STIH)
STIHL BR 500, 550, 600
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2009-05
Contents
1.
Introduction
2
2.
Safety Precautions
2
3.
Specifications
3
3.1
3.2
3.3
3.4
Engine
Ignition System
Fuel System
Tightening Torques
3
3
3
4
6.
Fuel System
17
8.
Ignition System
44
6.1
6.2
6.2.1
6.2.2
Air Filter
Carburetor
Leakage Test
Removing
and Installing
Servicing
the Carburetor
Metering Diaphragm
Inlet Needle
Pump Diaphragm
Accelerator Pump
Adjusting
the Carburetor
User Adjustment
Basic Setting in
Service Shop
Tank Vent
Fuel Hoses/
Pickup Body
Fuel Tank
17
19
19
8.1
8.2
8.3
45
45
20
8.4
20
20
21
22
23
8.5
8.6
Ignition Module
Ignition Timing
Testing the
Ignition Module
Removing and
Installing
Spark Plug Boot
Testing the
Wiring Harness
Ignition System
Troubleshooting
9.
Control Handle
52
9.1
9.3.2
Throttle Trigger/
Interlock Lever
Setting Lever
Throttle Cable
Removing and
Installing
Adjusting
10.
AV System
54
10.1
10.2
Spring Elements
Backplate
54
54
11.
Fan
55
11.1
11.2
11.3
11.4
Outer Fan Housing
Inner Fan Housing
Fanwheel
Antistatic Wire
55
56
56
57
12.
Special
Servicing Tools
58
Servicing Aids
59
6.3
4.
4.1
4.2
4.3
4.4
Troubleshooting
Rewind Starter
Ignition System
Carburetor
Engine
6.3.1
6.3.2
6.3.3
6.3.4
6.4
6
6
7
8
10
6.4.1
6.4.2
6.5
6.6
6.7
5.
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
Rewind Starter /
Shroud
General
Removing
and Installing
Pawl
Rope Rotor
Starter Rope/Grip
Rope Guide Bushing
Replacing
the Rewind Spring
Tensioning
the Rewind Spring
Shroud
26
27
28
29
11
7.
Engine
7.1
Compression
Pressure
Checking / Adjusting
Valve Clearances
Rocker Arms /
Pushrods
Cam Followers
Cam Gear
Decompression
System
Muffler/Spark
Arresting Screen
Flywheel
Testing for Leaks
Preparations
Vacuum Test
Pressure Test
Crankshaft
Oil Seals
Crankcase,
Lower Half
Crankshaft
Piston
Piston Rings
Valves / Valve
Springs
Upper Half of
Crankcase
with Cylinder
9.2
9.3
9.3.1
46
47
48
49
52
52
53
53
53
29
11
11
11
12
13
14
14
15
16
7.2
7.3
7.4
7.5
7.5.1
7.6
7.7
7.8
7.8.1
7.8.2
7.8.3
7.9
7.9.1
7.9.2
7.9.3
7.9.4
7.9.5
7.9.6
RA_452_00_01_02
25
25
8.7
45
7.9.7
29
30
31
32
33
33
34
35
35
36
36
37
38
38
13.
39
40
40
42
43
43
q
© ANDREAS STIHL AG & Co. KG, 2009
BR 500, BR 550, BR 600
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1
1.
Introduction
This service manual contains
detailed descriptions of all the
typical repair and servicing
procedures for this power tool.
2.
Symbols are included in the text and
pictures for greater clarity.
The meanings are as follows:
In the descriptions:
As the design concept of models
BR 500, BR 550 and BR 600 is
almost identical, the descriptions
and servicing procedures in this
manual generally apply to all three
models. Differences are described
in detail.
You should make use of the
illustrated parts lists while carrying
out repair work. They show the
installed positions of the individual
components and assemblies.
: = Action to be taken as
shown in the illustration
(above the text)
– = Action to be taken that is
not shown in the illustration
(above the text)
In the illustrations:
A Pointer
aDirection of movement
Refer to the latest edition of the
relevant parts list to check the part
numbers of any replacement parts.
A fault on the machine may have
several causes. To help locate the
fault, consult the chapter on
"Troubleshooting" in this manual
and the "STIHL Service Training
System" for all assemblies.
Refer to the “Technical Information”
bulletins for engineering changes
which have been introduced since
publication of this service manual.
Technical information bulletins also
supplement the parts list until an
updated edition is issued.
The special servicing tools
mentioned in the descriptions are
listed in the chapter "Special
Servicing Tools" of this manual.
Use the part numbers to identify the
tools in the "STIHL Special Tools”
manual. The manual lists all special
servicing tools currently available
from STIHL.
Safety Precautions
If the engine is started up in the
course of repairs or maintenance
work, observe all local and countryspecific safety regulations as well
as the safety precautions and
warnings in the instruction manual.
Gasoline is an extremely flammable
fuel and can be explosive in certain
conditions.
Improper handling may result in
burns or other serious injuries.
Warning!
Do not bring any fire, flame, spark or
other source of heat near the fuel.
All work with fuel must be performed
outdoors only. Spilled fuel must be
wiped away immediately.
b 4.2
Reference to another chapter,
i.e. chapter 4.2 in this example.
Service manuals and technical
information bulletins are intended
exclusively for the use of properly
equipped repair shops. They must
not be passed to third parties.
Always use original STIHL
replacement parts.
They can be identified by the
STIHL part number,
the STIH) logo and the
STIHL parts symbol (
This symbol may appear alone on
small parts.
2
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BR 500, BR 550, BR 600
3.
3.1
Specifications
BR 600
64.8 cm3 (3.95 ci)
50 mm (2.55 in)
33 mm (1.3 in)
5500 rpm
2500 rpm
64.8 cm3 (3.95 ci)
50 mm (2.55 in)
33 mm (1.3 in)
6100 rpm
2500 rpm
64.8 cm3 (3.95 ci)
50 mm (2.55 in)
33 mm (1.3 in)
7200 rpm
2500 rpm
0.5 bar
0.5 bar
0.5 bar
0.5 bar
0.5 bar
0.5 bar
0.15...0.3 mm
(0.006...0.012 in)
NGK CMR 6 H
0.7 mm (0.028 in)
0.15...0.3 mm
(0.006...0.012 in)
NGK CMR 6 H
0.7 mm (0.028 in)
0.15...0.3 mm
(0.006...0.012 in)
NGK CMR 6 H
0.7 mm (0.028 in)
Ignition System
Air gap between ignition module and fanwheel:
Spark plug:
Electrode gap:
3.3
BR 550
Engine
Displacement:
Bore:
Stroke:
Operating speed with nozzle:
Idle speed:
Crankcase leakage test
at gauge pressure:
under vacuum:
3.2
BR 500
Fuel System
Carburetor leakage test at gauge pressure:
Operation of tank vent at gauge pressure:
Fuel:
BR 500, BR 550, BR 600
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0.8 bar
0.8 bar
0.8 bar
0.3 bar
0.3 bar
0.3 bar
as specified in
as specified in
as specified in
instruction manual instruction manual instruction manual
3
3.4
Tightening Torques
DG and P (Plastoform) screws are used in polymer and lightmetal components. These screws form a permanent
thread when they are installed for the first time. They can be removed and installed as often as necessary
without impairing the strength of the screwed assembly, providing the specified tightening torque is observed.
For this reason it is essential to use a torque wrench.
