone Green .425″
42.
Sportsman- Clone Purple .500″
43.
Junior- Clone Blue .550″
44.
Carburetor body must be Huayi or Ruiing only, and must be bare metal finish (no paint or
coating).
45.
Carburetor Bore maximum is .625″. Size may be checked with internal dial calipers to
ensure compliance.
46.
Carburetor Emulsion Tube is a non-tech item.
47.
Carburetor Throttle Shaft is a non-tech item.
48.
Carburetor Butterfly screw is non-tech so long as it secures the butterfly to the throttle
shaft, and is removable.
49.
Carburetor Butterfly minimum thickness is .035″, and must be removable.
50.
Black Phenolic Spacer must be in place. Blending and refinishing of the venturi/port hole is
legal.
51.
Any single fuel pump allowed. May be pulsed from the block, side cover, or valve cover.
52.
Side Cover (PTO side) must be factory stock casting. Connections may be added for
venting, or to pulse the fuel pump. The sidecover on all Modified Stock engines may be
vented to an oil capture device, and may NOT be vented to the atmosphere without first
being routed into a "catch can" type device.
53.
Factory Clone Crankshaft or Original Honda, stroke 2.113-2.133″ with no modifications
allowed. Allowance only for factory clean-up (no performance-enhancing modifications
allowed).
54.
Crankshaft Connecting Rod Journal must measure between 1.182″-1.166″.
55.
Crankshaft Bearings- Aftermarket steel bearings allowed. No ceramic or self-aligning
bearings allowed.
56.
Crankshaft Gear must be factory stock, and may be welded to the crankshaft.
57.
Connecting Rod may be any length billet aluminum rod with babbit inserts.
58.
Piston- Honda flat top legal, and factory clone piston legal and may have the dish milled
off. No domed pistons allowed; piston top must be flat. Piston top may be cut flat,
otherwise piston must remain factory stock.
59.
Piston Rings must be of stock quantity and configuration. Rings may be trued. Stock style
low tension rings may be used.
60.
Piston Pin is a non-tech item.
61.
Valve Lifters must be stock with round, flat base; no rollers.
62.
Camshaft must be stock core, but may be welded and heat treated.
63.
Camshaft (Restricted classes)- Measured at the retainer “as-raced” (with lash) .275″
maximum lift, 230 degrees @ .050″, 110 degrees duration @ 200″,
64.
Pushrods are non-tech items.
65.
Pushrod Guide Plate is a non-tech item.
66.
Any Exhaust Header allowed as long as it fits within the confines of the kart.
67.
Muffler must be an unaltered RLV #4104. It is advisable to safety wire the muffler to the
engine.
68.
Floor mounted fuel tank only
69.
Dry disc or shoe clutches only
9.2.2 RESTRICTED MODIFIED STOCK (Flathead 5HP Briggs)
1.
Fuel- Methanol; must pass hydrometer test.
2.
All stock sheet metal must be installed.
3.
Gaskets are non-tech items.
4.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
5.
An SAE approved billet flywheel is mandatory. A flywheel bracket may be utilized to
lower the coil when using a 3HP flywheel. In lieu of a pull starter, the flywheel may utilize
an electric starter nut for use with an electric starter (hand held). A flywheel washer is
required in all cases. Flywheel key non-tech item, and does not have to be installed. Block
coil posts are non-tech.
6.
Cylinder Head must be original Briggs or Burris reproduction; no relocation or enlarging
of bolt holes. May be decked. May be milled flat inside combustion chamber; no fire slots.
Valve pockets may be milled to accommodate cam lift at valves, but no milling or
otherwise altering side walls inside head. No welding permitted on cylinder head.
7.
Block must be original Briggs flathead 5hp. Welding permitted to repair and brace only.
No welding to enhance performance. Porting allowed but must be below the seat and inside
the port face; no addition of material inside or outside port. Valve chamber may be back
faced to secure upper valve spring retainer.
8.
Maximum Bore: 2.6325″
9.
Angle milling of the block deck is permitted.
10.
No tech on piston popup.
11.
Piston must be flat top (no domes or dishes), and may be manufactured by Briggs or
aftermarket. No tech on piston pin, pin height, or rings.
12.
Coil must be OEM Briggs.
13.
Spark Plug is a non-tech item.
14.
Crankshaft: Must be Briggs style cast crankshaft, no polishing or lightening.
15.
Maximum Stroke: 2.457″
16.
Crankshaft Bearings are non-tech items
17.
Connecting rod may be billet or stock cast.
18.
No tech on rod length.
19.
Camshaft Lift Max “as-raced” (with lash): .240″
20.
Lifters may be stock, or stock style billet. Clearancing is allowed in lifter galley.
21.
Carb may be stock OEM flathead 5hp carb with dual Briggs OEM style pickup tubes and
removable jet.
22.
Maximum Carb Bore: .725″, no sleeving,
23.
OR may be Tillotson with .625″ max bore, auxiliary fuel pump and intake manifold legal
with Tillotson carb.
24.
Restrictor Plates must be factory stock as received from ARC or Horstman. No altering
allowed. No bends, relocation of hole, laser cutting, deep scratches that would alter flow,
no funneling of hole. FLAT plates only.
25.
Rookie- Flathead Purple .425″
26.
Sportsman- Flathead Turquoise .500″
27.
Junior- Flathead Gold .575″
28.
No welding inside ports. No changing port face angles; port face must be stock.
29.
Any single wound, non-titanium valve spring; keepers and retainers are non-tech items.
30.
Valves must be stock materials, no titanium.
31.
Intake port Max size: .900″
32.
Intake Seat Max ID: 1.010″
33.
Intake Valve Head Minimum OD: 1.110″
34.
Intake Valve Stem Minimum OD: .245″
35.
Exhaust port Max size:1.010″
36.
Exhaust Seat Max ID: .885″
37.
Exhaust Valve Head Minimum OD: .985″
38.
Exhaust Valve Stem Minimum OD: .245″
39.
A Header is required. The header pipe must be braced, and must be located within the
confines of the kart. The use of
40.
A heat wrap or sleeve is mandatory and must cover the majority of the header; wrap/sleeve
may cover muffler, but muffler must be removable. Ceramic Header coatings are legal.
41.
An RLV B91XL or B91MO muffler is required. Muffler is to be attached to header in a
safe manner with a clamp. Muffler may not be welded to header and must be removable.
Muffler must still be attached to the header when teched.
42.
Welding is permitted to the block for repairs and may not be done in such a way as to
provide a performance enhancing alteration.
43.
Bolts, screws, washers, etc. are non-tech items.
44.
ALL engine parts not mentioned are non-tech items except that they must be Briggs 5 HP
parts with exception of flywheel screen guard.
9.2.3 RESTRICTED MODIFIED STOCK (Animal)
1.
Fuel- Methanol; must pass hydrometer test.
2.
Thread repair inserts are legal unless noted otherwise.
3.
Gaskets are non-tech items.
4.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
5.
Base engine may be Animal, Gas Animal, or LO206 as long as it meets specifications
listed.
6.
Engine block- no addition or subtractions of metal or any substance to the
7.
inside or outside of the cylinder block unless noted. Angle milling or peak decking IS
allowed.
8.
Side Cover (PTO side) must be factory stock casting. Connections may be added for
venting, or to pulse the fuel pump.
9.
Block may be welded for repairs and strengthening only. No performance-enhancing
weldments allowed.
10.
Block coil posts are non-tech.
11.
Ignition Kill Switch and Low Level Oil Sensor/Switch are optional. If removed, hole must
be plugged.
12.
Oil breather must vent to a catch container. An oil overflow catch system is mandatory.
Overflow tube must run from the crankcase breather to a catch container.
13.
Carburetor Overflow- If the carb utilized is fitted with an overflow it must be vented to an
oil catch container. The catch-container must be vented to atmosphere.
14.
An auxiliary fuel pump may be used.
15.
All sheet metal- Cooling Shrouds, Covers and Blower Housings must be installed but are
otherwise non-tech items.
16.
Factory bolts, studs only. May be drilled and safety wired.
17.
Restrictor Plates must be factory stock as received from ARC or Horstman. No altering
allowed.
18.
In Restricted Classes, Restrictor Plate may be teched with dial calipers or a no-go gauge,
the plate size may not exceed the size for the class of engine raced. Entirety of plate must
be anodized. Restrictor Plates must be factory stock as received from ARC or Horstman.
No altering allowed. No bends, relocation of hole, laser cutting, deep scratches that would
alter flow, no funneling of hole. FLAT plates only.
19.
Novice- Clone only, Red .375″
20.
Rookie- Animal Purple 3 hole .225″
21.
Sportsman- Animal Blue 2 Hole .275″ / .325″
22.
Junior- Animal Gold 3 hole .312″
23.
Carburetor may be type as supplied on Animal/LO206 from factory, OR may be Tillotson
with .625″ max bore, auxiliary fuel pump and intake manifold legal with Tillotson carb.
24.
Animal Carburetor specifications: Venturi Measurement: Vertical: .795″ maximum.
25.
Horizontal: .615″ maximum at widest part
26.
Horizontal: .605″ maximum at narrowest part.
27.
Throttle bore .875″ maximum diameter
28.
Intake Port Maximum diameter .920″
29.
Exhaust Port maximum .980″
30.
Valve Cover must be factory stock. A pulsing connection is allowed.
31.
Cylinder Head Ports and Port Faces- must be factory stock; no modifications allowed.
32.
Cylinder Head Gasket Surface may be machined to any depth.
33.
Cylinder Head Combustion Chamber must be stock. No modifications allowed.
34.
Cylinder Head Welding is allowed only to repair rocker stud damage.
35.
Cylinder Head Gasket is a non-tech item.
36.
Intake valve
37.
valve stem minimum diameter .245″
38.
valve head minimum diameter 1.055″
39.
valve seat maximum inside diameter .975″
40.
Exhaust valve
41.
valve stem diameter .245″
42.
valve head minimum diameter.935″
43.
valve seat maximum inside diameter .850″
44.
No tech on Valve Face Angles.
45.
Valve Seat Angles are non-tech.
46.
Each valve must weight a minimum of 28 grams.
47.
Valve Heads must both be located above combustion chamber floor (no sinking).
48.
Valve Spring Seats may be machined.
49.
Valve Spring Shims are allowed, and are non-tech items.
50.
Pushrods are non-tech items.
51.
Valve Springs- any single wound, non-titanium valve spring is allowed.
52.
Valve Spring Retainers and Keepers are non-tech items, except no titanium allowed.
53.
Rocker arms must be B&S part #691230 (US) or #797443 (metric). Rocker Arms may be
any ratio, but must tech within cam rules. Welding is permitted to strengthen rocker arms.
54.
Rocker studs must be stock, unaltered stock B&S part #694544 (US) or #797441 (metric)
and in stock location.
55.
Rocker Ball and Rocker arm stud plates are non-tech items.
56.
Push rods are non-tech items
57.
No tech on piston pop up.
58.
Cylinder bore 2.725″ maximum
59.
Crankshaft stroke 2.205” maximum
60.
Maximum Intake and Exhaust is .255″. Valve Lift is checked from the top of the valve
spring retainer “as-raced” (with lash).
61.
Any unaltered SAE approved Flywheel is permitted. A coil bracket is permitted to alter
coil location.
62.
Ignition System- any non-battery fired ignition system is permitted
63.
Crankcase and cover must be B&S stock, and may have vents installed.
64.
Clutch- any dry disc or shoe type clutch is permitted.
65.
The use of a Chain Guard is mandatory.
66.
The factory pull rope starter is legal. An optional electric starter nut is allowed. A flywheel
screen/guard shall be required in place of the pull starter to prevent contact with the
flywheel if the electric starter nut is utilized and the original starter is removed, for safety
reasons.
67.
Exhaust Header is non-tech, but must be installed in a safe manner within the confines of
the kart, with the muffler installed.
68.
A Header support brace is mandatory. Heli-coiling of the exhaust is allowed.
69.
At least one bolt or nut must be safety wired on the cylinder head and exhaust header.
70.
Muffler must be an unaltered RLV B91XL (part number 4104) with round baffle holes
only. Safety wiring of the silencer to header is recommended.
71.
It is recommended for safety to wrap the exhaust header and muffler with a heat-protective
sleeve or wrap.
72.
Any single fuel pump allowed. May be pulsed from the block, side cover, or valve cover.
73.
Crankshaft Bearings- Aftermarket steel bearings allowed. No ceramic or self-aligning
bearings allowed.
74.
Crankshaft Gear must be factory stock, and may be welded to the crankshaft.
75.
Connecting Rod may be any length billet aluminum rod with babbit inserts.
76.
Piston- must remain factory stock.
77.
Piston Rings must be of stock quantity and configuration. Rings may be trued. Stock style
low tension rings may be used.
78.
Piston Pin is a non-tech item.
79.
Valve Lifters must be stock with round, flat base; no rollers.
80.
Camshaft must be stock core, but may be welded and heat treated.
81.
Camshaft (Restricted classes)- Measured at the retainer “as-raced” (with lash) .255″
maximum lift, 220 degrees @ .050″, 110 degrees duration @ 200″
82.
Floor mounted fuel tank only
9.3 Adult Modified Stock Classes
9.3.0.1 The USKRA, LLC Adult (Non-Restricted) Modified Stock classes are open to the
following engines: Clone, Briggs Flathead, Briggs Animal.
9.3.0.2 Adult Modified Stock Classes and Kart + Driver Weights are as follows:
Adult Flat Kart classes:
A.
Ultra Light 300lbs
B.
Light 330lbs
C.
Medium 360lbs
D.
Heavy 390lbs
E.
Super Heavy 420lbs
F.
Sumo 450lbs
Adult Champ classes (includes Clone, Flathead, Animal)
G.
Senior Champ 425lbs
H.
Sumo Champ 475lbs
The rules are broken down for each type of engine as follows:
9.3.1 MODIFIED STOCK (Clone)
1.
Fuel- Methanol; must pass hydrometer test.
2.
Base Engine must be a Clone 6.5 hp, non-overhead cam engine. No Hondas.
3.
Bolts and Studs must be factory stock, but may be drilled and safety wired. Thread repair
inserts are legal. The use of bolts instead of studs on the exhaust is permitted, and it is
advisable to use drilled bolts so that they can be safety wired to prevent loss.
4.
Gaskets are non-tech items.
5.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
6.
Block Cylinder Bore is 2.725″ maximum.
7.
Block Deck- may be decked, piston pop-up is non-tech.
8.
O-ringing the block deck is not legal.
9.
Block may be welded for repairs and strengthening only. No performance-enhancing
weldments allowed.
10.
Flywheel- Any SFI approved flywheel, including PVL. No factory stock flywheels unless
SFI approved. A flywheel bracket may be utilized to lower the coil when using a 3HP
flywheel. Block coil posts are non-tech.
11.
The factory pull rope starter is legal. An optional electric starter nut is allowed. A flywheel
screen/guard shall be required in place of the pull starter to prevent contact with the
flywheel if the electric starter nut is utilized and the original starter is removed, for safety
reasons.
12.
Ignition Coil must be factory stock clone part.
13.
Ignition Kill Switch may be removed. If removed, hole must be plugged.
14.
Low Level Oil Sensor/Switch may be removed. If removed, hole must be plugged.
15.
Valve Cover must be factory stock. A pulsing connection is allowed. A spacer to allow for
rocker arms clearance is allowed.
16.
Cylinder Head- Clone Head only. No Honda, Hemi, or Billet heads allowed.
17.
Cylinder Head Ports and Port Faces- must be factory stock; no modifications allowed.
18.
Cylinder Head Gasket Surface may be machined to any depth.
19.
Cylinder Head Combustion Chamber must be stock. No modifications allowed.
20.
Cylinder Head Welding is allowed only to repair rocker stud damage.
21.
Cylinder Head Gasket is a non-tech item.
22.
Rocker Arms may be any ratio, but must tech within cam rules. Rocker Arms may be
stamped, or Champion (New or Old style). No billet. Welding is permitted to strengthen
rocker arms.
23.
Valves may be Clone, Honda, or Stock size and style stainless only.
24.
Exhaust Valve Head OD must be .935″-.950″
25.
Intake Valve Head OD must be .975″-.990″
26.
No tech on Valve Face Angles.
27.
Exhaust Valve Seat ID .880″ maximum
28.
Intake Valve Seat ID .910″ maximum
29.
Valve Seat Angles are non-tech.
30.
Valve Stem Diameter must be .214″-.218″.
31.
Each valve must weight a minimum of 20 grams.
32.
Valve Heads must both be located above combustion chamber floor (no sinking).
33.
Valve Springs- Single only. Must be magnetic. No titanium. No tech on size.
34.
Valve Spring Seats may be machined.
35.
Valve Spring Shims are allowed, and are non-tech items.
36.
Valve Spring Retainers and Keepers are non-tech items.
37.
Carburetor body must be Huayi or Ruiing only, and must be bare metal finish (no paint or
coating).
38.
Carburetor Bore maximum is .625″. Size may be checked with internal dial calipers to
ensure compliance.
39.
Carburetor Emulsion Tube is a non-tech item.
40.
Carburetor Throttle Shaft is a non-tech item.
41.
Carburetor Butterfly screw is non-tech so long as it secures the butterfly to the throttle
shaft, and is removable.
42.
Carburetor Butterfly minimum thickness is .035″, and must be removable.
43.
Black Phenolic Spacer must be in place. Blending and refinishing of the venturi/port hole is
legal.
44.
Any single fuel pump allowed. May be pulsed from the block, side cover, or valve cover.
45.
Side Cover (PTO side) must be factory stock casting. Connections may be added for
venting, or to pulse the fuel pump.
46.
Factory Clone Crankshaft or Original Honda, stroke 2.113-2.133″ with no modifications
allowed. Allowance only for factory clean-up (no performance-enhancing modifications
allowed).
47.
Crankshaft Connecting Rod Journal must measure between 1.182″-1.166″.
48.
Crankshaft Bearings- Aftermarket steel bearings allowed. No ceramic or self-aligning
bearings allowed.
49.
Crankshaft Gear must be factory stock, and may be welded to the crankshaft.
50.
Connecting Rod may be any length billet aluminum rod with babbit inserts.
51.
Piston- Honda flat top legal, and factory clone piston legal and may have the dish milled
off. No domed pistons allowed; piston top must be flat. Piston top may be cut flat,
otherwise piston must remain factory stock.
52.
Piston Rings must be of stock quantity and configuration. Rings may be trued. Stock style
low tension rings may be used.
53.
Piston Pin is a non-tech item.
54.
Valve Lifters must be stock with round, flat base; no rollers.
55.
Camshaft must be stock core, but may be welded and heat treated.
56.
Camshaft (Non-Restricted classes)- Measured at the retainer “as-raced” (with lash) .280″
maximum lift, 280 degrees @ .050″, 160 degrees duration @ 200″,
57.
Pushrods are non-tech items.
58.
Pushrod Guide Plate is a non-tech item.
59.
Any Exhaust Header allowed as long as it fits within the confines of the kart.
60.
Muffler must be an unaltered RLV #4104. It is advisable to safety wire the muffler to the
engine.
61.
Floor mounted fuel tank only
62.
Dry disc or shoe clutches only
9.3.2 MODIFIED STOCK (Flathead 5HP Briggs)
1.
Fuel- Methanol; must pass hydrometer test.
2.
All stock sheet metal must be installed.
3.
Gaskets are non-tech items.
4.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
5.
An SAE approved billet flywheel is mandatory. A flywheel bracket may be utilized to
lower the coil when using a 3HP flywheel. In lieu of a pull starter, the flywheel may utilize
an electric starter nut for use with an electric starter (hand held). A flywheel washer is
required in all cases. Flywheel key non-tech item, and does not have to be
6.
installed. Block coil posts are non-tech.
7.
Cylinder Head must be original Briggs or Burris reproduction; no relocation or enlarging
of bolt holes. May be decked. May be milled flat inside combustion chamber; no fire slots.
Valve pockets may be milled to accommodate cam lift at valves, but no milling or
otherwise altering side walls inside head. No welding permitted on cylinder head.
8.
Block must be original Briggs flathead 5hp. Welding permitted to repair and brace only.
No welding to enhance performance. Porting allowed but must be below the seat and inside
the port face; no addition of material inside or outside port. Valve chamber may be back
faced to secure upper valve spring retainer.
9.
Maximum Bore: 2.6325″
10.
Angle milling of the block deck is permitted.
11.
No tech on piston popup.
12.
Piston must be flat top (no domes or dishes), and may be manufactured by briggs or
aftermarket. No tech on piston
13.
pin, pin height, or rings.
14.
Coil must be OEM Briggs.
15.
Spark Plug is a non-tech item.
16.
Crankshaft: Must be briggs style cast crankshaft, no polishing or lightening.
17.
Maximum Stroke: 2.457″
18.
Crankshaft Bearings are non-tech items
19.
Connecting rod may be billet or stock cast.
20.
No tech on rod length.
21.
Camshaft Lift Max “as-raced” (with lash): .240″
22.
Lifters may be stock, or stock style billet. Clearancing is allowed in lifter galley.
23.
Carb may be stock oem flathead 5hp carb with dual briggs oem style pickup tubes and
removable jet.
24.
Maximum Carb Bore: .725″, no sleeving,
25.
OR may be Tillotson with .625″ max bore, auxiliary fuel pump and intake manifold legal
with Tilloton carb.
26.
No welding inside ports. No changing port face angles; port face must be stock.
27.
Any single wound, non-titanium valve spring; keepers and retainers are non-tech items.
28.
Valves must be stock materials, no titanium.
29.
Intake port Max size: .900″
30.
Intake Seat Max ID: 1.010″
31.
Intake Valve Head Minimum OD: 1.110″
32.
Intake Valve Stem Minimum OD: .245″
33.
Exhaust port Max size:1.010″
34.
Exhaust Seat Max ID: .885″
35.
Exhaust Valve Head Minimum OD: .985″
36.
Exhaust Valve Stem Minimum OD: .245″
37.
A Header is required. The header pipe must be braced, and must be located within the
confines of the kart. The use of a heat wrap or sleeve is mandatory and must cover the
majority of the header; wrap/sleeve may cover muffler, but muffler must be removable.
Ceramic Header coatings are legal.
38.
An RLV B91XL or B91MO muffler is required. Muffler is to be attached to header in a
safe manner with a clamp. Muffler may not be welded to header and must be removable.
Muffler must still be attached to the header when teched.
39.
Welding is permitted to the block for repairs and may not be done in such a way as to
provide a performance enhancing alteration.
40.
Bolts, screws, washers, etc. are non-tech items.
41.
ALL engine parts not mentioned are non-tech items except that they must be Briggs 5 HP
parts with exception of flywheel screen guard.
9.3.3 MODIFIED STOCK (Animal)
1.
Fuel- Methanol; must pass hydrometer test.
2.
Thread repair inserts are legal unless noted otherwise.
3.
Gaskets are non-tech items.
4.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
5.
Base engine may be Animal, Gas Animal, or LO206 as long as it meets specifications
listed.
6.
Engine block- no addition or subtractions of metal or any substance to the inside or outside
of the cylinder block unless noted. Angle milling or peak decking IS allowed.
7.
Side Cover (PTO side) must be factory stock casting. Connections may be added for
venting, or to pulse the fuel pump.
8.
Block may be welded for repairs and strengthening only. No performance-enhancing
weldments allowed.
9.
Block coil posts are non-tech.
10.
Ignition Kill Switch and Low Level Oil Sensor/Switch are optional. If removed, hole must
be plugged.
11.
Oil breather must vent to a catch container. An oil overflow catch system is mandatory.
Overflow tube must run from the crankcase breather to a catch container.
12.
Carburetor Overflow- If the carb utilized is fitted with an overflow it must be vented to an
oil catch container. The catch-container must be vented to atmosphere.
13.
An auxiliary fuel pump may be used.
14.
All sheet metal- Cooling Shrouds, Covers and Blower Housings must be installed but are
otherwise non-tech items
15.
Factory bolts, studs only. May be drilled and safety wired.
16.
Carburetor may be type as supplied on Animal/LO206 from factory, OR may be Tillotson
with .625″ max bore, auxiliary fuel pump and intake manifold legal with Tillotson carb.
17.
Animal Carburetor specifications: Venturi Measurement: Vertical: .795″ maximum.
18.
Horizontal: .615″ maximum at widest part
19.
Horizontal: .605″ maximum at narrowest part.
20.
Throttle bore .875″ maximum diameter
21.
Intake Port Maximum diameter .920″
22.
Exhaust Port maximum .980″
23.
Valve Cover must be factory stock. A pulsing connection is allowed.
24.
Cylinder Head Ports and Port Faces- must be factory stock; no modifications allowed.
25.
Cylinder Head Gasket Surface may be machined to any depth.
26.
Cylinder Head Combustion Chamber must be stock. No modifications allowed.
27.
Cylinder Head Welding is allowed only to repair rocker stud damage.
28.
Cylinder Head Gasket is a non-tech item.
Intake valve