Fastener
Thread size
For component
Torque
lbf.ft
Screw
Screw
Collar screw
Screw
Screw
Screw
Screw
Screw
Screw
Hub
Screw
Screw
Screw
Screw
Screw
Screw
Screw
Screw
Screw
Screw
Screw
Screw
Nut
Locknut
Screw
Screw
IS-P5x18
IS-P5x18
IS-M5x16
Shroud/filter housing/fan housing
Shroud/fan housing
Collar screw/cylinder/rocker arm
mounting
IS-DG5x16
Cover/cylinder
IS-M5x21
Filter cover/filter housing
IS-M5x48x22 Filter housing/carburetor/flange
IS-P5x18
Fan housing, outer/inner
IS-D6x32
Fan housing, inner/engine pan
IS-D6x32
Fan housing, inner/cylinder
IS-M12x1
Fanwheel/crankshaft
IS-P4x19
Handle molding, outer/inner
IS-P6x21.5
Handle moldings/blower tube
IS-M4x9.5
Scoop/muffler
IS-M6x30
Engine pan/cylinder, initial stage
IS-M6x30
Engine pan/cylinder, final stage
IS-DG5x24
Air guide shroud/fan housing
IS-DG5x24
Air guide shroud/engine pan
IS-P4x19
Detent spring/handle molding, inner
IS-P6x25
Backplate/bearing plug
IS-P6x25
Backplate/tank housing
IS-M5x18
Muffler/cylinder
IS-P6x21.5
Hose clip/blower attachment
IS-M8x1
Flywheel/crankshaft
IS-M5
Rocker arm mounting
IS-M5x18
Starter cover/shroud/engine pan
IS-M5x18
Starter cover/shroud/cylinder
Remarks
Nm
3.0
3.0
4.0
4.0
6.6
3.0
3.0
4.4
3.0
8.8
8.8
22.0
1.1
3.0
3.0
3.0
8.8
3.0
4.4
1.1
4.4
4.4
5.9
3.0
15.0
9.0
4.0
4.0
6.0
4.0
12.0
12.0
30.0
1.5
4.0
4.0
4.0
12.0
4.0
6.0
1.5
6.0
6.0
8.0
4.0
20.0
4.4
4.4
6.0
6.0
1)
2)
3)
3)
Remarks:
1) Install with high-strength Loctite 270
2) Do not lubricate with grease
3) Tighten in crosswise pattern
4
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BR 500, BR 550, BR 600
Fastener
Screw
Screw
Spark plug
Screw
Thread size
IS-P5x14
IS-M5x30
IS-M10x1
IS-DG5x20
For component
Harness/backplate
Valve cover/cylinder
Spark plug
Ignition module/cylinder
Torque
lbf.ft
Nm
3.0
4.4
6.6
4.4
4.0
6.0
9.0
6.0
Remarks
Use the following procedure when refitting a DG or P screw in an existing thread:
Place the screw in the hole and rotate it counterclockwise until it drops down slightly. Tighten the screw
clockwise to the specified torque.
This procedure ensures that the screw engages properly in the existing thread and does not form a new thread
and weaken the assembly.
Power screwdriver settings for
polymer:
Plastoform screws
max. 600 rpm
DG screws
max. 500 rpm
Important:
Do not mix up screws with and without binding head
BR 500, BR 550, BR 600
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5
4.
4.1
Troubleshooting
Rewind Starter
Condition
Cause
Remedy
Starter rope broken
Rope pulled out too vigorously as
far as stop or over edge, i.e. not
vertically
Fit new starter rope
Normal wear
Fit new starter rope
Rewind spring broken
Fit new rewind spring
Spring overtensioned – no reserve
when rope is fully extended
Fit new rewind spring
Very dirty or corroded
Clean or replace rewind spring
Guide pegs on pawls or pawls
themselves are worn
Fit new pawls
Spring clip fatigued
Fit new spring clip
Starter mechanism very dirty
Thoroughly clean complete starter
mechanism
Lubricating oil on rewind spring
becomes viscous at very low
outside temperatures (spring
windings stick together)
Coat rewind spring with a standard
solvent-based degreasant
(containing no chlorinated or
halogenated hydrocarbons). Then
pull rope carefully several times
until normal action is restored.
When installing, coat rewind spring
and starter post with STIHL special
lubricant
Starter rope does not rewind
Starter rope can be pulled out
almost without resistance
(crankshaft does not turn)
Starter rope is difficult to pull and
rewinds very slowly
6
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BR 500, BR 550, BR 600
4.2
Ignition System
Exercise extreme caution while carrying out maintenance and repair work on the ignition system. The high
voltages which occur can cause serious or fatal injuries!
Condition
Cause
Remedy
Engine runs roughly, misfires,
temporary low of power
Spark plug boot is loose
Press boot firmly onto spark plug,
and fit a new leg spring if necessary
Spark covered in soot, smeared
with oil
Install new spark plug
Wrong air gap between ignition coil
and flywheel
Reset air gap
Flywheel cracked or damaged or
pole shoes have turned blue
Install new flywheel
Ignition timing out of adjustment,
flywheel warped, key in flywheel
sheared
Install new flywheel
Flywheel magnetization weak –
pole shoes have turned blue
Install new flywheel
No spark
Check operation of setting lever
and ignition module
No spark
Faulty insulation on ignition lead or
short circuit wire. Use ohmmeter to
check ignition lead for break. If
break is detected or resistance is
high, fit new ignition lead
Engine does not run
Replace or clean spark plug,
replace damaged parts of ignition
system
BR 500, BR 550, BR 600
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7
4.3
Carburetor
Condition
Cause
Remedy
Carburetor floods, engine stalls
Inlet needle not sealing. Foreign
matter in valve seat or cone
damaged
Remove and clean or replace inlet
needle, clean fuel tank, pickup
body and fuel line if necessary
Inlet control lever sticking on
spindle
Free off inlet control lever
Helical spring not located on nipple
of inlet control lever
Remove inlet control lever and refit
correctly
Perforated disc on diaphragm is
deformed and presses constantly
against inlet control lever
Fit new metering diaphragm
Inlet control lever too high (relative
to design position)
Set inlet control lever flush with
upper face of housing
Idle jet too lean
Turn low speed screw (L)
counterclockwise (richer) no further
than stop
Main jet too lean
Turn high speed screw (H)
counterclockwise (richer) no further
than stop
Inlet control lever too low (relative
to design position)
Set inlet control lever flush with
upper face of housing
Inlet needle sticking to valve seat
Remove inlet needle, clean
and refit
Diaphragm gasket leaking
Fit new diaphragm gasket
Metering diaphragm damaged or
shrunk
Fit new metering diaphragm
Impulse hose damaged or kinked
Fit new impulse hose
Poor acceleration
8
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BR 500, BR 550, BR 600
Condition
Cause
Remedy
Engine will not idle,
idle speed too high
Throttle shutter opened too wide by
idle speed screw (LA), throttle
cable adjustment incorrect
Reset idle speed screw (LA), check
throttle cable adjustment
Engine leaking
Seal the engine
Idle jet bores or ports blocked
Clean jets and ports and blow clear
with compressed air
Idle jet too rich or too lean
Set low speed screw (L) correctly
Setting of idle speed screw
incorrect – throttle shutter
completely closed
Set idle speed screw (LA) correctly
Small plastic disc in valve jet does
not close
Clean or renew valve jet
Air filter plugged
Clean air filter
Throttle shutter not opened fully
Check throttle cable adjustment
Tank vent faulty
Clean or replace tank vent if
necessary
Fuel pickup body dirty
Clean or replace pickup body
Fuel strainers dirty
Fit new fuel strainers
Leak in fuel line between tank and
fuel pump
Seal or renew connections and fuel
line
Setting of high speed screw (H) too
rich
Turn high speed screw (H)
clockwise (leaner), no further than
stop
Main jet bores or ports blocked
Clean the carburetor
Pump diaphragm damaged or
fatigued
Fit new pump diaphragm
Engine stalls at idle speed
Engine speed drops quickly under
load – low power
BR 500, BR 550, BR 600
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9
4.4
Engine
Always check and, if necessary, repair the following parts before looking for faults on the engine:
–
–
–
–
Air filter
Fuel system
Carburetor
Ignition system
Condition
Cause
Remedy
Engine does not start easily, stalls
at idle speed, but operates normally
at full throttle
Check compression
Check combustion chamber
for excessive build-up of
combustion deposits, check
condition of valves and valve
clearance
Manifold leaking
Seal or replace manifold
Oil seals on crankshaft defective
Replace oil seals
Seal between cylinder and engine
pan leaking/damaged (cracks)
Seal or replace engine pan
Decompression lever sticking
Install new cam gear
Piston rings worn or broken
Install new piston rings
Muffler / spark arresting screen (if
fitted) carbonized
Clean muffler (inlet and
exhaust openings), replace
spark arresting screen
(if fitted)
Secondary air seepage through
faulty flange or manifold
Replace faulty parts
Air filter element dirty
Fit new air filter element
Fuel / impulse line kinked or
cracked
Fit new lines or position
without kinks
Pump diaphragm torn
Install new pump diaphragm
Decompression lever sticking
Install new cam gear
Engine pan defective (cracks)
Replace engine pan
Engine does not deliver full power
or runs erratically
10
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BR 500, BR 550, BR 600
If the action of the starter rope
becomes very stiff and the rope
rewinds very slowly or not
completely, it can be assumed that
the starter mechanism is in order
but plugged with dirt. At very low
outside temperatures the lubricating
oil on the rewind spring may thicken
and cause the spring windings to
stick together. This has a
detrimental effect on the function of
the starter mechanism. In such a
case it is sufficient to apply a few
drops of a standard solvent-based
degreasant (containing no
chlorinated or halogenated
hydrocarbons) to the rewind spring.
5.2
Removing and Installing
5.3
Pawl
1
1
: Take out the screws (arrows).