valve stem minimum diameter .245″

valve head minimum diameter 1.055″

valve seat maximum inside diameter .975″
Exhaust valve

valve stem diameter .245″

valve head minimum diameter.935″

valve seat maximum inside diameter .850″
29.
No tech on Valve Face Angles.
30.
Valve Seat Angles are non-tech.
31.
Each valve must weight a minimum of 28 grams.
32.
Valve Heads must both be located above combustion chamber floor (no sinking).
33.
Valve Spring Seats may be machined.
34.
Valve Spring Shims are allowed, and are non-tech items.
35.
Pushrods are non-tech items.
36.
Valve Springs- any single wound, non-titanium valve spring is allowed.
37.
Valve Spring Retainers and Keepers are non-tech items.
38.
Rocker arms must be B&S part #691230 (US) or #797443 (metric). Rocker Arms may be
any ratio, but must tech within cam rules. Welding is permitted to strengthen rocker arms.
39.
Rocker studs must be stock, unaltered stock B&S part #694544 (US) or #797441 (metric)
and in stock location.
40.
Rocker Ball and Rocker arm stud plates are non-tech items.
41.
Push rods are non-tech items
42.
No tech on Piston pop up.
43.
Cylinder bore 2.725″ maximum
44.
Crankshaft stroke 2.205” maximum
45.
Maximum Intake and Exhaust is .255″. Valve Lift is checked from the top of the valve
spring retainer “as-raced” (with lash).
46.
Any unaltered SAE approved Flywheel is permitted. A coil bracket is permitted to alter
coil location.
47.
Ignition System- any non-battery fired ignition system is permitted
48.
Crankcase and cover must be B&S stock, and may have vents installed.
49.
Clutch- any dry disc or shoe type clutch is permitted.
50.
The use of a Chain Guard is mandatory.
51.
The factory pull rope starter is legal. An optional electric starter nut is allowed. A flywheel
screen/guard shall be required in place of the pull starter to prevent contact with the
flywheel if the electric starter nut is utilized and the original starter is removed, for safety
reasons.
52.
Exhaust Header is non-tech, but must be installed in a safe manner within the confines of
the kart, with the muffler installed.
53.
A Header support brace is mandatory. Heli-coiling of the exhaust is allowed.
54.
At least one bolt or nut must be safety wired on the cylinder head and exhaust header.
55.
Muffler must be an unaltered RLV B91XL (part number 4104) with round baffle holes
only. Safety wiring of the silencer to header is recommended.
56.
It is recommended for safety to wrap the exhaust header and muffler with a heat-protective
sleeve or wrap.
57.
Any single fuel pump allowed. May be pulsed from the block, side cover, or valve cover.
58.
Crankshaft Bearings- Aftermarket steel bearings allowed. No ceramic or self-aligning
bearings allowed.
59.
Crankshaft Gear must be factory stock, and may be welded to the crankshaft.
60.
Connecting Rod may be any length billet aluminum rod with babbit inserts.
61.
Piston- must remain factory stock.
62.
Piston Rings must be of stock quantity and configuration. Rings may be trued. Stock style
low tension rings may be used.
63.
Piston Pin is a non-tech item.
64.
Valve Lifters must be stock with round, flat base; no rollers.
65.
Camshaft must be stock core, but may be welded and heat treated.
66.
Camshaft (Non-Restricted classes)- Measured at the retainer “as-raced” (with lash) .255″
maximum lift, 240 degrees @ .050″, 115 degrees duration @ 200″
67.
Floor mounted fuel tank only
9.4 Adult Predator “Claimer” classes