: Remove the starter cover with
rewind starter (1).
2
452RA004 VA
Rewind Starter / Shroud
General
452RA000 VA
5.
5.1
– Remove the starter cover with
rewind starter, b 5.2
: Ease the spring clip (1) off the
starter post starter post.
Install in the reverse sequence.
Carefully pull out the starter rope
several times and allow it to rewind
until its normal smooth action is
restored.
If clogged with dirt or pitch, the
entire starter mechanism, including
the rewind spring, must be removed
and disassembled. Take particular
care when removing the spring.
: Pull the pawls (2) out of the rope
rotor.
Install in the reverse sequence.
– Lubricate pegs on pawls with
grease, b 13.
Lubricate the rewind spring and
starter post with STIHL special
lubricant, b 13, before installing.
BR 500, BR 550, BR 600
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11
5.4
Rope Rotor
– Troubleshooting, b 4.1
Install in the reverse sequence.
Relieving tension of rewind
spring
1
2
– Pull out the starter rope about
5 cm and hold the rope rotor
steady.
452RA001 VA
The rewind spring will not be under
tension if the starter rope is broken.
– While still holding the rotor
steady, take three turns of the
rope off the rotor.
: Fit the washer and the pawls and
engage the spring clip (1) in the
groove on the starter post (2).
– Pull out the starter rope and then
slowly let go of the rotor.
: Make sure the spring clip (1)
engages the guide pegs (arrows)
on the pawls and points them
counterclockwise
– Remove the pawls, b 5.3
1
Handle the spring clip with care.
The rewind starter may not function
properly if the spring clip is
deformed.
2
452RA003 VA
– Tension the rewind spring, b 5.8
Install all other parts in the reverse
sequence.
– Coat the bore in the rope rotor
with STIHL special lubricant,
b 13.
: Fit the rope rotor on the starter
post so that the driver (1) on the
rotor slips behind in the inner
spring loop (2).
Install all other parts in the reverse
sequence.
452RA002 VA
1
2
: Remove the washer (1).
: Carefully remove the rope rotor
(2) from the starter post
– Remove worn or broken starter
rope, b 5.5
12
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BR 500, BR 550, BR 600
5.5
Starter Rope/Grip
– Remove the starter cover with
rewind starter, b 5.2
– Remove the rope rotor, b 5.4
452RA007 VA
452RA006 VA
– Remove the remaining rope from
the rope rotor and starter grip.
– Inspect rope guide bushing in the
starter cover for damage and
replace if necessary, b 5.6
: Pull the rope back into the rotor
so that the knot locates in the
recess (arrow).
: Thread the starter rope through
the bushing in the starter cover
from outside.
– Tension the rewind spring, b 5.8
982RA036 VA
Install all other parts in the reverse
sequence.
452RA005 VA
212RA307 VA
: Tie one of the special knots
shown in the end of the new
starter rope.
: Thread the new rope through the
top of the starter grip from above.
: Thread the rope through the rope
rotor.
– Pull the rope with knot into the
starter grip.
– Tie a simple overhand knot in the
end of the rope.
BR 500, BR 550, BR 600
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13
5.6
Rope Guide Bushing
5.7
Replacing the Rewind
Spring
– Troubleshooting, b 4.1
Wear on the guide bushing is
accelerated by the starter rope
being pulled sideways. The wall of
the guide bushing eventually wears
through and the bushing becomes
loose.
Wear face protection and gloves.
1
452RA009 VA
– Remove the starter cover with
rewind starter, b 5.2
– Remove the rope rotor, b 5.4
– Remove the rope rotor, b 5.4
– Use a suitable tool to pry the
damaged bushing out of the
starter cover.
– Fit the thrust sleeve (1), tapered
end first, and screw on the hex
nut.
: Tighten down the hex nut until the
bushing is firmly seated.
The installing tool flares the lower
end of the rope bushing.
1
1
– Remove the installing tool.
Install all other parts in the reverse
sequence.
– Place the new bushing in its seat
in the starter cover.
: Insert the screw spindle (1) of
installing tool 0000 890 2201
through the bushing from inside
the cover.
452RA010 VA
452RA008 VA
2
: Use a suitable tool to carefully
remove the rewind spring (1)
from the starter cover (2).
– Remove any pieces of broken
spring from the starter cover,
: With the spring housing facing
you, carefully clip the new rewind
spring into the starter cover,
making sure it is correctly
positioned (arrow).
Install in the reverse sequence.
If the rewind spring pops out and
uncoils during installation, refit it in
special tool 1116 893 4800 as
follows:
14
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BR 500, BR 550, BR 600
5.8
Tensioning the Rewind
Spring
1
a
: Position the outer spring loop at
distance “a” (30 mm) from the
edge of the special tool (1).
452RA014 VA
452RA013 VA
452RA011 VA
1
: Place the special tool (1) with the
rewind spring on the spring
housing.
– Remove the starter cover with
rewind starter, b 5.2
: Make a loop in the starter rope.
The outer spring loop must line up
with the recess in the spring
housing (arrow).
– Install the rope rotor, b 5.4
: Wind the rewind spring
counterclockwise, from the
outside inwards.
– To simplify this operation, place
the assembly block
1108 893 4800 across the top of
the special tool.
BR 500, BR 550, BR 600
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452RA168 KN
452RA012 VA
Install all other parts in the reverse
sequence.
: Engage the rope in the notch
(arrow) in the rotor. Grip the rope
close to the rotor and use it to
turn the rotor six full turns
counterclockwise.
15
Shroud
When the starter rope is fully
extended, it must still be possible to
rotate the rope rotor at least another
half turn before maximum spring
tension is reached. If this is not the
case, pull the rope out, hold the
rope rotor steady and take off one
turn of the rope.
Do not overtension the rewind
spring as this will cause it to break.
452RA024 VA
452RA016 VA
5.9
Install in the reverse sequence.
– Remove the starter cover with
rewind starter, b 5.2
: Hold the rope rotor steady.
: Pull out the rope with the starter
grip and straighten it out.
: Take out the screws (arrows)
– Hold the starter grip firmly to keep
the rope tensioned.
452RA161 VA
– Let go of the rope rotor and
slowly release the starter grip so
that the rope winds itself onto the
rotor.
452RA160 VA
: Lay the unit on its back.
The starter grip must sit firmly in the
rope guide bushing without
drooping to one side. If this is not
the case, tension the spring by one
additional turn.
16
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BR 500, BR 550, BR 600
6.
6.1
3
Fuel System
Air Filter
Dirty air filters reduce engine power,
increase fuel consumption and
make starting more difficult.
3
2
1
: Take out the screws (1).
: Ease the engine in the direction
of the backplate until the stop
buffers (3) are clear of their seats
(arrows) and pull the shroud (2)
towards you at the same
time.rauskommen.
452RA157 VA
1
452RA025 VA
The air filter must be replaced when
there is a noticeable loss of engine
power.
1
– Coat new stop buffers (1) with
STIHL Press Fluid OH 723,
b 13.
– Use pliers to grip end of stop
buffer and pull it up until its
groove (arrow) engages the
housing.
Install in the reverse sequence.
452RA026 VA
1
: Loosen the screws (arrows).
: Lift away the filter cover (1).
BR 500 only
1
1
– Remove the stop buffers (1).
– If the shroud is replaced, also
bond a soundproofing liner (1) in
position.
Install all other parts in the reverse
sequence.
BR 500, BR 550, BR 600
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452RA027 VA
452RA095 VA
1
452RA156 VA
1
: Remove the air filter (1).
The filter element cannot be
washed and must be replaced if it is
heavily loaded.
17
452RA030 VA
452RA028 VA
– If the filter housing has to be
replaced, remove the shroud and
rewind starter, b 5.9
2
452RA032 VA
1
1
2
: Pull off the carburetor (1).
: Carefully pull out the hose (1).
: If necessary, remove the baffle
(2).
: Carefully disconnect the hose (2)
and pull it out of the housing bore
(arrow).
: Take out the screws (arrows)
When installing, always fit a new
gasket between the carburetor and
filter housing.
452RA029 VA
452RA033 VA
1
: Take out the screw (arrow).
: Squeeze the tabs (arrows)
together and disengage the fuel
pump (1).
2
1
1
1
: Pull the filter housing (1) off its
mounting (arrow).
452RA034 VA
452RA031 VA
452RA035 VA
1
: Carefully remove the hoses (1).
: Pry the grommet (1) out to the
rear.
: Pull out the throttle cable (2).
– Take the filter housing (1) out of
the machine.
Install in the reverse sequence.
Replace damaged hoses.