Predator, 375lbs

Predator Ladies- (this is a "females only" class)- Per USKRA, LLC Predator class rules,
330lbs
A. The spirit and intent of these rules is to provide a true budget class with an engine total
value of $150 or less. Any attempt to circumvent these rules by adding a performance
enhancing product, either mechanical or fuel, shall be considered as an intentionally illegal
act and will result in disqualification for that race day.
B. Those who choose to race in this class enter with the knowledge and acceptance of the fact
that this is a "Claimer" class. If your engine is claimed by another competitor, you must
remove your engine and give it to the Tech Man, minus any non-claim parts; no arguments
and no foul language or threats to anyone. If you cannot or will not abide by these rules, do
not enter a kart in this class. Failure to surrender an engine when claimed will result in a
loss of the current season's points up to and including the date of the claim.
Rules
1.
2.
3.
4.
5.
ANY Predator 6.5hp 212cc base engine, whether conventional or hemi chambered head.
Fuel is 87 octane gasoline.
Cylinder heads may NOT be interchanged between hemi and non-hemi models.
Engine must utilize the stock air filter.
The Low Oil Sensor switch may be electrically disconnected, but the switch must remain
installed.
6. The governor assembly may be removed in its entirety, and if removed the block hole must
be plugged.
7. The only approved legal exhaust is a .750" O.D. mini pipe and RLV mini muffler.
8. Exhaust system must be located within the confines of the kart.
9. It is recommended that the exhaust system be wrapped or sleeved with a heat-resistant
fabric to reduce the risk of burns.
10. Engine Fuel Tank may be located in the stock position or optionally a floor mounted fuel
tank may be utilized. If a top mounted fuel tank is utilized, the cap must be taped down. If
a floor mounted fuel tank is used, an auxiliary fuel pump and top plate with associated fuel
and pulse lines are allowed, and the fuel pump may be pulsed from the engine sidecover
crankcase, or valve cover.
11. The stock flywheel may not be lightened or altered in any way; it must remain factory
OEM stock. Timing key must be stock, unaltered.
12. A flywheel must be replaced if damaged, however the engine must always utilize a stock
flywheel of the same style and manufacture of that which was original equipment for that
engine, with a stock timing key.
13. All items other than the ones specifically mentioned are to be stock OEM parts in OEM
locations.
14. Any size shoe-type dry clutch allowed.
15. This is an "Open" tire class. Any tire used for kart racing allowed. No yard kart turf tires.
16. The Tech Man may choose to do a tear-down of an engine to ensure legality after the days
races are finished for that kart. Engine owner must surrender his engine for tech. Tech is
performed to insure no illegal parts are in or on the engine.
Claiming an engine
17. Claim Fee is $150
18. Essentially, the "claim" made on an engine contains only the parts which were on the
engine when it was originally purchased, with the exception of the removed governor.
19. Anyone actively participating in the current race may claim an engine, regardless of the
position the racer starts or finishes in. Racer must at least start the race in which the claimed
engine is racing, even if they receive a DNF score.
20. In the event of a claim on an engine with a floor mounted fuel tank, the floor tank, auxiliary
fuel pump and top plate are not included in the claim.
21. Exhaust system (header pipe and muffler) are not part of any claim made, and shall remain
the property of the engine owner.
22. Motor mount, clutch, chain guard, and aftermarket throttle linkage are considered
non-engine add-on's, and are not part of the claim.
04/09/2014 UPDATE! EFFECTIVE IMMEDIATELY



ARC #6625 and #6626 billet flywheels are allowed as an option until the end of 2014.
On 01-01-2015 the use of a billet flywheel shall be mandatory.
The claimer price will also be increased to $275 (on engines utilizing a billet flywheel
only).
Flywheel key, ignition timing, and spark plug are non-tech items.
9.5 Limited Open Classes
9.5.0.1 The USKRA, LLC Limited Open classes are open to the following engines:
Honda, Clone, Briggs Flathead, Briggs Animal.
9.5.0.2 Class Weights, Kart + Driver:
 Jr. Limited Open 280lbs (NOTE Age requirement: 12-15 yrs)
 Light 330lbs
 Medium 360lbs
 Heavy 390lbs
 Super Heavy 420lbs
 Sumo 450lbs
The rules are broken down for each type of engine as follows:
9.5.1 USKRA, LLC Junior Limited Open Rules
 Jr. Limited Open 280lbs (Age requirement: 12-15 yrs)
 Engine utilized may be any engine manufacture and carburetor type as listed in Section
9.5.2, 9.5.3, or 9.5.4, however the engine must utilize a maximum 0.625” venturi
carburetor.
9.5.2 USKRA, LLC Limited Open Rules (Clone, Honda GX200)
1. Engine Type- May be 6.5HP OHV Clone or Original Honda GX200. All parts may be
6.5HP OHV Clone or Original Honda GX200. Alterations are allowed as noted.
2. Fuel type- Methanol. Must pass hydrometer test.
3. Gasket Sealer is allowed.
4. Gaskets are Non-Tech items
5. All bolts may be replaced with studs if desired. Bolts and studs are non-tech items. Must be
in original locations and configuration.
6. Welding is permitted to the block only for repairs and strengthening. Welding may not be
done in such a manner as to produce a performance enhancing modification.
7. Kill switch and Low Oil sensor are optional; if removed, holes must be plugged.
8. Cylinder Bore 2.725" maximum.
9. Block Girdle is legal
10. Cylinder Block deck may be machined.
11. O-ringing the block deck is not legal.
12. Ignition Coil must be factory unit (Non-tech item; no MSD boxes). The PVL coil is
allowed. A mounting bracket is allowed to properly position the coil.
13. Flywheel- Billet aluminum or billet steel only. Must be approved by SFI.
14. Timing keys are non-tech items
15. Factory flywheel shroud mandatory.
16. Flywheel Electric Starter Nut is legal. If an electric starter is utilized, a flywheel screen is
mandatory.
17. The flywheel must be covered so as to keep body parts and clothing from contacting, or
becoming entangled in the flywheel.
18. 3rd Bearing Support legal
19. Exhaust Header- Multi-stage legal, any length within the confines of the kart.
20. Muffler type- RLV B91-MO or RLV 4104 legal. (Screen Hole sizes may not be altered).
21. Cylinder Head must start with a 6.5HP OHV Clone Cylinder Head, or Predator (60363
Base engine part) Hemi head. It is legal to to open the dowel holes to for fit the hemi head
onto the 6.5hp clone (non-Predator) block. The Predator "Hemi" is actually a 7hp block,
with more bore and stroke, and is NOT legal for use.
22. Welding is allowed on the cylinder head for repair purposes only. No welding allowed in
the combustion chamber, and ports may not be altered by welding in such a way as to
create a performance enhancement.
23. Cylinder Head Combustion Chamber- No Tech other than no welding allowed.
24. Machining of the Cylinder Head Gasket Surface is legal, and Non-Tech.
25. Modifications may not be made to the port faces. No changing of the port entry/exit angles.
26. Valve Cover is a Non-Tech item.
27. Valve Springs, retainers, and keepers are non-tech, except no titanium.
28. Valve Spring Shims are legal, non-tech items.
29. Any Rocker Arm ratio (No Tech). Rockers must be stamped steel (no billet). Champion old
style and new style rockers are also legal.
30. Rocker Studs must be of stock configuration
31. Valves may be carbon or stainless steel, no titanium.
32. Valve Face Angles are Non-Tech.
33. No tech on valve weights.
34. Valve Stem diameters .218" maximum, .214" minimum
35. Valve Seat angles are Non-Tech.
36. Intake Valve Seat Maximum Inside Dimension is .910"
37. Exhaust Valve Seat Maximum Inside Dimension is .880"
38. Intake Valve Head Outside Diameter .975" minimum, .990" maximum
39. Exhaust Valve Head Outside Diameter .935" minimum, .950" maximum
40. Valve Seats (Bottom) May be blended into the port.
41. No tech on Pushrod Guide Plate (Bushing type legal)
42. Aftermarket Pushrods are allowed. Pushrods are Non-Tech items.
43. Sidecover may be stock cast unit or billet, and may be vented.
44. Factory crankshaft only (Clone or Original Honda; no billet). Stroke 2.110" minimum,
2.135" maximum, minor grinding allowed to clearance for camshaft lobes, but no polishing
or knife-edging of counterweights/throws.
45. Crankshaft Connecting Rod Journal- 1.185" maximum, 1.165" minimum.
46. Crankshaft Bearings- Aftermarket steel bearings legal, but no self-aligning type or
ceramic.
47. Crankshaft Timing Gear is a Non-Tech item and may be welded to the crankshaft
48. Connecting Rods must be billet aluminum only. No cast aluminum, steel, or titanium rods
allowed. Any length.
49. No overhead camshaft engines allowed. Camshaft is a Non-Tech item except no rollers.
50. Lifters must be stock appearing and of original configuration (flat tappets, no rollers)
51. Piston- No tech. No tech on pop-up. Piston may be flat, dished, or domed.
52. Piston Rings- No tech
53. Engine must be normally aspirated- No Turbochargers, Superchargers, or Nitrous.
54. Carburetor- Any Honda or Clone Carb allowed, or Tillotson Max venturi bore 0.900"
55. Throttle Shaft. Butterfly and Throttle Shaft must be removable. No slide carbs.
56. Intake Manifold is a Non-Tech item, except that it may not be of such a design as to
produce an air ram, and must be within the confines of the kart.
57. Fuel pump may be pulsed from block, intake, valve cover, or side cover.(1) One pulse
style, single or dual outlet fuel pump may be used.
58. Floor mounted fuel tank only
59. Dry disc or shoe clutches only
9.5.3 USKRA, LLC Limited Open (Briggs Flathead)
1. Flywheel enclosing sheet metal (2 pcs) must be installed.
2. Gaskets are non-tech items.
3. Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
4. A billet flywheel is mandatory.
5. A flywheel bracket may be utilized to lower the coil when using a 3HP flywheel.
6. In lieu of a pull starter, the flywheel may utilize an electric starter nut for use with an
electric starter (hand held).
7. A flywheel washer is required in all cases.
8. Flywheel key non-tech item, and does not have to be installed.
9. Block coil posts are non-tech.
10. Cylinder Head must be briggs.
11. Block must be original Briggs flathead 5hp.
12. Welding is open.
13. Clearancing is allowed in lifter galley.
14. Porting is non-tech.
15. Valve chamber may be back faced to secure upper valve spring retainers.
16. Maximum Bore: 2.6500"
17. Angle milling of the block deck is permitted.
18. No tech on piston popup.
19. Piston top may be flat, domed or dished, and may be manufactured by briggs or
aftermarket.
20. No tech on piston pin, pin height, or rings.
21. Coil must be non-battery fired.
22. Spark Plug is a non-tech item.
23. Crankshaft: Billet or Cast are legal, polishing and/or lightening is permitted.
24. Maximum Stroke: 2.537"
25. Crankshaft Bearings are non-tech items
26. Billet sidecover is legal
27. Connecting rod must be billet aluminum.
28. No tech on rod length.
29. Camshaft: No Tech
30. Lifters may be stock, or stock style billet.
31. Any single Carb; type is open.
32. Carb Venturi .900" max.
33. An auxiliary fuel pump and intake manifold is legal.
34. Filter and filter adapter are non-tech
35. Intake manifold must be removable.
36. No changing port face angles; port face must be stock.
37. Any single or dual non-titanium valve spring is legal
38. Valve Spring keepers and retainers are non-tech items.
39. Valves must be stock materials, no titanium.
40. Intake port Max size: no tech
41. Intake Seat Max ID: 1.010"
42. Intake Valve Head Minimum OD: 1.110"
43. Intake Valve Stem Minimum OD: .245"
44. Exhaust port Max size: no tech"
45. Exhaust Seat Max ID: .885"
46. Exhaust Valve Head Minimum OD: .985"
47. Exhaust Valve Stem Minimum OD: .245"
48. A Header is required. The header pipe must be braced, and must be located within the
confines of the kart.
49. The use of a header heat wrap or sleeve is mandatory and must cover the majority of the
header; wrap/sleeve may cover muffler, but muffler must be removable. Ceramic Header
coatings are legal.
50. An RLV B91XL or B91MO muffler is required. Muffler is to be attached to header in a
safe manner with a clamp. Muffler may not be welded to header and must be removable.
Muffler must still be attached to the header when teched.
51. When tracks optionally allow engines to be raced with an "Open" header (no muffler), a
slide-on/clamp-on washer is required for safety.
52. Bolts, screws, washers, etc. are non-tech items.
9.5.4 USKRA, LLC Limited Open (Briggs Animal)
1.
2.
3.
4.
Fuel- Methanol; must pass hydrometer test.
Thread repair inserts are legal unless noted otherwise.
Gaskets are non-tech items.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
5. Base engine may be Animal, Gas Animal, or LO206 as long as it meets specifications
listed.
6. Engine block- no addition or subtractions of metal or any substance to the
7. inside or outside of the cylinder block unless noted. Angle milling or peak decking IS
allowed.
8. O-ringing the block deck is not legal.
9. Side Cover (PTO side) may be factory stock casting or billet. Connections may be added
for venting, or to pulse the fuel pump.
10. Block may be welded for repairs and strengthening only. No performance-enhancing
weldments allowed.
11. Block coil posts are non-tech.
12. Ignition Kill Switch and Low Level Oil Sensor/Switch are optional. If removed, hole must
be plugged.
13. Oil breather must vent to a catch container. An oil overflow catch system is mandatory.
Overflow tube must run from the crankcase breather to a catch container.
14. Carburetor Overflow- If the carb utilized is fitted with an overflow it must be vented to an
oil catch container. The catch-container must be vented to atmosphere.
15. An auxiliary fuel pump may be used.
16. All sheet metal- Cooling Shrouds, Covers and Blower Housings must be installed but are
otherwise non-tech items
17. Factory bolts, studs only. May be drilled and safety wired.
18. Carburetor may be type as supplied on Animal/LO206 from factory, OR may be Tillotson
with .900" max venturi bore, auxiliary fuel pump and intake manifold legal with Tillotson
carb.
19. Animal Carburetor specifications: Venturi Measurement: Vertical: .795" maximum.
20. Horizontal: .615" maximum at widest part
21. Horizontal: .605" maximum at narrowest part.
22. Throttle bore .875" maximum diameter
23. Intake Port Maximum diameter .920"
24. Exhaust Port maximum .980"
25. Valve Cover must be factory stock. A pulsing connection is allowed.
26. Cylinder Head Ports and Port Faces- must be factory stock; no modifications allowed.
27. Cylinder Head Gasket Surface may be machined to any depth.
28. Cylinder Head Combustion Chamber must be stock. No modifications allowed.
29. Cylinder Head Welding is allowed only to repair rocker stud damage.
30. Cylinder Head Gasket is a non-tech item.
31. Intake valve stem minimum diameter .245"
32. Intake valve head minimum diameter 1.055"
33. Intake valve seat maximum inside diameter .975"
34. Exhaust valve stem diameter .245"
35. Exhaust valve head minimum diameter.935"
36. Exhaust valve seat maximum inside diameter .850"
37. No tech on Valve Face Angles.
38. Valve Seat Angles are non-tech.
39. Each valve must weight a minimum of 28 grams.
40. Valve Heads must both be located above combustion chamber floor (no sinking).
41. Valve Spring Seats may be machined.
42. Valve Spring Shims are allowed, and are non-tech items.
43. Pushrods are non-tech items.
44. Valve Springs- any single wound, non-titanium valve spring is allowed.
45. Valve Spring Retainers and Keepers are non-tech items, except no titanium allowed.
46. Rocker arms must be B&S part #691230 (US) or #797443 (metric). Rocker Arms may be
any ratio, but must tech within cam rules.
47. Welding is permitted to strengthen rocker arms.
48. Rocker studs must be stock, unaltered stock B&S part #694544 (US) or #797441 (metric)
and in stock location.
49. Rocker Ball and Rocker arm stud plates are non-tech items.
50. Push rods are non-tech items
51. No tech on Piston pop up.
52. Cylinder bore 2.730" maximum
53. Crankshaft stroke 2.205” maximum
54. Maximum Intake and Exhaust is .310". Valve Lift is checked from the top of the valve
spring retainer "as-raced" (with lash).
55. Any unaltered SAE approved Flywheel is permitted. A coil bracket is permitted to alter
coil location.
56. Ignition System- any non-battery fired ignition system is permitted
57. Crankcase and cover must be B&S stock, and may have vents installed.
58. Clutch- any dry disc or shoe type clutch is permitted.
59. The use of a Chain Guard is mandatory.
60. The factory pull rope starter is legal. An optional electric starter nut is allowed. A flywheel
screen/guard shall be required in place of the pull starter to prevent contact with the
flywheel if the electric starter nut is utilized and the original starter is removed, for safety
reasons.
61. Exhaust Header is non-tech, but must be installed in a safe manner within the confines of
the kart, with the muffler installed.
62. A Header support brace is mandatory. Heli-coiling of the exhaust is allowed.
63. At least one bolt or nut must be safety wired on the cylinder head and exhaust header.
64. Muffler must be an unaltered RLV B91XL (part number 4104) with round baffle holes
only. Safety wiring of the silencer to header is recommended.
65. When tracks optionally allow engines to be raced with an "Open" header (no muffler), a
slide-on/clamp-on washer is required for safety.
66. It is recommended for safety to wrap the exhaust header and muffler with a heat-protective
sleeve or wrap.
67. Any single fuel pump allowed. May be pulsed from the block, side cover, or valve cover.
68. Crankshaft Bearings- Aftermarket steel bearings allowed. No ceramic or self-aligning
bearings allowed.
69. Crankshaft Gear must be factory stock, and may be welded to the crankshaft.
70. Connecting Rod may be any length billet aluminum rod with babbit inserts.
71. Piston- must be flat top or dished; no domed pistons.
72. Piston Rings are non-tech items
73. Piston Pin is a non-tech item.
74. Valve Lifters must be stock with round, flat base; no rollers.
75. Floor mounted fuel tank only
9.6 USKRA, LLC Stock Appearing
9.6.0.1 The USKRA, LLC Stock Appearing classes are open to the following engines:
Honda, Clone, Briggs Flathead, Briggs Animal.
NOTE! The only difference in design specifications between “Stock Appearing” and “Limited
Open” is the induction system (carburetor/manifold); this makes it simple to alternate between
these classes as desired.
9.6.0.2 Class Weights, Kart + Driver:

Light 330lbs

Medium 360lbs

Heavy 390lbs

Super Heavy 420lbs

Sumo 450lbs
The rules are broken down for each type of engine below.
9.6.1 USKRA, LLC Stock Appearing Rules (Clone, Honda GX200)
1.
Engine Type- May be 6.5HP OHV Clone or Original Honda GX200. All parts may be
6.5HP OHV Clone or Original Honda GX200.
2.
Alterations are allowed as noted.
3.
Fuel type- Methanol. Must pass hydrometer test.
4.
Gasket Sealer is allowed.
5.
Gaskets are Non-Tech items
6.
All bolts may be replaced with studs if desired. Bolts and studs are non-tech items. Must be
in original locations and configuration.
7.
Welding is permitted to the block only for repairs and strengthening. Welding may not be
done in such a manner as to produce a performance enhancing modification.
8.
Kill switch and Low Oil sensor are optional; if removed, holes must be plugged.
9.
Cylinder Bore 2.725″ maximum.
10.
Block Girdle is legal
11.
Cylinder Block deck may be machined.
12.
O-ringing the block deck is not legal.
13.
Ignition Coil must be factory unit (Non-tech item; no MSD boxes). The PVL coil is
allowed. A mounting bracket is allowed to properly position the coil.
14.
Flywheel- Billet aluminum or billet steel only. Must be approved by SFI.
15.
Timing keys are non-tech items
16.
Factory flywheel shroud mandatory.
17.
Flywheel Electric Starter Nut is legal. If an electric starter is utilized, a flywheel screen is
mandatory.
18.
The flywheel must be covered so as to keep body parts and clothing from contacting, or
becoming entangled in the flywheel.
19.
3rd Bearing Support legal
20.
Exhaust Header- Multi-stage legal, any length within the confines of the kart.
21.
Muffler type- RLV B91-MO or RLV 4104 legal. (Screen Hole sizes may not be altered).
22.
Cylinder Head must start with a 6.5HP OHV Clone Cylinder Head, or Predator (60363
Base engine part) Hemi head. It is legal to to open the dowel holes to for fit the hemi head
onto the 6.5hp clone (non-Predator) block. The Predator “Hemi” is actually a 7hp block,
with more bore and stroke, and is NOT legal for use.
23.
Welding is allowed on the cylinder head for repair purposes only. No welding allowed in
the combustion chamber, and ports may not be altered by welding in such a way as to
create a performance enhancement.
24.
Cylinder Head Combustion Chamber- No Tech other than no welding allowed.
25.
Machining of the Cylinder Head Gasket Surface is legal, and Non-Tech.
26.
Modifications may not be made to the port faces. No changing of the port entry/exit angles.
27.
Valve Cover is a Non-Tech item.
28.
Valve Springs, retainers, and keepers are non-tech, except no titanium.
29.
Valve Spring Shims are legal, non-tech items.
30.
Any Rocker Arm ratio (No Tech). Rockers must be stamped steel (no billet). Champion old
style and new style rockers are also legal.
31.
Rocker Studs must be of stock configuration
32.
Valves may be carbon or stainless steel, no titanium.
33.
Valve Face Angles are Non-Tech.
34.
No tech on valve weights.
35.
Valve Stem diameters .218″ maximum, .214″ minimum
36.
Valve Seat angles are Non-Tech.
37.
Intake Valve Seat Maximum Inside Dimension is .910″
38.
Exhaust Valve Seat Maximum Inside Dimension is .880″
39.
Intake Valve Head Outside Diameter .975″ minimum, .990″ maximum
40.
Exhaust Valve Head Outside Diameter .935″ minimum, .950″ maximum
41.
Valve Seats (Bottom) May be blended into the port.
42.
No tech on Pushrod Guide Plate (Bushing type legal)
43.
Aftermarket Pushrods are allowed. Pushrods are Non-Tech items.
44.
Sidecover may be stock cast unit or billet, and may be vented.
45.
Factory crankshaft only (Clone or Original Honda; no billet). Stroke 2.110″ minimum,
2.135″ maximum, minor grinding allowed to clearance for camshaft lobes, but no
polishing or knife-edging of counterweights/throws.
46.
Crankshaft Connecting Rod Journal- 1.185″ maximum, 1.165″ minimum.
47.
Crankshaft Bearings- Aftermarket steel bearings legal, but no self-aligning type or
ceramic.
48.
Crankshaft Timing Gear is a Non-Tech item and may be welded to the crankshaft
49.
Connecting Rods must be billet aluminum only. No cast aluminum, steel, or titanium rods
allowed. Any length.
50.
No overhead camshaft engines allowed. Camshaft is a Non-Tech item except no rollers.
51.
Lifters must be stock appearing and of original configuration (flat tappets, no rollers)
52.
Piston- No tech. No tech on pop-up. Piston may be flat, dished, or domed.
53.
Piston Rings- No tech
54.
Engine must be normally aspirated- No Turbochargers, Superchargers, or Nitrous.
55.
Carburetor- Any Honda or Clone Carb allowed.
56.
All carb parts may be 6.5HP OHV Clone or Original Honda GX200.
57.
No Tech on bore size or appearance. Epoxy may be added to inside or outside of carburetor
bore.
58.
No Tech on Carburetor Throttle Shaft. Butterfly and Throttle Shaft must be removable. No
slide carbs.
59.
Intake Manifold (or phenolic spacer) is a Non-Tech item, billet allowed.
60.
Fuel pump may be pulsed from block, intake, valve cover, or side cover.(1) One pulse
style, single or dual outlet fuel pump
61.
may be used.
62.
Floor mounted fuel tank only
63.
Dry disc or shoe clutches only
9.6.2 USKRA, LLC Stock Appearing (Briggs Flathead)
1.
Flywheel enclosing sheet metal (2 pcs) must be installed.
2.
Gaskets are non-tech items.
3.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
4.
A billet flywheel is mandatory.
5.
A flywheel bracket may be utilized to lower the coil when using a 3HP flywheel.
6.
In lieu of a pull starter, the flywheel may utilize an electric starter nut for use with an
electric starter (hand held).
7.
A flywheel washer is required in all cases.
8.
Flywheel key non-tech item, and does not have to be installed.
9.
Block coil posts are non-tech.
10.
Cylinder Head must be briggs.
11.
Block must be original Briggs flathead 5hp.
12.
Welding is open.
13.
Clearancing is allowed in lifter galley.
14.
Porting is non-tech.
15.
Valve chamber may be back faced to secure upper valve spring retainers.
16.
Maximum Bore: 2.6500″
17.
Angle milling of the block deck is permitted.
18.
No tech on piston popup.
19.
Piston top may be flat, domed or dished, and may be manufactured by briggs or
aftermarket.
20.
No tech on piston pin, pin height, or rings.
21.
Coil must be non-battery fired.
22.
Spark Plug is a non-tech item.
23.
Crankshaft: Billet or Cast are legal, polishing and/or lightening is permitted.
24.
Maximum Stroke: 2.537″
25.
Crankshaft Bearings are non-tech items
26.
Billet sidecover is legal, and venting Sidecover is legal.
27.
Connecting rod must be billet aluminum.
28.
No tech on rod length.
29.
Camshaft: No Tech
30.
Lifters may be stock, or stock style billet.
31.
Any stock appearing briggs 5hp flathead style carb is legal. Epoxy may be added to inside
or outside of carburetor bore.
32.
Filter and filter adapter are non-tech
33.
No changing port face angles; port face must be stock.
34.
Any single or dual non-titanium valve spring is legal
35.
Valve Spring keepers and retainers are non-tech items.
36.
Valves must be stock materials, no titanium.
37.
Intake port Max size: no tech
38.
Intake Seat Max ID: 1.010″
39.
Intake Valve Head Minimum OD: 1.110″
40.
Intake Valve Stem Minimum OD: .245″
41.
Exhaust port Max size: no tech”
42.
Exhaust Seat Max ID: .885″
43.
Exhaust Valve Head Minimum OD: .985″
44.
Exhaust Valve Stem Minimum OD: .245″
45.
A Header is required. The header pipe must be braced, and must be located within the
confines of the kart.
46.
The use of a header heat wrap or sleeve is mandatory and must cover the majority of the
header; wrap/sleeve may cover muffler, but muffler must be removable. Ceramic Header
coatings are legal.
47.
An RLV B91XL or B91MO muffler is required. Muffler is to be attached to header in a
safe manner with a clamp. Muffler may not be welded to header and must be removable.
Muffler must still be attached to the header when teched.
48.
When tracks optionally allow engines to be raced with an “Open” header (no muffler), a
slide-on/clamp-on washer is required for safety.
49.
Bolts, screws, washers, etc. are non-tech items.
9.6.3 USKRA, LLC Stock Appearing (Briggs Animal)
1.
Fuel- Methanol; must pass hydrometer test.
2.
Thread repair inserts are legal unless noted otherwise.
3.
Gaskets are non-tech items.
4.
Any sealants and Thread Lockers are allowed so long as any part which must be removed
for technical inspection can be removed.
5.
Base engine may be Animal, Gas Animal, or LO206 as long as it meets specifications
listed.
6.
Engine block- no addition or subtractions of metal or any substance to the
7.
inside or outside of the cylinder block unless noted. Angle milling or peak
decking ISallowed.
8.
O-ringing the block deck is not legal.
9.
Side Cover (PTO side) may be factory stock casting or billet. Connections may be added
for venting, or to pulse the fuel pump.
10.
Block may be welded for repairs and strengthening only. No performance-enhancing
weldments allowed.
11.
Block coil posts are non-tech.
12.
Ignition Kill Switch and Low Level Oil Sensor/Switch are optional. If removed, hole must
be plugged.
13.
Oil breather must vent to a catch container. An oil overflow catch system is mandatory.
Overflow tube must run from the crankcase breather to a catch container.
14.
Carburetor Overflow- If the carb utilized is fitted with an overflow it must be vented to an
oil catch container. The catch-container must be vented to atmosphere.
15.
An auxiliary fuel pump may be used.
16.
All sheet metal- Cooling Shrouds, Covers and Blower Housings must be installed but are
otherwise non-tech items
17.
Factory bolts, studs only. May be drilled and safety wired.
18.
Carburetor must be type as supplied on Animal/LO206 from factory, but may be modified
internally as desired.
19.
Epoxy may NOT be added to inside or outside of carburetor bore.
20.
Intake Port Maximum diameter .920″
21.
Exhaust Port maximum .980″
22.
Valve Cover must be factory stock. A pulsing connection is allowed.
23.
Cylinder Head Ports and Port Faces- must be factory stock; no modifications allowed.
24.
Cylinder Head Gasket Surface may be machined to any depth.
25.
Cylinder Head Combustion Chamber must be stock. No modifications allowed.
26.
Cylinder Head Welding is allowed only to repair rocker stud damage.
27.
Cylinder Head Gasket is a non-tech item.
Intake valve
28.
valve stem minimum diameter .245″
29.
valve head minimum diameter 1.055″
30.
valve seat maximum inside diameter .975″
Exhaust valve
31.
valve stem diameter .245″
32.
valve head minimum diameter.935″
33.
valve seat maximum inside diameter .850″
34.
No tech on Valve Face Angles.
35.
Valve Seat Angles are non-tech.
36.
Each valve must weight a minimum of 28 grams.
37.
Valve Heads must both be located above combustion chamber floor (no sinking).
38.
Valve Spring Seats may be machined.
39.
Valve Spring Shims are allowed, and are non-tech items.
40.
Pushrods are non-tech items.
41.
Valve Springs- any single wound, non-titanium valve spring is allowed.
42.
Valve Spring Retainers and Keepers are non-tech items, except no titanium allowed.
43.
Rocker arms must be B&S part #691230 (US) or #797443 (metric). Rocker Arms may be
any ratio, but must tech within cam rules.
44.
Welding is permitted to strengthen rocker arms.
45.
Rocker studs must be stock, unaltered stock B&S part #694544 (US) or #797441 (metric)
and in stock location.
46.
Rocker Ball and Rocker arm stud plates are non-tech items.
47.
Push rods are non-tech items
48.
No tech on Piston pop up.
49.
Cylinder bore 2.730″ maximum
50.
Crankshaft stroke 2.205” maximum
51.
Maximum Intake and Exhaust is .310″. Valve Lift is checked from the top of the valve
spring retainer “as-raced” (with lash).
52.
Any unaltered SAE approved Flywheel is permitted. A coil bracket is permitted to alter
coil location.
53.
Ignition System- any non-battery fired ignition system is permitted
54.
Crankcase and cover must be B&S stock, and may have vents installed.
55.
Clutch- any dry disc or shoe type clutch is permitted.
56.
The use of a Chain Guard is mandatory.
57.
The factory pull rope starter is legal. An optional electric starter nut is allowed. A flywheel
screen/guard shall be required in place of the pull starter to prevent contact with the
flywheel if the electric starter nut is utilized and the original starter is removed, for safety
reasons.
58.
Exhaust Header is non-tech, but must be installed in a safe manner within the confines of
the kart, with the muffler installed.
59.
A Header support brace is mandatory. Heli-coiling of the exhaust is allowed.
60.
At least one bolt or nut must be safety wired on the cylinder head and exhaust header.
61.
Muffler must be an unaltered RLV B91XL (part number 4104) with round baffle holes
only. Safety wiring of the silencer to header is recommended.
62.
When tracks optionally allow engines to be raced with an “Open” header (no muffler), a
slide-on/clamp-on washer is required for safety.
63.
It is recommended for safety to wrap the exhaust header and muffler with a heat-protective
sleeve or wrap.
64.
Any single fuel pump allowed. May be pulsed from the block, side cover, or valve cover.
65.
Crankshaft Bearings- Aftermarket steel bearings allowed. No ceramic or self-aligning
bearings allowed.
66.
Crankshaft Gear must be factory stock, and may be welded to the crankshaft.
67.
Connecting Rod may be any length billet aluminum rod with babbit inserts.
68.
Piston- must be flat top or dished; no domed pistons.
69.
Piston Rings are non-tech items
70.
Piston Pin is a non-tech item.
71.
Valve Lifters must be stock with round, flat base; no rollers.
72.
Floor mounted fuel tank only
9.7 Open/RWYB
9.7.0 The Open/RWYB Class is open to the engine types listed below in Section 9.7.1. “Freight
Train” engines (dual engines) are permitted.
Calculating your minimum Kart + Driver weight requires some math. The formulas and variables
are given below, but for your convenience we've already set up a Microsoft Excel spreadsheet to
quickly perform the calculations from your input; simply download the file from the FILES
directory (tab) from within the USKRA, LLC Group on Facebook, open it in Excel (or the FREE
Open Office program), and enter your data in the light orange cells. The program will do all of the
math for you. Please note that although these rules are similar to those used by UAS, they are not
the same.
The actual formulas used are:

Number of engines or cylinders

cc= Bore (in) * Bore (in) * Stroke (in) * .7854 * 16.39

Induction var = +10lbs for every engine or cylinder that is turbocharged, supercharged, or
has nitrous oxide injected capabilities.

min wt = wt var + (cc var * Number of engines or cylinders) + Induction var
9.7.1 Engine Types and Variables






Wt var cc var
Flathead 4 Stroke (510cc or less)
260
cc/3
Overhead CAM 4 Stroke (Sgl or Dual OHC, 510cc or less) 225
cc/2.5
Overhead VALVE 4 Stroke (510cc or less)
190
cc/2.125
Rotary or Reed Valve 2 Stroke (255cc or less)
175
cc/1
Piston Port 2 Stroke (255cc or less)
203
cc/1.125
***Wankel (Sgl Rotor Rotary, 295cc max)
153
cc/1.0625
(***Wankel may not utilize a turbocharger, supercharger, or nitrous oxide)
9.8 LO206 Classes
Kid Karts
.350" Restrictor Junior LO206 #124332-8202 engine
LO206 Junior with locking cap Part #555726 installed on the carburetor slide cover.
Slide (#555728)
4,100 RPM Rev Limiter
Minimum Kart + Driver weight = 190lbs
Rookie LO206
LO206 with locking cap Part #555726 installed on the carburetor slide cover.
‘Purple’ slide (#555735) Max Slide Height .342"
Minimum Kart + Driver weight = 220lbs
Sportsman LO206
LO206 with locking cap Part #555726 installed on the carburetor slide cover.
‘Red’ Slide (#555733) Max slide Height .440"
Minimum Kart + Driver weight = 250lbs
Junior LO206
LO206 with locking cap Part #555726 installed on the carburetor slide cover.
‘Blue’ Slide (555734) Max Slide Height .520"
Minimum Kart + Driver weight = 280lbs
LO206 (Non-Restricted Classes will be offered in Ultra Light, Light, Medium, Heavy, Super
Heavy, and Sumo minimum kart + driver weights)
LO206 #124332-8201 engine
Stock Slide (#555590)
1. Engine must be sealed with the two custom, Homeland Security Tier III rated seals that are
installed at the factory. Seals can have either a black anodized or bare aluminum finish on
both main body ends. Tampering with the factory installed engine seals is not permitted
and is considered an intentional attempt to enhance performance.Both (2) B&S engine
seals must be present with both the fastener and seal in “as shipped” from the factory
location and condition. Any defined tampering with the fasteners or damage to the
wire/seal itself (example: delaminated hologram) are grounds for disqualification. Take
proper care of your seals to ensure their integrity. It is recommended that you wrap your
seals (using a plastic bag, etc.) to prevent exposure to harsh solvents such as carb cleaner,
etc. In the event the seals are tampered with, the engine will no longer be eligible for
competition. Should an engine require dismantling for any reason that requires breaking of
the seals, the engine owner must contact Briggs & Stratton.
2. Engines must have a serialized block, except early built engines without a block serial
number. The engine identification sticker must be in place and legible. If the sticker is
illegible or missing the engine must be tagged with a suitable sticker or seal approved by
the technical inspector.