18
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BR 500, BR 550, BR 600
6.2
6.2.1
Carburetor
Leakage Test
– Troubleshooting, b 4.3
1
2
The carburetor can be tested for
leaks with the carburetor and
crankcase tester 1106 850 2905.
452RA038 VA
452RA051 VA
In the event of trouble with the
carburetor or fuel supply system,
always check, clean or replace the
tank vent, b 6.5
– Remove the air filter, b 6.1
Use a new grommet.
– Close the tank filler cap.
1
452RA037 VA
1
452RA036 VA
1
: Clip the fuel pump in place so that
the longer stub (1) is at the
bottom.
: Disconnect the fuel hose (1) from
the carburetor.
2
: Push the hose (2) with nipple (1)
onto the carburetor’s elbow
connector.
2
452RA162 VA
: Push the grommet into the filter
housing from the rear until its
groove (arrow) engages the
housing.
– Open the tank filler cap to relieve
pressure.
: Connect hose (1) of tester
1106 850 2905 to the nipple (2).
: Pass the hose (2) that comes
from the tank through the housing
bore (arrow) and push it onto the
long stub (1).
Install all other parts in the reverse
sequence.
2
1
143RA172 VA
– Check tension of throttle cable,
adjust if necessary, b 9.3.2
: Push the hose (1) 1110 141 8600
onto the nipple (2)
0000 855 9200.
BR 500, BR 550, BR 600
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19
6.2.2
3
Removing and Installing
6.3
6.3.1
Servicing the Carburetor
Metering Diaphragm
1
2
2
: Close the vent screw (1) on the
rubber bulb (2) and pump air into
the carburetor until the pressure
gauge (3) shows a reading of
about 0.8 bar (80 kPa).
452RA041 VA
452RA039 VA
1
249RA012 VA
1
– Remove the filter housing, b 6.1
– Remove the carburetor, b 6.2.2
: Disconnect the fuel hose (1).
: Take out the screws (arrows).
: Disconnect the impulse hose (2).
: Remove the end cover (1).
If this pressure remains constant,
the carburetor is airtight. However, if
it drops, there are two possible
causes:
2
1
: Disconnect nipple (1) from the
slotted pin (2) on the throttle
lever.
– Push the fuel hose onto the
elbow connector.
– Check flange for damage and
replace if necessary.
– Install the carburetor, b 6.2.2
Install in the reverse sequence.
Install all other parts in the reverse
sequence.
Always install new gaskets.
: Remove the metering diaphragm
and gasket (arrow) from the
carburetor body or end cover.
176RA272 VA
– After completing the test, open
the vent screw (1) and pull the
hose off the carburetor.
452RA040 VA
2. Metering diaphragm is damaged,
replace if necessary, b 6.3.1
452RA042 VA
1. Inlet needle is not sealing foreign
matter in valve seat or sealing cone
of inlet needle is damaged or inlet
control lever sticking), remove to
clean, b 6.3.2
Carefully separate the diaphragm
and gasket.
If the gasket and diaphragm are
stuck to the carburetor, remove and
separate them very carefully.
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BR 500, BR 550, BR 600
6.3.2
As a result of the alternating
stresses, the diaphragm material
and the inlet and outlet valves
eventually show signs of fatigue, i.e.
the diaphragm distorts and swells
and has to be replaced.
Inlet Needle
2
1
3
Use a new gasket.
: Line up the hole in the metering
diaphragm (1) with the bore in the
carburetor body.
1
452RA046 VA
452RA044 VA
Install in the reverse sequence.
– Remove the metering
diaphragm, b 6.3.1
: Take out the screw (1).
: Remove the inlet control lever (2)
with spindle.
1
There is a small spring (arrow)
under the inlet control lever. It may
pop out during disassembly.
1
: Place the gasket (1) on the
carburetor body so that the hole
in the gasket lines up with the
bore in the carburetor body
(arrows).
452RA045 VA
452RA043 VA
– Pull out the inlet needle (3).
: Place the end cover (1) in
position.
Make sure the bore in the end cover
lines up with the hole in the
metering diaphragm (arrows).
– Fit the screws and tighten them
down firmly, b 3.4
Install all other parts in the reverse
sequence.
2
1
452RA159 VA
212RA281 VA
3
: Place the metering diaphragm (1)
on the carburetor body so that the
perforated sheet (2) faces the
inlet control lever (3).
: If there is an annular indentation
(arrow) on the sealing cone of the
inlet needle, replace the inlet
needle because it will no longer
seal properly.
BR 500, BR 550, BR 600
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21
6.3.3
Pump Diaphragm
4
– Carefully separate the diaphragm
and gasket.
1
3
– Inspect the diaphragm for
damage and wear, fit a new
gasket.
452RA048 VA
2
452RA047 VA
1
Install in the reverse sequence.
– Remove the carburetor, b 6.2.2
: Fit the inlet needle (1).
: Take out the screws (arrows)
: Place the helical spring (2) in the
bore.
: Remove the end cover (1).
: Insert the spindle (3) in the inlet
control levers (4).
1
1
– Engage clevis in annular groove
on head of the inlet needle.
– Check that the inlet control lever
moves freely.
2
: Remove the spring (1).
452RA052 VA
Make sure the helical spring locates
on the control lever’s nipple.
452RA049 VA
– Push the inlet control lever down
and secure in position with the
screw.
: Remove the pump cover (1).
: Remove the washer (2).
The upper edge of the inlet control
lever must be flush with the top of
the carburetor body.
– Install the metering diaphragm,
b 6.3.1
2
1
2
1
452RA050 VA
452RA053 VA
Install all other parts in the reverse
sequence.
: Remove the gasket (1) with pump
diaphragm (2).
: Remove the gasket (1) with pump
diaphragm (2).
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BR 500, BR 550, BR 600
6.3.4
– Carefully separate the diaphragm
and gasket.
1
Accelerator Pump
2
– Inspect the diaphragm for
damage and wear, fit anew
gasket.
452RA056 VA
As a result of the alternating
stresses, the diaphragm material
and the inlet and outlet valves
eventually show signs of fatigue, i.e.
the diaphragm distorts and swells
and has to be replaced.
452RA055 VA
2
1
: Fit the diaphragm (1) and
gasket (2) on the carburetor body
so that contours (arrow) match.
– Remove the carburetor, b 6.2.2
– Place the end cover on the
carburetor.
: Take out the screw (1).
Wear safety glasses.
: Remove the throttle lever (2).
The pump diaphragm and gasket
are held in position by cast pegs on
the end cover.
1
– Fit the screw and tighten it down
firmly, b 3.4
: Examine the fuel strainer (1) for
contamination and damage. If
necessary, use a needle to pull it
out of the carburetor body and
clean or replace.
2
1
452RA057 VA
452RA054 VA
Install all other parts in the reverse
sequence.
: Carefully remove the spring (1).
: Remove the sleeve (2).
Install in the reverse sequence.
2
452RA058 VA
1
Note correct installed position of
throttle shutter.
: Take out the screw (1).
: Remove the throttle shutter (2).
BR 500, BR 550, BR 600
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23
– Inspect components for damage
and wear, replace as necessary.
452RA062 VA
1 2
452RA059 VA
Install in the reverse sequence,
always using a new pump piston.
Note the installed position of the
spring (2).
: Check correct installed position
(arrows) of spring.
Always cover the bore (arrow) with
a finger to stop components
popping out.
Install all other parts in the reverse
sequence.
Install the parts of the accelerator
pump in the following sequence:
First fit the spring (2) in the pump
piston (1) and insert them both in
the bore (arrow). Slide the throttle
shaft (4) with spring (3) into the
carburetor body. Use a suitable tool
to carefully hold down the pump
piston and then push the throttle
shaft fully home.
: Check correct installed position
(arrows) of spring.
452RA060 VA
1
2
3
2
452RA063 VA
4 3 1
452RA061 VA
: Carefully pull out the throttle
shaft (1).
: Take the pump piston (1) with
sealing ring (2) and spring (3) out
of the carburetor body.
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BR 500, BR 550, BR 600
6.4
6.4.1
Adjusting the Carburetor
User Adjustment
1
– Use a new screw and coat it with
Loctite.
: Fit the throttle shutter (1) and
tighten it down moderately,
b 3.4
Check that the stamped digits
(arrow) face up.
452RA066 VA
452RA065 VA
452RA064 VA
1
– Check that the notch in the
throttle shutter lines up with the
bores (arrows) in the carburetor
body.
Standard setting
: Loosen the screw (1) slightly.
– Center the throttle shutter so that
it moves freely.
– With this carburetor it is only
possible to correct the setting of
the high speed screw (H) and low
speed screw (L) within fine limits.