3. Engine is to be unaltered "Factory Stock" with no alterations except as noted in these rules.
4. All parts must be unaltered Briggs & Stratton LO206 parts specifically made for this
engine by Briggs & Stratton.
5. All parts may be compared with a known stock part to determine legality.
6. No aftermarket parts to be used unless specified in these regulations.
7. The tech official, at their sole discretion, may at any time replace a competitor’s sealed
engine, carburetor, or head assembly with another sealed engine or known stock part.
Failure to comply is grounds for disqualification.
8. Air Filter must be Green Air Filter Part #555729. No modification to the filter element in
an effort to enhance performance is permitted. Filter adapters are not allowed, filter must
attach directly to carburetor air horn A protective shield may be attached but under no
circumstances is it allowed to create a ram-air effect.
9. Engine Fuel is to be no greater than 94 octane. The addition of fuel additives in any manner
is not permitted.
10. Oil breather and carburetor overflow must vent to a catch container. An oil overflow catch
system is mandatory. Overflow tube must run from the crankcase breather to a catch
container. The catch-container must be vented to atmosphere.
11. Any auxiliary fuel pump pulsed from a pulse fitting mounted on the oil fill fitting located
on the engine side cover only is legal.
12. Aftermarket one-piece filler/pulse fittings are permitted.
13. The use of a single fuel filter is legal, and is a non-tech item.
14. All pieces of the engine cooling shroud/blower housing and control panel must be stock
B&S as installed at the factory without any performance enhancing modifications. Taping
or covering of the rewind shroud is not permitted. Engine Shroud may be painted or
powder coated any color.
15. Any bolt, with the exception of the head bolts, that are used to secure sheet metal shrouds
and covers may be replaced with larger diameter bolts.
16. Helicoil thread inserts may be installed for shrouds, valve cover, oil drain, oil fill holes,
blower housing, and exhaust pipe attachment studs on the head and lower brackets. No
helicoiling of rocker arm mounting holes. Helicoiling of the exhaust is allowed.
17. Needle Jet C-clip must be properly installed but may be installed at any of the 5 factory
settings on the needle jet.
18. Carb slide height may be optimized.
19. Carburetor float height may be adjusted by means of bending the small tab on the float arm.
20. Throttle cable cap on the top of the carburetor must be used and properly installed in tight
position.
21. Choke must be OEM unaltered, but lever may be fastened open with a spring, rubber band,
wire, etc.
22. Idle pilot jet is #32, hole size is .0130” no-go.
23. Main jet is #95, hole size is .0380”; 0.036" go, 0.039" no-go.
24. Main nozzle – OEM stock unaltered – hole size = .101 to .103". No drilling, reaming,
slotting or oblonging of hole.
25. Emulsion tube – OEM stock unaltered
(4) four small holes = .018" to .020"
(5) five big holes = .026" to .029"
26. Venturi Measurement: Vertical: .792" max
27. Horizontal: .615" max at widest part
28. Horizontal: .602" max at narrowest part.
29. Air pick off hole .057" go, .061" no-go.
30. Throttle bore – Must be as cast. .874" max bore diameter.
31. Venturi idle fuel hole .036" max.
32. Carburetor O-Ring part number B&S part # 555601 is required and must be unaltered.
33. Intake manifold max length = 1.740" to 1.760"
34. Intake manifold bore diameter = .885" to .905" max
35. Choke Bore 1.149" max.
36. Carb Slide Cutaway .075" no-go.
37. The ONLY head casting for the B&S LO206 herein is the ‘RT-1’, cast into the head just off
the head gasket surface (towards the rear of the engine, PTO side). The overall head
minimum thickness is 2.430”. Cylinder head must be “as cast”. Hard Carbon may be
scraped from head before measuring, but factory machining marks left on the head gasket
surface are a tech item.
38. Depth of shallow area of combustion chamber must be .030" minimum, as measured with a
depth gage on both the combustion side and spark plug side of cylinder head.
39. Width of combustion chamber at the widest part across the valve seats area checked with a
2.640” no-go at a depth of 0.200” in the combustion chamber.
40. Depth at floor of combustion chamber is .340" minimum.
41. Valve maintenance may be performed, however Valve seats must remain factory
specification with one 45 degree angle only. Multi-angle valve seats are not permitted.
42. Unaltered B&S part #555552 (exhaust) and #555551 (intake) can be checked for
appearance, weight, and dimensions.
43. Valve surface must be unaltered factory ground and have one 45 degree sealing surface
only. There will be no other angles ground on any part of the valve.
44. No machining, polishing, easing, or titanium valves allowed.
45. Inspect retainers for alterations that would increase valve spring pressure; .055" to .075"
flange thickness.
46. Both intake and exhaust must have OE stock B&S valve keepers.
47. Replacement of valve guides with B&S part #555645 only is allowed.
48. Maximum depth from the head gasket surface to the intake valve guide is 1.255”.
49. Unaltered B&S part #555723 is the only head gasket allowed. Minimum gasket thickness
between head bolt holes .049". Measurements are to be made with a micrometer in four
places between the head bolts, from the inside of the gasket.
50. No de-burring, machining, honing, grinding, polishing, sanding, media blasting, etc. of
ports.No alterations of any kind may be made to the intake or exhaust ports. The transition
from intake bowl to port must have factory defined machining burr at this junction. No
addition or subtraction of material in any form or matter.
51. Intake Port Maximum diameter measurement = .918" max.
52. Exhaust Port must be as cast factory stock. Exhaust Outlet .980" max.
53. Intake and Exhaust valve seats must be 45 degree angle only, per factory specifications.
Multi-angle valve seats are not permitted.
54. Intake valve seat diameter inside = maximum .972"
55. Intake port pocket bowl (area just below valve seat) = .952"
56. Exhaust valve seat diameter inside = maximum .850"
57. Intake valve:
a) Minimum Weight of Valve 29.26 grams
b) Diameter of valve stem .246 to .247"
c) Diameter of valve head 1.055 to 1.065"
d) Inside Diameter of valve seat .972" maximum
e) Valve length Minimum 3.3655"
f) Height from angle of valve face to top of the valve .057" minimum
58. Exhaust valve:
a) Minimum Weight of Valve 28.62 grams
b) Diameter of valve stem .246 to .247"
c) Diameter of valve head .935 to .945"
d) Inside Diameter of valve seat .850" maximum
e) Valve length Minimum 3.3655"
f) Height from angle of valve face to top of the valve .060" minimum
59. Valve Springs are single coil stock, unaltered B&S part # 26826. Must be identical in
appearance to factory part and have 4.25 to 4.75 coils in stack.
a) Spring Wire Diameter: .103" to .107"
b) Valve spring length: .930" max
c) Inside diameter: .615" to .635"
60. Rocker arms must be unaltered stock B&S part #691230 (US) or #797443 (metric) and will
not be altered in any way.
61. Rocker studs must be stock, unaltered stock B&S part #694544 (US) or #797441 (metric)
and in stock location. No bending of studs.
62. Rocker Ball must B&S stock. Diameter .590" to .610"
63. Rocker arm mounting positions may not be altered in any manner.
64. Rocker arm stud plate must be bolted to the head with one, OEM stock B&S gasket only
with no alterations. Maximum thickness of gasket is .060 inches.
65. Rocker arm overall length 2.865" minimum.
66. Push rods must be unaltered stock B&S part #555531.
67. Push rod length is 5.638" to 5.658"
68. Push rod diameter is .185" to .190"
69. Engine block must be unaltered “as cast” B&S factory machined condition.
70. There must be no addition or subtractions of metal or any substance to the inside or outside
of the cylinder block.
71. Cylinder bore cannot be bored oversize
72. Cylinder bore cannot be re-sleeved.
73. Cylinder bore position is not be altered, moved, or angled in any manner.
74. Cylinder bore inside dimension (stock bore is 2.690”) is 2.693” maximum for entire length,
top to bottom.
75. Crankcase and cover must be B&S stock, unaltered, “as cast in factory” condition.
76. Block deck gasket surface finish is not a tech item. Angle milling or peak decking is not
allowed.
77. Piston pop up can be .005" maximum. Piston pop-up to be checked with flat bar in center of
piston parallel to piston pin and then again checked 90 degrees to piston pin.
78. Carbon build-up can be removed before pop-up is measured as long as material is not
removed from the piston. De-burring of the manufacturing part number/marks is permitted
as long as:
(a) Removal does not extend beyond the defined script area.
(b) De-burring does not extend below the original piston surface area.
(c) The original part numbers and script are still clearly visible.
79. No alterations or subtractions of metal or any other substance to crankcase cover.
80. Maximum crankshaft stroke is 2.204”. Push piston down to take up rod play, then check
stroke from BDC to TDC.
81. Camshaft Tech:
a) Maximum valve lift is checked from the top of the valve spring retainer.
b) Valves must be adjusted to zero clearance. The movement of the valve spring retainers may
not exceed .255".
c) Camshaft Profile Limits are to be measured at the push rod.
d) Procedure: Push gently down on dial indicator stem to ensure that there is no lash when
push rods are going down.
Intake Lift Degrees
0.006 59 to 49 BTDC
0.020 16 TO 12 BTDC
0.050 .5 TO 4.5 ATDC
0.100 17 TO 21 ATDC
0.150 33.5 TO 37.5
0.175 43 TO 47 ATDC
0.200 54 TO 58 ATDC
0.225 68 TO 72 ATDC
MAX LIFT 0.257
MIN LIFT 0.252
0.225 38 to 34 BBDC
0.200 24.5 TO 20.5
0.175 14 TO 10 BBDC
0.150 4.5 TO .5 BBDC
0.100 12 TO 16 ABDC
0.050 29 TO 33 ABDC
0.020 45.5 TO 49.5
0.006 81 TO 91 ABDC
Exhaust Lift Degrees
0.006 101 to 91 BBDC
0.020 59 TO 55 BBDC
0.050 43 TO 39 BBDC
0.100 26 TO 22 BBDC
0.150 9 TO 5 BBDC
0.175 1 TO 5 ABDC
0.200 11.5 TO 15.5
0.225 25 TO 29 ABDC
MAX LIFT 0.259
MIN LIFT 0.252
0.225 76 TO 72 BTDC
0.200 62.5 TO 58.5
0.175 52 TO 48 BTDC
0.150 42 TO 38 BTDC
0.100 25.5 TO 21.5
0.050 8.5 TO 4.5 BTDC
0.020 8 TO 12 ATDC
0.006 (no check)
82. No modifications are allowed to the flywheel. Minimum weight of the flywheel, fins and
attachment bolts is 4 pounds 1 ounce. Stock B&S part #555683 only.
83. No machining, glass beading, sand blasting, painting or coating of flywheel is allowed.
84. A flywheel fan, B&S part #692592, with broken fins must be replaced.
85. Stock, unaltered B&S flywheel key with the B&S logo is required. Width of the key
allowed is .1825”-.1875”. No offset keyways allowed.
86. Unaltered B&S stock ignition part #555718 is mandatory in all classes except Kid Karts.
Only “GREEN” ignition module allowed. Maximum RPM: 6,150.
87. Kid Karts LO206 class requires the use of unaltered B&S stock ignition part #555725
(BLACK in color). Maximum RPM: 4,150 with 50 RPM tolerance.
88. Coil may not be altered. Coil position, other than air gap may not be altered in any way.
Coil air gap is non-tech (recommended clearance .0140”).
89. Ignition switch and wires must remain in stock location. No alterations to ignition switch or
wiring are permitted.
90. Coil mounting bolts must be stock and cannot be altered in any way to advance or retard
timing. Attachment bolts and/or bolt holes may not be altered.
91. Ignition timing maximum: 30 degrees BTDC
92. An unaltered B&S factory spark plug part number #555737 (Champion RC12YC) is the
only spark plug permitted. Spark plug must have the Champion and Briggs & Stratton logo
as well as the RC12YC identification on the insulator. Spark plug gap is non-tech.
93. Sealing washer must be in place as from factory.
94. Only the OEM B&S part #555714 Spark plug connector is permitted.
95. Recoil starter, B&S part # 695287, must be retained, as produced and intact. Starter may be
rotated.
96. All LO206 classes must run the RLV #5506 or 5507 Exhaust Header Pipe.
97. The use of a Header support brace is mandatory.
98. Gasket and/or silicone are allowed to seal header to head. (One gasket maximum)
99. Studs or bolts are permitted to fasten head to head. Bolts or nuts must be safety wired.
100.
Exhaust Silencer must be RLV B91XL (part number 4104) with round baffle holes
only.
101.
Safety wiring of the silencer to header is recommended.
102.
The exhaust header and silencer must be completely wrapped with a non-asbestos
insulation material starting approximately 2 inches from the exhaust flange.
103.
Kids Kart (Junior LO206 engine) class must use the B&S supplied Max-Torque
clutch, part #555727. No alteration to the clutch is allowed, except springs.
104.
Rookie, Sportsman, Junior and Non-Restricted LO206 Classes can run any rim
centrifugal clutch with a maximum of 9 springs and 6 shoes. No alteration to clutch
allowed, except springs. Clutch coolers are not allowed.
105.
The use of a chain guard is mandatory.
9.9 USKRA, LLC Gas Animal Classes
475 Gas Animal
Engine: Briggs & Stratton Gas Animal Engine. Green Restrictor Plate – 0.475”
(Hole No Go size 0.476”)
Minimum Weight: 280 lbs.
620 Gas Animal
Engine: Briggs & Stratton Gas Animal engine. Orange Restrictor Plate
Minimum Weight: 320 lbs.
Adult Gas Animal
Engine: Briggs & Stratton Gas Animal engine.
(Non-Restricted Classes will be offered in Ultra Light, Light, Medium, Heavy, Super Heavy, and
Sumo minimum kart + driver weights)
1. All parts must be Briggs & Stratton Series 12 Engine Model Number 124332 factory
production parts unless otherwise specified in this manual. No machining or alteration of
parts is permitted unless specifically noted. All parts are subject to comparison to a known
stock Briggs & Stratton part.
2. The engine will be sealed with two wires; one wire will run between a valve cover bolt and
a intake to engine bolt to a the nut side of a carb to intake bolt; the other wire seal will seal
the front side cover bolt.
3. Engine shroud and covers and control bracket must be intact and may not be modified,
except control cover which can be modified to attach throttle bracket and fuel pump.
Cylinder cover cannot be cut, trimmed or modified for head temperature thermocouple,
intake manifold or exhaust header flange clearance.
4. The stock kill switch is not mandatory, however, if installed, the stock kill switch must
remain in stock location.
5. Briggs & Stratton Air Shield/Guard Part # 555699 may replace plastic control cover and
control bracket.
6. Flywheel guard is mandatory. All flywheel guards must be bolted to blower housing.
Flywheel guard may not be taped or covered. Briggs & Stratton Part # 555255 plastic
flywheel guard shield is the only approved cover and must be factory unaltered.
7. Air hole diameters:
a) Large center hole – 2.125” min
b) 2 Medium holes - .350” min
c) 12 Small holes - .225" min
8. Studs are allowed for header pipe attachment to cylinder head.
9. The carb may be attached to the intake with any 1/4” bolts, but studs are not allowed.
10. Stock head bolts must be used and four are mandatory. All other external metric bolts may
be replaced with American standard bolts of the appropriate size. Any bolt(s) used to
secure sheet metal may be replaced with larger diameter bolt(s), except the sheet metal
secured by the head bolts.
11. An Extra Heat Shield located above the chain guard is allowed. Shield may be no higher
than a level plane to the top of the valve cover.
12. The only approved header is RLV # 5511. Header must be used as manufactured by RLV
with no alterations or modifications.
13. EGT and O2 Sensors may not be installed in header pipe.
14. Exhaust pipe/header and silencer must not extend past rear bumper and have no exposed
sharp edges. Header pipes MUST be wrapped or sleeved externally to protect driver from
burns.
15. Header may be sealed to cylinder head with gasket and/or silicone.
16. All headers must be constructed of continuous length from flange to end of pipe with stages
and/or welds permitted (no chamber, infusers, or covers of any type allowed on muffler
etc.).
17. A header support brace and safety wiring of header bolts or studs is mandatory. Safety wire
must be wrapped around pipe to ensure that bolts remain with the pipe in case they are
stripped out of the block. The maximum thickness of the header to block flange is 0.312”
18. The RLV 8-91 muffler is mandatory at all events where a silencer is required. At events
which are "open header", an optional "clamp-on" flared safety tip with no sharp edges is
allowed, and must be securely installed. At events requiring a muffler, the muffler must be
used as produced with no modifications or alterations permitted. Silencer must be tight,
secure, and completely intact on the header through out the entire event. Silencer must be
clamped to header tube; No welding of silencer to header. Silencer Baffle holes must all
measure 0.1285” maximum.
19. Any air filter is permitted. Air filter must be installed directly to carburetor. No filter
adapter allowed. Filter may not be used as an air ram and must filter from all areas as raced.
No alterations or additional open areas in filter allowed. A Pre-Filter can be used to cover
the air filter.
20. PZ Model 22 Carburetor only. Carburetor must remain stock as from factory unless
otherwise allowed in these specifications. Exceptions: Any size main jet can be used. Main
jet can be drilled or reamed to any size hole.
21. The float can be adjusted to any height by bending the small tab on the float arm.
22. Carb to intake seal is by O-Ring only. No sealer allowed. All air must enter engine via the
carburetor air horn.
23. Choke must be the factory stock part with no alterations.
24. The choke arm may be secured in the open position.
25. An adapter may be installed on end of carburetor fuel inlet to attach ¼” fuel line.
26. The float and needle must be present and stock as produced by manufacturer, in their stock
locations and function as intended; No additional parts may be added.
27. The fuel nozzle must extend between 0.040” and 0.060” into the venturi. The nozzle must
maintain stock configuration on top with no notching, chamfering or grinding.
28. Maximum throttle bore inside dimension is 0.874” No-Go. Throttle Bore must be
"as-cast".
29. Maximum choke bore inside dimension is 1.149” No-Go. Choke Bore must be "as-cast".
30. Carburetor venturi vertical dimension is 0.792” No-Go.
31. Carburetor venturi horizontal dimension is 0.618” No-Go for top and bottom of venturi at
the widest point.
32. Horizontal maximum is 0.605” No-Go for the narrowest part of venturi (center).
33. When measured from the front (air filter) side of the carburetor, the vertical (0.792”)
No-Go shall be held parallel with the carburetor bore, and the horizontal 0.618” and 0.605”
No-Go gauges cannot enter the venturi area.
34. When measured from the back (intake manifold) side, the No-Go gauge cannot start into
the venturi.
35. No alteration of the venturi is allowed.
36. Air pick-off hole is 0.061” No-Go.
37. Slide must be stock as from the factory, with no grinding or other alteration.
38. Deepest part of cut-away at bottom of slide must be a maximum of 0.074”.
39. Depth of cutaway may be measured by placing slide on a flat surface and attempting to
insert a 0.075” No-Go into the cut-away. Depth may be measured with slide in carburetor
by backing the idle screw out such that the slide rests on the bottom of the venturi, and then
attempting to insert a 0.075” No-Go into cut-away.
40. Needle Jet length 1.677" to 1.692”.
41. Taper on needle must remain stock and will be checked at 0.500” from the tip of the needle
and must not be smaller than 0.070” NO-GO.
42. The metal choke lever cover must remain in place but may be secured with silicone or
epoxy sealer. Additional pin punching is allowed to tighten choke cover.
43. The air metering hole must be round and have no chamfer or break and may not be
relocated it must remain as produced from factory.
44. The venturi floor idle fuel hole is 0.036” max and must be unaltered as from factory
production.
45. Jets must be stock configuration.
46. The main jet center hole can be drilled or reamed to any size.
47. Needle jet can be set at any notch.
48. Pilot jet hole size is 0.0130” No-Go.
49. Any size Main Jet hole is allowed.
50. Main Air Jet hole size is 0.0620” No-Go.
51. Main Nozzle hole size is 0.103” No-Go.
52. Emulsion tube must be stock unaltered with 4 small holes 0.018” min to 0.020” max
diameter.
53. Emulsion tube 4 big holes are to be .026” min to .028” max diameter.
54. Intake restrictor plate is to be unaltered, and must be as originally manufactured. Restrictor
plate must be flat and placed between carburetor and intake and sealed within gasket area.
55. There must be one gasket only between the restrictor plate and the intake manifold.
Addition of material or funneling of gasket(s) not allowed. Any attempt to bypass or
modify restrictor is prohibited.
56. Anodizing may not be removed from restrictor plate.
57. A competitor's plate may be compared to a known stock plate and any tool necessary may
be utilized to determine plate legality.
58. Restrictor plate violations are considered an intentional attempt to cheat, and are penalized
as such.
59. Restrictor plates sizes are as follows:
60. 475 Gas Animal uses Green plate, 0.476" No-Go
61. 620 Gas Animal uses Orange plate, 0.621” No-Go
62. Stock Animal intake is to be as supplied from the factory. Gasket surfaces may be
machined, but the gasket surfaces must remain flat for proper gasket seal. Length must be
1.740” No-Go and 1.760 Must-Go.
63. The two intake-to-block mounting holes and one intake-to-carburetor mounting hole may
be drilled out and will be teched with a 0.328” No-Go, and the width of the intake to
carburetor slotted hole will be checked with the same No-Go.
64. Intake manifold inside diameter is 0.885” Must-Go and 0.905” No-Go. Minor paint runs or
welding slag inside manifold are not grounds for disqualification.
65. Aftermarket intake-to-block gaskets are allowed, but sealants are not allowed. Maximum
gasket thickness is 0.070”.
66. An auxiliary, single diaphragm, pulse-type fuel pump is allowed. Fuel pump must be
externally mounted on engine and visible.
67. Fuel pump must be pulsed only from the crankcase upper oil fill cap. Crankcase pulse
fitting must have a thru hole in center. No restrictors and/or check valves can be mounted
in pulse fitting. Pulse line length from crankcase to fuel pump may not exceed 7”.
68. Fuel pump pulse line must be standard 1/4” inch inside diameter fuel line. Fuel line must be
1/4” inch or smaller inside. Fuel lines must be run by the most direct route with no excess
line. Fuel lines must be secured at all connecting points with safety wire or cable ties.
69. A fuel pump return line to fuel tank is not allowed.
70. Stock valve cover as supplied from factory, including the breather hole for the tube that
runs to the catch can (No threading of hole allowed).
71. Valve cover gasket may be aftermarket but must be of stock configuration; No sealer
allowed. Rocker arms must be stock as supplied from the factory. Minimum length is
2.865” No-Go.
72. The Bordeaux DynoCams ground "Pro Gas" camshaft must be used as-produced. Only
stock factory camshaft cores 555532 and 555584 from Briggs & Stratton are permitted.
73. Camshaft lobe profile readings must be taken from pushrod ends.
74. Profile the camshaft by setting the dial indicator at zero while the degree wheel is at TDC
on the compression stroke, and do not reset dial indicator during the profile reading
process.
75. Maximum cam lobe base circle is .870".
76. Camshaft lobes must remain flat and of original width.
77. Camshaft must be as manufactured without any grinding, polishing, filing, machining, etc.
78. No addition or subtraction of material to camshaft.
79. Camshaft must have Briggs and Stratton Identification LOGO stamped on face.
80. Minimum valve lash "as-raced" is 0.003” for both Intake and Exhaust valves. A 0.003”
thick feeler gage must pass freely between rocker arm and top of valve stem. Valve lash
check may be performed at any time once the engine reaches tech, and prior to loosening
rocker arm nut. If the engine lash check does not pass the valve lash check, a maximum of
15 minutes will be allowed for the engine to cool, and if it does not pass when re-checked,
it is a "fail".
81. Maximum valve lift of 0.255” taken directly off the valve retainer at zero valve lash setting.
Profile the camshaft by placing the dial indicator on valve retainer, and then tightening the
ball rocker nut until you see indicator move 0.001” to 0.002” (this will assure that all the
lash is taken out of the valve to rocker arm clearance). When checking the lift off the valve
retainer, the only dial indicator holder that should be used is a three leg holder Sox