: Tighten down the screw (1).
Make the following adjustments:
– Check that shutter still moves
freely.
– Turn the high speed screw (H)
counterclockwise as far as stop.
Install all other parts in the reverse
sequence.
– Turn the low speed screw (L)
counterclockwise as far as stop.
Do not remove the limiter caps to
carry out the standard setting.
– Check the air filter and replace it
if necessary, b 6.1
If the air filter is dirty, install a new
one – do not clean.
– Check adjustment of throttle
cable, b 9.3.2
– Check the spark arresting screen
(if fitted), b 7.6
– Start the engine and allow it to
warm up.
– Adjust engine idle speed.
BR 500, BR 550, BR 600
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25
6.4.2
– Turn the idle speed screw (LA)
slowly clockwise until the engine
runs smoothly.
Erratic idling behavior, engine
stops even though setting of LA
screw is correct, poor
acceleration, idle speed too high
The limiter caps need to be
removed only if it is necessary to
replace the high speed screw (H) or
low speed screw (L), clean the
carburetor or adjust it from scratch.
1
2
After removing the limiter caps it is
necessary to carry out the basic
setting.
452RA068 VA
Engine stops while idling
Basic Setting in
Service Shop
– Idle setting is too lean. Turn the
low speed screw (L) counterclockwise (no further than stop)
until the engine runs and
accelerates smoothly.
After removing the limiter caps it is
necessary to carry out the basic
setting.
Erratic idling behavior
Make the following adjustments:
– Idle setting is too rich. Turn the
low speed screw (L) clockwise
(no further than stop) until the
engine runs and accelerates
smoothly.
– Open the high speed screw H (1)
3 1/2 turns counterclockwise.
– Screw both adjusting screws
down against their seats.
Fine-tuning the carburetor for
operation at high altitude
A minor correction may be
necessary if engine does not run
satisfactorily:
– Check the standard setting.
– Warm up the engine.
– Turn the high speed screw (H)
clockwise (leaner), but no further
than stop.
If the setting is too lean, there is a
risk of engine damage due to
insufficient lubrication and
overheating.
1
2
452RA067 VA
– Open the low speed screw L (2)
2 turns counterclockwise.
– Set the idle speed to 2,500 rpm
with the low speed screw (L).
Fine tuning with tachometer
– Remove the shroud with rewind
starter, b 5.9
– Check the air filter and replace it
if necessary.
: Push the puller (1)
5910 890 4501, with the open
side facing you, between the
limiter cap (2) and carburetor
body and pry the cap off. If the
limiter cap is stuck on the screw,
turn the puller over so that its
open side faces the carburetor
body. Pry off the limiter cap.
If the air filter is dirty, install a new
one – do not clean.
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– Check the spark arresting screen
(if fitted) and clean or replace if
necessary.
– Warm up the engine.
BR 500, BR 550, BR 600
6.5
Adjust the idle speed with a
tachometer. Adjust the specified
engine speeds within a tolerance of
± 200 rpm.
2.
Adjust engine sped with idle
speed screw (LA) to
3,300 rpm.
Turn low speed screw (L)
clockwise or counterclockwise to obtain
maximum engine speed.
If this speed is higher than
3,700 rpm, abort the procedure and
start again with step 1.
3.
Use the idle speed screw
(LA) to set engine speed
Correct operation of the carburetor
is only possible if atmospheric
pressure and internal fuel tank
pressure are equal at all times. This
is ensured by the tank vent.
2
1
452RA069 VA
1.
Tank Vent
Do not re-stall used caps because
they may be damaged. Always
install new limiter caps.
: Place the new limiter caps on the
adjusting screws (1+2) so that
they are positioned against the
rich stop.
In the event of trouble with the
carburetor or the fuel supply
system, always check and clean the
tank vent.
Check function by performing
pressure and vacuum tests on fuel
tank via the fuel hoses.
– Disconnect both hoses from the
carburetor, b 6.2.2
– Seal one of the two hoses with a
suitable plug.
again to 3,300 rpm.
4.
Set the engine speed to
2,500 rpm with the low
speed screw (L).
5.
Use the high speed
screw (H) to adjust the
maximum engine speed to:
5,500 rpm on the BR 500
6,100 rpm on the BR 550
7,200 rpm on the BR 600
– Connect the other hose to the
vacuum pump 0000 850 3501
and test fuel tank under vacuum.
452RA070 VA
a
: Push the caps onto the screws
until dimension “a” is 5 mm.
– Adjust engine idle speed,
b 6.4.1
BR 500, BR 550, BR 600
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27
6.6
Fuel Hoses/Pickup Body
Equalization of pressure takes
place via the tank vent (1). There
must be no build-up of vacuum in
the tank. If the tank vent does not
operate properly, replace it together
with the O-ring.
1
452RA074 VA
452RA072 VA
452RA071 VA
1
– Remove the shroud with rewind
starter, b 5.9
The tab on the connector (arrow)
must locate in the fuel tank’s recess.
: Carefully pry the connector (1)
with hoses and pickup body out
of its seat.
– Press home the connector as far
as stop – it must snap audibly into
position.
– Clean the tank vent (1) and the
area around it before removing.
2
: If the tank vent (1) has to be
replaced, use a suitable tool to
pry it out of the fuel tank.
Take care not to damage the fuel
tank.
Install in the reverse sequence.
Use a new O-ring.
– Coat O-ring and bead of tank
vent with
STIHL Press Fluid OH 723
before installing, b 13.
1
452RA073 VA
Hold the tank vent during this
operation to prevent it popping out.
: If necessary, pull off the fuel
hoses (arrows) and pickup
body (1).
Install in the reverse sequence.
: Fit a new O-ring (2).
– Press home the tank vent
squarely as far as stop – it must
snap audibly into position.
Install all other parts in the reverse
sequence.
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BR 500, BR 550, BR 600
6.7
Fuel Tank
7.
7.1
Engine
Compression Pressure
1
3
2
– Drain the fuel tank.
– Pull off the spark plug boot.
– Remove the tank vent, b 6.5
– Unscrew the spark plug.
– Remove the fuel hoses, b 6.6
: Screw compression tester
5910 850 2000 (1) into the spark
plug hole.
: Take the screws (arrows) out of
the bottom of the backplate.
452RA153 VA
452RA077 VA
452RA075 VA
1
: Connect spark plug boot to
terminal (1).
: Attach the ground terminal (2) to
the muffler.
: Set the spark gap to about 2 mm
with the adjusting knob (3).
The ZAT 3 ignition system tester
5910 850 4520 must be fitted to
discharge the ignition voltage.
– Remove the fuel tank.
The high voltages that occur can
cause an electric shock.
1
452RA076 VA
2
: Disconnect the tank cap cord (1)
from the slot (2).
– Remove the fuel tank cap.
Install in the reverse sequence.
BR 500, BR 550, BR 600
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29
7.2
Checking / Adjusting
Valve Clearances
1
1
2
When using the ZAT 3, hold it only
by the handle (4) or position it in a
safe place. Keep fingers or other
parts of body at least 1 cm away
from the spark window (3), the high
voltage connection (2), ground
connection (5) and the ground
terminal (1).
– Crank the engine quickly with the
starter (min. 1,000 rpm).
–
– Note compression pressure.
Check and adjust valve clearances
only when engine is cold.
– Remove the shroud with rewind
starter, b 5.9
: Disconnect wires (1) and (2) from
the ignition module.
: Take the wires out of the air guide
shroud (arrow).
3
452RA080 VA
452RA078 VA
2
: Take out the screw (1).
– Remove the sealing ring (arrow).
–
– Remove the valve cover (2) with
gasket.
– Use combination wrench
4180 890 3400 to unscrew the
spark plug.
If compression pressure is below
7.5 bar, check valve clearance and
readjust if necessary, b 7.2.
If this produces no improvement,
check the cylinder, valve seat,
piston and piston rings for scores
or other damage and replace if
necessary.
The design specification is 7.5 –
8.5 bar.
: Take out the screws (arrows)
: Remove the air guide shroud (1).
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452RA081 VA
1
452RA079 VA
If a much higher reading is obtained
(9 – 10 bar), check operation of the
decompression system and replace
if necessary, b 7.5.1.
– Rotate the crankshaft until the tip
(arrow) of the flywheel lines up
with the ignition module as
shown.
BR 500, BR 550, BR 600
7.3
Rocker Arms / Pushrods
– Remove the inner fan housing,
b 11.2
Observe rocker arms while rotating
the fanwheel. If the valves are
operated by the rocker arms in this
position (valve overlap), rotate the
crankshaft another turn until the
valves are idle (ignition TDC). Turn
the crankshaft back and forth a little
to check again that the valves are
not operated in this position.