#AT320A or similar indicator holder. Set the dial indicator to zero and then check all lift
and degree points listed below.
82. Maximum Intake and Exhaust camshaft lobe duration specifications measured at push
rods:
267 max degrees @ .020”
237 max degrees @ .050”
115 max degrees @ .200”
Camshaft Degree Wheel Profile Limits
INTAKE
Lift
Degrees
0.020” 28º TO 24º BTDC
0.050” 13 TO 9º BTDC
0.100” 6º TO 10º ATDC
0.150” 25° TO 29° ATDC
0.175” 36º TO 40º ATDC
0.200” 48° TO 52° ATDC
0.225” 63º TO 67º ATDC
MINIMUM LIFT 0.252”
MAXIMUM LIFT 0.257”
0.225” 34º TO 30º BBDC
0.200” 19° TO 15° BBDC
0.175” 6° TO 2° BBDC
0.150” 5º TO 9º ABDC
0.100” 23º TO 27º ABDC
0.050” 42º TO 46º ABDC
0.020” 57º TO 61º ABDC
EXHAUST
Lift Degrees
0.020” 65º TO 61º BBDC
0.050” 50º TO 46º BBDC
0.100” 30º TO 26º BBDC
0.150” 11º TO 7º BBDC
0.175” 1º BBDC TO 3º ABDC
0.200” 12º TO 16º ABDC
0.225” 28º TO 32º ABDC
MINIMUM LIFT 0.252”
MAXIMUM LIFT 0.257”
0.225” 69º TO 65º BTDC
0.200” 54º TO 50º BTDC
0.175” 42º TO 38º BTDC
0.150” 32º TO 28º BTDC
0.100” 13º TO 9º BTDC
0.050” 6º TO 10º ATDC
0.020” 21º TO 25º ATDC
83. Ball Rockers must be stock as from factory.
84. Push rods must be stock as from factory.
85. Briggs & Stratton and aftermarket head gaskets as listed which meet specifications are
allowed. No aluminum or copper head gaskets allowed. Measurement is to be made with
micrometer in four places between head bolts.
86. Gasket sealer cannot be used on head gasket.
87. Briggs & Stratton part cylinder head gasket #555723 minimum thickness is 0.049”.
88. Briggs & Stratton fire ring cylinder head gasket #555698 minimum thickness is 0.042” on
the metal fire ring part of the gasket.
89. Aftermarket cylinder head gasket minimum thickness is 0.042”.
90. Cylinder Head Plate must be stock as from the factory.
91. Cylinder Head Plate Gasket must be stock configuration and 0.060” Max thickness.
92. Rocker Arm Studs must be stock as from the factory, and installed as per factory.
93. Stock valves only. Valve face must be one 45 degree angle. Valves may not be polished or
lightened. If the valve is cleaned, no material may be removed from the valve. No
alterations to surface finish or shape allowed. Tip of valve must be at 90 degrees to stem.
Keeper groove location must remain stock. Minimum intake and exhaust valve length
3.250”.
94. Intake valve diameter is 1.055” No-Go, 1.065” Must-Go. Depth of dish in valve must
measure from 0.099” to 0.119”. Height from angle of valve face to top of valve 0.057”
minimum using gauge A26 (Check using a depth micrometer from top of valve to the
gauge).
95. Exhaust valve diameter is 0.935” No-Go, .945” Must-Go. Depth of dish in valve must
measure from 0.084” to 0.104”. Height of angle of valve face to top of valve 0.060”
minimum using gauge A27 (Check using a depth micrometer from top of valve to top of
gauge).
96. Maximum valve spring length is 0.930” No-Go. Wire diameter must be between 0.103” to
0.107” as measured in three places on spring.
97. Inside diameter of spring is 0.615” to 0.635”. Must be identical in appearance to factory
part and have 4 to 4.5 coils in stack.
98. Valve Spring Retainers and Keepers must be stock as from the factory.
99. Retainer flange thickness must measure 0.055” to 0.075”.
100.
Stock Briggs & Stratton cylinder head part #555635.
101.
Machining of head gasket surface only allowed. No machining of ports allowed.
102.
Bosses on head may be tapped to allow for attachment of a header brace.
103.
Briggs Heat Dispenser #555690 is approved for use.
104.
Minimum depth of cylinder head at shallow part of head is 0.011”. The
measurement on the shallow side of the combustion chamber will be taken with a depth
gauge on the push rod side of an imaginary line drawn from dowel pin to dowel pin on the
valve side of the dowel; it will also be taken over the spark plug area. The rest of the recess
area in the head has no depth dimension, but the recess must remain visible.
105.
Minimum Depth at the floor of head is 0.319”. Carbon buildup may be removed
from head at check locations prior to inspection if necessary to meet depth specifications.
A razor blade may be used to remove the carbon, but aluminum may not be removed from
the head surface.
106.
Maximum depth to top of valve seat is 0.360”. RT-1 head minimum depth is
0.320”. Old style head minimum depth is 0.335”.
107.
Cylinder Head thickness measured from head gasket surface to head plate gasket
surface is 2.405” minimum on RT-1 heads, and 2.420” minimum on old style heads. Head
thickness is checked in four places through the valve guides and the push rod holes with
gauge. Calipers may not be used.
108.
Width of combustion chamber at the widest part across the valve seats area is
checked with a 2.640” No-Go at a depth of 0.200” in the combustion chamber.
109.
The maximum diameter of the combustion chamber bowl is 0.951” checked with a
0.952” No-Go gauge parallel to the intake port.
110.
There must be only one angle on valve seats; 45º.
111.
Stock Briggs & Stratton valve seats are mandatory.
112.
Intake seat inside diameter is 0.966” Must-Go, 0.972” No-Go.
113.
Exhaust seat inside diameter is 0.841” Must-Go, 0.850” No-Go.
114.
Ports must be of stock configuration with no porting or modifications of any kind
allowed. There must be a single 45 º angle with a defined edge at the transition between end
of intake port and the bowl behind the valve.
115.
Media blasting of the ports is not allowed.
116.
Intake Inlet: 0.918” No-Go when checking 90 degrees to stud pattern, No-Go will
be straight; when checking in line with stud pattern, No-Go will set on floor of port at
bottom and stop at upper edge of port on top.
117.
Intake Port: 0.864” No-Go cannot touch the valve guide of the intake port. An
0.860” plug gage will be used as a visual check of the eyebrow area. This is not a No-Go
but a visual assist tool.
118.
Exhaust Port Maximum diameter is 0.980” No-Go. The port is legal if,
a) there is at least one entry point to the port where the No-Go gauge cannot enter the
port, and
b) the port is as supplied from the factory with no grinding or alteration.
119.
Stock valve guides as supplied from factory, or Stock replacement guide part #
555645 is allowed.
120.
Maximum depth from cylinder gasket surface to top of intake valve guide is 1.255”.
121.
Machining of the deck surface is permitted. No peak decking allowed.
122.
Piston pop-up cannot exceed 0.005” above block surface in the center of the piston.
When measuring piston popup, it should be accomplished with bar stock on a parallel with
the piston wrist pin and, using a dial indicator check the piston pop-up in this area. Then,
without moving the dial indicator, rotate the bar 90 degrees on the center line of the piston
and check the popup; it should not exceed 0.005”. Carbon build up on piston top may be
removed prior to checking piston pop up if necessary to meet 0.005” spec.
123.
No circular or machined grooving of cylinder is allowed in any position of cylinder.
Maximum cylinder bore is 2.693”.
124.
Factory stock crankshaft mandatory. Crankshaft Stroke is 2.204” Maximum, and
may be checked with a stroke pin or dial indicator. Stroke is checked by pushing piston
down to take up play of rod clearance. Stroke is checked from bottom dead center (BDC) to
top dead center (TDC).
125.
Stock factory timing gear mandatory and must be installed properly. Lightening,
polishing of counter weights or addition of metal or other material is not permitted. Offset
crankshafts are not permitted.
126.
Crankshaft journal diameter is 1.094” - 1.100”.
127.
Aftermarket crankshaft bearings of non self-aligning type, with or without shield,
are permitted. No ceramic bearings allowed.
128.
Shims, if used, must be installed as from factory.
129.
Recoil starter and cup cannot be used and must be removed. Any style flywheel
electric starter nut and washer can be used as long as it does not protrude beyond the end of
the crankshaft end face and the maximum diameter of the nut does not exceed 1.25 inches.
130.
PVL flywheel Briggs Part # 555683, and Plastic flywheel fan part #692592 only.
131.
PVL flywheel minimum weight: 4lbs. 1oz.
132.
Flywheel key is optional.
133.
No machining, glass beading or sandblasting of flywheel is allowed.
134.
PVL Magneto Briggs Part # 555681 only. No slotting of mounting holes or
machining of attaching bolts is permitted.
135.
Spark plug connector must be stock factory type. Rubber plug boot is allowed.
136.
Champion Spark Plug Part #RC12YC only. The plug must be stock as produced
from factory with no modifications.
137.
No tech on Spark plug electrode gap.
138.
A sealing washer or a cylinder head temperature sensor must be used.
139.
Crankcase Side cover must remain stock. A maximum of two crankcase gaskets are
allowed. Aftermarket crankcase side gaskets are permitted however, must be of same size
and material as stock gasket(s).
140.
Stock Briggs & Stratton valve lifters as supplied from factory are mandatory. Head
of lifter 0.820” No-Go, 0.860” Must-Go. Length of lifter 1.515”, No-Go, 1.525” Must-Go.
141.
Stock Animal, World Formula or WKA approved commercially available billet
aluminum connecting rod with or without inserts are allowed. No titanium rods allowed.
Maximum oil hole is 0.185”. No polishing or grinding on the rod.
142.
No modifications to the rod except crank bore and pin bore can be honed. Rod
length is 2.414” minimum, 2.429” maximum as measured from bottom of wrist pin to top
of crankshaft journal. Minimum weight is 130 grams.
143.
Stock rod length is 2.419” minimum, 2.429” maximum. Measured from bottom of
wrist pin to top of crankshaft journal.
144.
Oil hole opening in stock, World Formula and aftermarket billet rods is 0.185”
No-Go.
145.
For identification purposes rod must be marked with either a Registered Trade
Mark or manufacturer's name.
146.
Briggs & Stratton Animal standard bore piston only part # 555660.
147.
Piston must be unaltered and conform to the specifications listed below. Piston
Wrist Pin bore must not be altered or relocated except minimum honing of wrist pin bore
allowed. New style Briggs & Stratton piston with circlip on both sides of wrist pin bore
allowed. Deck above top ring must not be altered. Machining of the piston is not allowed.
Arrow must point toward flywheel.
148.
Top of piston to wrist pin bore must be 0.658” minimum as measured on circlip
side of piston.
149.
Minimum piston length is 1.762”.
150.
Piston Wrist pin must not be altered.
151.
Maximum inside dimension of wrist pin is 0.414” measured at outside edge.
152.
Outside dimension is 0.624” to 0.626”.
153.
Minimum length, 1.901".
154.
Three piston rings are mandatory.
155.
Compression/Top ring chamfer must face up, and must remain as manufactured.
156.
Scraper Ring must be installed with inside chamfer down.
157.
Minimum width top two rings 0.095”.
158.
Thickness top two rings 0.059” to 0.064”.
159.
Stock oil ring must be installed as from factory.
160.
Oil ring minimum width 0.065”, ring groove must be present. Expander ring must
be installed. Oil ring expander minimum length is 8.200”.
161.
Oil ring Thickness 0.098” to 0.102”.
162.
Rings must be self-supporting in the cylinder bore of the engine being teched.
163.
Ends of ring must remain flat.
164.
Excessive end gapping of rings not allowed.
165.
Rings must conform to all listed factory specifications and be of stock
configuration. Known standards for piston/ring configurations are Briggs & Stratton
factory approved parts.
166.
No machining of rings allowed except via lapping and end gapping.
167.
Oil ring expander ring must be as produced from factory. The oil expander ring
minimum length is 8.200".
168.
Rings must be in one piece when removed from block.
169.
Block must be as produced from Briggs and Stratton with no alterations or
reworking. Blocks repaired from broken rod damage are permitted providing that repair
does not constitute a performance enhancing modification. No welding can be done to an
engine from the cooling fins upwards. Cam boss repair or welding not allowed. External
welding of block is only allowed to repair damage from broken rod. One coil post may be
repaired as long as the remaining post is factory and unaltered. No knurling of guides
allowed. The hole between the valve lifters shall be a maximum of 0.250” No-Go.
170.
Tape on block is not allowed.
171.
Dry disk or shoe type engine mounted clutch only.
9.10 Yamaha KT-100 Stock
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Class Weight: The only weight being offered at this time is “Heavy”; 390lbs.
Engine: Yamaha KT100S 2 cycle, single cylinder, piston port.
Bore: 2.087” maximum.
Stroke: 1.816” maximum.
1. All internal parts must be finished as per Yamaha Factory specifications unless specified.
2. No internal additional material may be added except in the case of engine repairs and shall
only restore engine or components to original specifications. The cylinder may not be
repaired in any of the port or passage as cast areas.
3. External modifications which do not in any way enhance performance are legal.
4. The crankcase ports will remain as cast. The minimum distance measured across the widest
section of the transfer ports shall be 3.835” minimum.
5. It is permissible to repair crankcase main bearing recesses by welding or with metal inserts.
6. All machined surfaces may be re-machined as long as engine is within any other
specifications within these rules. Due to manufacturing procedures, some cylinders have
some minor grinding on the transfer divider bridges and some evidence of casting
irregularities removed in transfer passages, this includes the transfer area in the crankcase.
7. Cylinder Head must be an original Yamaha casting
8. Combustion Chamber Minimum Volume is 11.00 cubic centimeters. Combustion chamber
must be spherical in shape with a visible squish band.
9. Welding and re-machining of the combustion area, gasket face is allowable.
Additions/repairs must be permanent and nonadjustable. This may include an aluminum
insert. Maximum diameter of any part of such repair insert is 2.5”.
10. The combustion chamber style is required to have a squish band and chamber which are
visually concentric to the spark plug.
11. The combustion chamber/squish area shall not protrude beyond the gasket sealing face of
the cylinder head.
12. The cylinder head spark plug thread may be repaired but must retain its original position in
relation to crankshaft axis.
13. Helicoils and similar are permitted.
14. Maximum distance from sealing surface of spark plug to combustion chamber sealing face
shall be 1.280”.
15. Repairs to the spark plug sealing face must be by addition of weld material only and
re-machining to a flat surface.
16. Cylinder head gasket: must be installed and made of aluminum or copper only; Maximum
outside diameter is 2.580”
17. Gaskets and Fasteners are non-tech items unless noted otherwise.
18. Exhaust: The only approved exhaust is an unaltered TSOW 10 degree exhaust available
from TS Racing.
19. It is permissible to stiffen the exhaust flange, but stiffening must not interfere with the
fitting of exhaust seals.
20. Modifications to fit an exhaust probe are permissible. A maximum of one (1) Exhaust
probe/fitting is permitted.
21. Exhaust header studs must remain in their original position.
22. Exhaust System must be designed so that exhaust gases are carried away from, and to the
rear of the driver.
23. Exhaust gases must all pass through the exhaust header pipe and the muffler and silencer at
all times.
24. The open end must point in such a way so that it does not present a hazard to other drivers.
25. Exhaust is to be securely mounted to a mounting bracket cradle and to the header pipe of
the engine
26. It is permissible to use, externally, heat proof wrapping between the springs and exhaust
cradle and the springs and flex.
27. Any accidental damage (when all gasses still pass through the exhaust system) does not
constitute a disqualification.
28. With the exception of repair to fixing points, any attempt to repair damage by cutting,
welding or fabrication will automatically make the exhaust illegal.
29. Grinding of all port surfaces to dimensions listed is allowed. Surface finish of all ports is
non-tech.
30. .Inlet Tract Length: 2.600” to 2.700”; Carburetor base gasket is to be removed for
measurement.
31. Intake Port Opening Dimension: .775” ATDC maximum.
32. Exhaust Port Opening Dimension: 1.155” ATDC min.
33. Spark plugs reach must measure .790” maximum without crush washer as shown below.
34. Approved flywheels are Yamaha part numbers 7F6-85551-00, 7F6-85551-50 (Old style),
35. 7F6-85551-01, 7F6-85551-51 and 7F6-85510-03-00 (New style).
36. Flywheel outside diameter must be 2.350” minimum.
37. New style flywheel thickness over (3) lugs .950” minimum, all other areas .817” minimum.
38. Old style flywheel thickness .827” minimum.
39. New style lug length, (3) places .750” minimum.
40. No tech on Flywheel and crankshaft keyway width, and key is non tech.
41. Ignition module must be original Yamaha, PRD or Atom, stock appearing, unaltered,
however silicone or epoxy is allowed to repair damage.
42. Coil may be repaired with silicone or epoxy.
43. Approved pistons are Yamaha, Burris, Wiseco, Vinart, and KSI RKE-787. All approved
pistons must have visible manufacturer’s name cast inside.
44. Piston coatings allowed.
45. Piston skirt length must be the same within .015” front to back. The piston skirt length may
be machined to meet specifications. Maximum .030” piston skirt corner break, measured
axially
46. Piston must be domed.
47. Piston Rings must be manufactured of ferrous material. Wrist pin length is 1.560”
minimum.
48. Piston Wrist pins must be manufactured of ferrous material. Piston Wrist pin outside
diameter .550” minimum, .555” maximum.
49. Wrist pin inside diameter .410” maximum.
50. Approved connecting rods are Yamaha part numbers 7F6-11651-01, 7F6-11651-02 and
50W-11651-00 only. The connecting rod must be of an OEM part, and stock appearing.
51. No machining, grinding, blending or polishing is allowed, however Shot-peening the
connecting rod is allowed.
52. Center of crankshaft journal diameter to center of wrist pin diameter is 3.930” to 3.945”.
53. Top or bottom-guided rods and bearings allowed.
54. Bearings and spacers are non-tech items
55. Crankshaft must be OEM only or KSI meeting all stock specifications. Crankshaft outside
diameters must measure 3.410” to 3.435”.
56. It is permissible to recondition the crankshaft main shaft by plating.
57. It is permissible to repair the drive side crankshaft end, where the threaded section has
broken off by drilling and tapping the centre of the crank to accept an M6 or M8 screw.
58. Width over bearing lands is 1.790” minimum.
59. Concentric bushings may be added to repair damaged crankshaft journals.
60. Removal of material in bearing recess area is allowed for bearing clearancing only, not for
lightening or balancing purposes.
61. Crankpins are non-tech.
62. Inside width between counterweights is .340” minimum.
63. Carburetor must be a Walbro WB3A or WA55B only.
64. Carb body, throttle shaft and butterfly must be stock appearing, however, polishing of the
venturi, air horn and throttle bore is allowed.
65. Metering holes are non-tech.
66. Unless specified, non-tech items are to be of the same type and style as the original. No
alteration from the original manufacturer's specifications is permitted to fit a non-tech item.
Other non-tech items are filter cups, air boxes and air filters gaskets, pulse pipe and tube,
seals, big end roller/cage, little end spacers, rings, washers, cages, fasteners, fulcrum spring
(carburetor meter levering spring), spark plug and spark plug lead and cap, gudgeon pins,
main bearings, and coolant sealing “O” rings.
67. Engine must utilize a wet or dry disc engine mounted clutch only.
68. Other legal additions to the engine are limited to the following: Chain guard, motor mount,
extension of carb jet needles, carb return springs, third bearing and adapter.