– Take out the locking screw
4282 890 2700.
452RA083 VA
– Remove the valve cover, b 7.2
– Set the piston to ignition TDC,
b 7.2
Adjusting valves
Valve clearance is adjusted with the
locknuts (arrows).
To increase valve clearance:
Loosen the nut.
1
To reduce valve clearance:
Tighten the nut.
3
1
: Insert feeler gauge
4180 893 6400 (1) between
rocker arm and valve stem.
Assemble all parts in the reverse
sequence.
452RA101 VA
2
452RA082 VA
– Turn engine over several times,
check valve clearance again and
adjust if necessary.
– Thoroughly clean the sealing
faces on the cylinder and cover.
: Remove the locknut (1).
Fit a new gasket.
The feeler gauge must slip through
with a certain resistance.
Inlet valve (2) = 0.10 ± 0.02 mm
Exhaust valve (3) = 0.10 ± 0.02 mm
452RA102 VA
1
: Remove the sleeve (1).
BR 500, BR 550, BR 600
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31
7.4
Cam Followers
452RA103 VA
1
: Remove the rocker arm (1).
Install in the reverse sequence.
– Remove the pushrods, b 7.3
Cam lobe on cam gear must point
downward.
: Pull out the pin (1).
Coat all parts with two-stroke
engine oil before installing.
: Remove the cam followers (2)
and (3).
Install in the reverse sequence.
Make sure the pushrod is properly
seated in the rocker arm and cam
follower.
1
– Adjust the valves, b 7.2
Coat all parts with two-stroke
engine oil before installing.
Install the left-hand cam follower
first. It controls the inlet valve.
452RA104 VA
– Thoroughly clean the sealing
faces on the cylinder and cover.
– Apply thin coating of sealant to
cylinder sealing face, b 13.
Follow maker's instructions.
: Take out the pushrod (1).
1
2
452RA099 VA
1
: Take out the screws (1).
: Carefully pry off the cover (2) in a
crosswise pattern at the points
shown (arrows).
32
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BR 500, BR 550, BR 600
Cam Gear
7.5.1
2
3
4
452RA167 VA
1
Decompression System
249RA140 VA
7.5
– Remove the cam followers,
b 7.4
: Fit the cam gear so that the
marks (2) and (3) and in
alignment with the notches (1)
and (4) in the cylinder.
: Pull out the pin (1).
– Remove cam gear cover, b 7.3
: Check free movement and
function of decompression
system lever (arrow).
: Remove the cam gear (2).
– Lever must project about 2 mm
from the cam.
Install in the reverse sequence.
1
Coat all parts with two-stroke
engine oil before installing.
– Push decompression system
lever counterclockwise. The lever
must move freely and retract fully.
452RA107 VA
If the lever is difficult to move, worn
or not visible, install a new cam
gear, b 7.5.
: Install the pin (1).
The marks must not move out of
position while the cam gear is being
fitted.
– Rotate the crankshaft until the
cam lobe on the cam gear points
downward.
452RA081 VA
– Install the cam followers, b 7.4
: Rotate the crankshaft until the tip
(arrow) of the flywheel lines up
with the ignition module as
shown.
BR 500, BR 550, BR 600
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33
7.6
Muffler/Spark Arresting
Screen
1
452RA020 VA
452RA018 VA
2
2
: Loosen the screws (1).
: Remove the gasket (1).
: Push the scoop (1) into place.
: Remove the scoop (2) to the left.
– Clean the sealing faces.
: Tighten down the screws (2)
firmly.
452RA022 VA
2
1
1
Install in the reverse sequence.
Always install a new muffler gasket.
Install all other parts in the reverse
sequence.
452RA023 VA
1
: If a spark arresting screen (1) is
fitted, carefully pry it out and
clean or replace it as necessary.
1
452RA019 VA
452RA021 VA
1
: Take out the screws (arrows)
: Carefully fit the spark arresting
screen (1) in position.
: Remove the muffler (1).
Guide lug on spark arresting screen
must engage the scoop.
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BR 500, BR 550, BR 600
7.7
Flywheel
7.8
– Lift away the flywheel.
If the flywheel or magnet poles are
damaged or have turned blue,
install a new flywheel.
452RA108 VA
1
– Remove the shroud with rewind
starter, b 5.9
– Clean the stub of the crankshaft
and the flywheel hub bore with a
standard commercial, solventbased degreasant containing no
chlorinated or halogenated
hydrocarbons, b 13.
Install in the reverse sequence.
Testing for Leaks
Defective oil seals and gaskets or
cracks in castings are the usual
causes of leaks. Such faults allow
supplementary air to enter the
engine and upset the fuel-air
mixture.
This makes adjustment of the
prescribed idle speed difficult, if not
impossible.
Moreover, the transition from idle
speed to part or full throttle is not
smooth.
The crankcase can be checked
thoroughly for leaks with the
carburetor and crankcase tester
and the vacuum pump.
– Unscrew the spark plug and
install the locking screw
4282 890 2700 in its place.
Always use the specified locking
screw. Other locking screws may
damage the piston.
Always carry out the vacuum test
first and then the pressure test.
After completing the tests, always
install a new muffler gasket.
452RA138 VA
: Unscrew the flywheel nut (1).
: Make sure the flywheel’s
key (arrow) engages the slot in
the crankshaft.
– Adjust gap between ignition
module and flywheel, b 8.4
Install all other parts in the reverse
sequence.
2
452RA109 VA
1
: Screw home the puller
1116 893 0800 (1).
– Tap the puller until the flywheel
(2) is released from its seat.
BR 500, BR 550, BR 600
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35
7.8.1
Preparations
7.8.2
The sealing plate must completely
fill the space between the screws.
2
– Set the piston to top dead center.
Vacuum Test
Oil seals tend to fail when subjected
to a vacuum, i.e. the sealing lip lifts
away from the crankshaft during the
piston's induction stroke because
there is no internal counterpressure.
– Perform vacuum test, b 7.8.2
1
452RA110 VA
– Perform pressure test, b 7.8.3
A test can be carried out with the
vacuum pump to detect this kind of
fault.
– Remove the carburetor, b 6.2.2
– Loosen the muffler mounting
screws, b 7.6
: Seal the impulse hose (1) with a
suitable plug.
452RA112 VA
: Mount the test flange
1119 850 4201 (2) to the
manifold with suitable screws.
1
– Carry out the preparations,
b 7.8.1
: Connect suction hose (1) of
vacuum pump 0000 850 3501 to
nipple (arrow) of the test flange.
3
: Slide the sealing plate
0000 855 8106 (1) between the
muffler and cylinder exhaust port.
– Tighten the muffler mounting
screws moderately.
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1
2
452RA113 VA
452RA111 VA
1
: Close the vent screw (1) on the
pump.
: Operate the lever (2) until the
pressure gauge (3) indicates a
vacuum of 0.5 bar.
BR 500, BR 550, BR 600
7.8.3
Pressure Test
– After finishing the test, open the
vent screw and disconnect the
hose.
– Carry out pressure test, b 7.8.3
If this pressure remains constant for
at least 20 seconds, the crankcase
is airtight. If the pressure drops, the
leak must be found and the faulty
part replaced.
452RA112 VA
If the vacuum reading remains
constant, or rises to no more than
0.3 bar within 20 seconds, it can be
assumed that the oil seals are in
good condition.
However, if the pressure continues
to rise (reduced vacuum in the
crankcase), the oil seals must be
replaced.
1
– Always carry out the vacuum test,
b 7.8.2, before this pressure
test.
: Connect pressure hose (1) of
tester 1106 850 2905 to nipple
(arrow) on test flange.
– To find the leak, coat the suspect
area with oil and pressurize the
crankcase again. Bubbles will
appear if a leak exists.
– If necessary, repeat the pressure
test.
– After finishing the test, open the
vent screw and disconnect the
hose.
– Remove the test flange.
– Remove the sealing plate.
Install in the reverse sequence.
– After completing the tests, always
install a new muffler gasket,
b 7.6
2
1
249RA012 VA
3
: Close the vent screw (1) on the
rubber bulb.
: Pump air into the crankcase with
rubber bulb (2) until the gauge (3)
indicates a pressure of 0.5 bar.
BR 500, BR 550, BR 600
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37
7.9
7.9.1
Crankshaft
Oil Seals
It is not necessary to disassemble
the engine to replace the oil seals.
1
Starter side
– Remove the flywheel, b 7.7
1
– Thinly coat the outside diameter
of the oil seal with sealant, b 13.
452RA117 VA
452RA115 VA
– Free off the oil seal in its seat by
tapping it with a suitable tube or a
punch.
Fanwheel side
– Remove the fanwheel, b 11.3
– Lubricate sealing lips of oil seal
with grease, b 13.
: Apply puller (1) 5910 890 4400
with No. 3.1 jaws and clamp the
arms.
– Slip the oil seal (1) over the
crankshaft and up against the
crankcase.
– Pull out the oil seal.
Note installed position:
Closed side of oil seal must face
outward.
Take care not to damage the
crankshaft stub.
– Inspect the crankshaft running
face for scores.
452RA114 VA
1
– Clean sealing face in crankcase
with standard solvent-based
degreasant containing no
chlorinated or halogenated
hydrocarbons,
b 13.
: Apply puller (1) 5910 890 4400
with No. 3.1 jaws and clamp the
arms.
Install in the reverse sequence.
– Pull out the oil seal.
Take care not to damage the
crankshaft stub.
2
1
452RA118 VA
– Clean sealing face in crankcase
and crankshaft with standard
solvent-based degreasant
containing no chlorinated or
halogenated hydrocarbons,
b 13.
452RA116 VA
1
– Inspect the crankshaft running
face for scores.
Install in the reverse sequence.
: Use the press sleeve (2)
1108 893 2405 to press home the
oil seal (1) until it is flush with the
crankcase.
: Slip the installing sleeve (1)
1118 893 4602 over the end of
the crankshaft.
Install all other parts in the reverse
sequence.
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BR 500, BR 550, BR 600
Crankcase, Lower Half
452RA119 VA
1
1
452RA121 VA
1
– Thinly coat the outside diameter
of the oil seal with sealant, b 13.
– Remove the inner fan housing,
b 11.2
– Slip the oil seal (1) over the
crankshaft and up against the
crankcase.
: Take out the screws (arrows).
: Fit the engine pan (1) in position.
: Tighten down the screws
(arrows) in a crosswise pattern.
Observe sequence and
tightening torque, b 3.4
: Lift away the engine pan (1).
Note installed position:
Closed side of oil seal must face
outward.
452RA121 VA
7.9.2
Install all other parts in the reverse
sequence.
1
452RA122 VA
1
: Clean the sealing faces (arrows)
on the cylinder and engine pan
with standard solvent-based
degreasant containing no
chlorinated or halogenated
hydrocarbons, b 13.
Do not take the crankshaft out of the
bearings because this will alter cam
gear timing, b 7.5.
: Check condition of oil seals (1)
and replace if damaged.
2
452RA169 KN
Install in the reverse sequence.
– Apply thin coating of sealant to
cylinder and engine pan sealing
faces, b 13.
: Use the press sleeve (1)
1108 893 2405 (2) to press home
the oil seal until it is flush with the
crankcase.
Install all other parts in the reverse
sequence.
BR 500, BR 550, BR 600
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39
Crankshaft
7.9.4
Always check and, if necessary,
repair the fuel system, carburetor,
air filter and ignition system before
looking for faults on the engine. See
also “Troubleshooting”, b 4.
3
2
– Remove the lower half of the
crankcase, b 7.9.2
1
: Examine ball bearings (1),
connecting rod (2) and gear (3).
– If one of these parts is damaged,
install a new crankshaft
assembly.
Install in the reverse sequence.
2
1
249RA088 VA
1
3
Piston
249RA087 VA
7.9.3
– Remove the crankshaft, b 7.9
Always wear safety glasses when
working with spring washers and
snap rings.
: Use a suitable tool to ease the
hookless snap ring out of the
groove.
– Coat piston and piston rings with
oil.
249RA086 VA
– Fit piston rings so that their gaps
are offset 120 degrees.
: Lift the crankshaft (1) and pull the
piston out of the cylinder at the
same time.
– Use new oil seals.
– Lubricate sealing lips of oil seals
with grease, b 13.
– Apply thin coating of sealant to
outer diameter of oil seals, b 13.
– Carefully fit piston in the cylinder.
: Pull off the oil seals (2 and 3).
– Inspect cylinder running face for
signs of damage and serious
scores. Install new cylinder with
piston if necessary, b 7.9.7
– Install the crankshaft with new oil
seals in the cylinder.
– Fit lower half of crankcase,
b 7.9.2
1
2
Install all other parts in the reverse
sequence.
249RA089 VA
– Align the flywheel and fit the cam
gear, b 7.5
: Use the assembly drift (2)
1110 893 4700 to push the piston
pin (1) out of the piston.
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BR 500, BR 550, BR 600
: Use the assembly drift
1108 893 4700 to push the piston
pin through the piston and
connecting rod.
2
1
249RA145 VA
249RA092 VA
If the piston pin is stuck, tap the end
of the drift lightly with a hammer if
necessary. Hold the piston steady to
ensure that no jolts are transmitted
to the connecting rod.
: Attach the snap ring (1) to the
magnet (2) so that the snap ring
gap is on the flat side of the tool’s
shank.
452RA163 VA
249RA146 VA
1
452RA123 VA
2
: Inspect piston rings and replace if
necessary, b 7.9.5
Use installing tool 5910 890 2212
with sleeve 5910 893 1704 to fit the
snap ring, b 12.
: Push the large slotted diameter of
the sleeve over the magnet and
snap ring. Position the sleeve so
that the inner pin (1) points
towards the flat face (2) of the
tool’s shank.
Install in the reverse sequence.
452RA124 VA
: Remove the sleeve from the tool.
: The arrow stamped in the piston
crown (arrow) points towards the
exhaust port.
BR 500, BR 550, BR 600
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41
: Stand the installing tool, sleeve
downward, on a flat surface
(wooden board) and press
vertically downwards until the
sleeve butts against the tool’s
shoulder.
Piston Rings
: Apply the installing tool to the
piston boss, hold the piston
steady, center the tool shank
exactly and press home until the
snap ring slips into the groove.
452RA123 VA
249RA149 VA
249RA147 VA
7.9.5
– Remove the piston, b 7.9.4
– Remove rings from piston.
– Use a piece of old piston ring to
scrape the grooves (arrows)
clean.
– Install new piston rings.
– Check that piston ring gaps are
offset 120 degrees.
249RA148 VA
Install in the reverse sequence.
: Remove the sleeve and slip it
onto the other end of the shank.
249RA150 VA
Inner pin must point towards flat
face.
Fit the snap ring so that its gap is on
the piston’s vertical axis (it must
point either up or down).
Install all other parts in the reverse
sequence.
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BR 500, BR 550, BR 600
7.9.6
Valves / Valve Springs
7.9.7
452RA125 VA
1
2
Upper Half of Crankcase
with Cylinder
– Inspect valve seats in cylinder
head for any damage. Replace
cylinder if necessary.
If the cylinder with piston has to be
replaced, first carry out the following
operations:
Install in the reverse sequence.
– Remove the muffler, b 7.6
Valve spring retainer must engage
properly in groove of valve stem.
– Remove the crankshaft, b 7.9.3
– Remove the rocker arms/
pushrods, b 7.3
– Remove the cam gear, b 7.5
– Remover rocker arms/pushrods,
b 7.3
– Remove the ignition module,
b 8.4
– Remove the crankshaft, b 7.9.3
Do not mix up the large inlet valve
and the small exhaust valve.
– Use combination wrench
4180 890 3400 to unscrew the
spark plug, check it for wear and
replace if necessary.
: Press valve spring retainer (1)
down and move it sideways so
that the valve stem is in the large
hole.
: Remove the spring retainer (1)
and together with the valve
spring (2).
– Take the valves out of the
cylinder.
1
2
3
1
2
3
452RA127 VA
3
452RA126 VA
4
: Check valve heads (1 and 2) for
damage.
: Loosen the clamp (3) and remove
the manifold (2) with flange (1).
: Check valve springs (3) for
damage.
: Pull off the impulse hose (4).
BR 500, BR 550, BR 600
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43
8.
– Fit the carburetor, line up the
flange and manifold so it is
straight and then secure the
clamp.
1
2
3
452RA128 VA
– Carefully tighten down the clamp
until the distance between the
tabs is 5–6 mm.
Ignition System
Exercise extreme caution when
carrying out maintenance and repair
work on the ignition system. The
high voltages which occur can
cause serious or even fatal
accidents.Troubleshooting on the
ignition system should always begin
at the spark plug, b 4.2.
Use new gaskets.
Install all other parts in the reverse
sequence.
: Remove the sleeve (1).
: Check flange (2) and manifold (3)
for damage and replace if
necessary.
: If necessary, pull the flange (2) off
the manifold (3).
Install in the reverse sequence.
: When installing, check that the
notches (arrows) in the manifold
line up with the screw sleeves in
the flange.
1
2
452RA129 VA
: Make sure the sleeve (1) is
properly seated.
452RA098 VA
The solid state (breakerless)
ignition system basically consists
of an ignition module (1) and
flywheel (2).
: When installing, check that the
groove in the manifold is properly
seated in the fan housing (arrow).
44
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BR 500, BR 550, BR 600
8.1
Ignition Module
1
8.2
3
2
Ignition Timing
Ignition timing is fixed and cannot
be adjusted during repair or
servicing work.
Testing the Ignition
Module
To test the ignition module, use
either the ZAT 4 ignition system
tester 5910 850 4503 or the ZAT 3
ignition system tester
5910 850 4520.
The ignition test refers only to a
spark test, not to ignition timing.
452RA130 VA
Since there is no mechanical wear
in these systems, ignition timing
cannot get out of adjustment.
8.3
The ignition module accommodates
all the components required to
control ignition timing. There are
three electrical connections on the
coil body:
: High voltage output (3) for the
ignition lead
: Connector tag (2) for the short
circuit wire
Testing the ignition module in the
workshop is limited to a spark test.
A new ignition module must be
installed if no ignition spark is
obtained (after checking that wiring
and stop switch are in good
condition).
1
2
3
212RA209 VA
: Screw-mounted connector
tag (1) for the ground wire
Using the ZAT 4 ignition tester
5910 850 4503
– Before starting the test, install a
new spark plug in the cylinder
and tighten it down firmly, b 3.4
: Pull the boot off the spark plug
and connect it to the input
terminal (1). Push the tester’s
output terminal (3) onto the spark
plug.
: Crank the engine quickly with the
rewind starter (min. 1,000 rpm)
and check spark in the tester’s
window (2).
Warning!
The engine may start and
accelerate during the test.
BR 500, BR 550, BR 600
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45
8.4
If a spark is visible, the ignition
system is in order. If no spark is
visible in the window (2), check the
ignition system with the aid of the
troubleshooting chart, b 8.7.
Removing and Installing
1
3
4
When using the ZAT 3, hold it only
by the handle (4) or position it in a
safe place. Keep fingers and other
parts of body at least 1 cm away
from the spark window (3), the high
voltage connection (2), ground
connection (5) and the ground
terminal (1).
The high voltages that occur can
cause an electric shock.
– Crank the engine quickly with the
rewind starter (min. 1,000 rpm)
and check spark in the tester’s
window (3).
ZAT 3
2
3
4
212RA235 VA
5910 850 4520
1
Using ZAT 3 ignition system
tester 5910 850 4520
– Before starting the test, install a
new spark plug in the cylinder
and tighten it down firmly, b 3.4
: Pull the boot off the spark plug
and connect it to terminal (2).
Warning!
The engine may start and
accelerate during the test.
If a spark is visible, the ignition
system is in order.
452RA134 VA
2
– Remove the shroud with rewind
starter, b 5.9
: Disconnect the ground wire (1).
: Disconnect the short circuit
wire (2).
: Take out the screw (3) with
washer.
: Remove the screw (4) with
connector tag.
– Remove the washers from
between the ignition module and
cylinder.
Check the ignition module and wires
for damage and replace as
necessary.
Install in the reverse sequence.
If no spark is visible in the
window (3), check the ignition
system with the aid of the
troubleshooting chart, b 8.7.
: Attach ground terminal (1) to the
spark plug.
: Use adjusting knob (4) to set
spark gap to about 2 mm.
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BR 500, BR 550, BR 600
8.5
5
6 2
: Fit screw (6) with ignition module
(4), washer (2) and washer (5) in
position.
452RA131 VA
4
452RA166 VA
3
452RA139 VA
1
Spark Plug Boot
– Remove the shroud with rewind
starter, b 5.2
: Rotate the flywheel until the
raised portion (arrow) is in line
with the ignition module.
– Pull the boot off the spark plug.
: Fit screw (1) with ignition module
(4), connector tag (3) and
washer (5) in position.
: Use suitable pliers to pull the leg
spring out of the spark plug boot.
Pay attention to correct installed
positions of the washers (5) and the
connector tag (3).
– Slide the spark plug boot back a
little in the direction of the ignition
module
2
1
452RA136 VA
Install all other parts in the reverse
sequence.
– Unhook the leg spring from the
ignition lead.
: Slide the setting gauge
4118 890 6401 (1) between the
arms of the ignition module and
the flywheel.
– Coat the end of the ignition lead
with STIHL Press Fluid OH 723,
b 13.
If the ignition lead is frayed or
damaged, install a new ignition
module.
– Press the ignition module against
the setting gauge.
: Tighten down the screws (2)
firmly.
452RA135 VA
212RA291 VA
Install all other parts in the reverse
sequence.
: Check that the wires are correctly
positioned in the air guide
shroud (arrow).
: Pinch the hook of the leg spring
into the center of the lead, i.e.
about 15 mm from the end of the
lead.
BR 500, BR 550, BR 600
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47
8.6
Testing the Wiring
Harness
452RA132 VA
452RA137 VA
1
: Pull the lead back into the boot so
that the leg spring locates
properly inside it.
If the spark plug, ignition lead and
spark plug boot are in order, test the
resistance of the short circuit wire,
ground wire and contact spring.
Install in the reverse sequence.
– Remove the shroud with rewind
starter, b 5.9
: Pull the short circuit wire (1) off
the connector.
– Connect the ohmmeter to ground
and the short circuit wire.
– Move the setting lever on the
control handle to “0“and hold it
there.
The measured resistance must be
about 0 Ω. If the reading is much
higher, there is a break in the wire
and the throttle cable has to be
replaced together with the wires.
– Move the setting lever on the
control handle to “#“.
The measured resistance must be
infinitely high. If the reading is much
lower, there is a break in the wire
and the throttle cable has to be
replaced together with the wires.
If no fault is found, carry out the
following checks:
– Examine flywheel for damage,
b 7.7
– Check air gap between flywheel
and ignition module, b 8.4
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BR 500, BR 550, BR 600
8.7
Ignition System Troubleshooting
Engine does not run
Check the spark plug:
– Smeared with oil, black?
– Sooted?
– Electrode gap correct?
– Contacts shorted?
Clean the plug, reset
or replace
Check spark plug boot:
– Firmly seated on plug (leg spring)?
– Leg spring hook in center of ignition lead?
– Boot damaged?
If necessary, install new spark plug boot
and/or leg spring
Test ignition system with
ZAT 3 or ZAT 4
(use ZAT 3 as main spark gap
– see TI 32.94)
1
BR 500, BR 550, BR 600
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49
1
Powerful
spark?
yes
no
Check air gap
and reset if necessary
Check flywheel:
Pole shoes have turned blue?
Install new flywheel
Disconnect short circuit wire from
ignition module
Check ignition lead:
– Severe chafing?
– Spark plug boot: Holes/cracks?
Resistance: spark plug boot to ground:
spec. 1.5 – 12 kΩ
– Check resistance of ignition lead:
spec. < 10 Ω,
If necessary, install new spark plug boot
and/or ignition lead
2
50
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3
BR 500, BR 550, BR 600
2
3
Check operation
of setting lever
– Short circuit wire chafed?
– Contact gap (contact springs)
If necessary, install new ignition lead
and/or contact springs
Re-connect short circuit wire
yes
Powerful
spark?
no
Install new
ignition module
yes
Check “#“/“0“ function on
setting lever
or separate
stop switch
BR 500, BR 550, BR 600
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Engine
runs
no
Look for fault in fuel system
or carburetor,
check engine for leaks,
check position of flywheel on
crankshaft
51
9.
9.1
Control Handle
Throttle Trigger/Interlock
Lever
9.2
Setting Lever
2
1
: Take out the screw (arrow).
3
: Swing the lever (1) sideways and
remove it upwards.
– Remove the interlock lever,
b 9.1
– If necessary, take out the grub
screw (arrow).
: Remove the torsion spring (1).
452RA145 VA
452RA144 VA
452RA140 VA
1
– Remove the control handle.
: Take out the screw (2) and
remove the cam (3).
1
: Take out the screws (arrows)
: Remove the interlock lever.
: Remove the setting lever (1).
– Remove the outer handle
molding (1).
Install in the reverse sequence.
Install in the reverse sequence.
452RA146 VA
1
452RA143 VA
452RA141 VA
1
– Adjust the throttle cable, b 9.3.2
2
: Remove the torsion spring (1).
452RA147 VA
3
452RA142 VA
1
– Make sure the teeth of the setting
lever mesh with those of the cam.
: Remove the throttle trigger (2)
with lever (3).
– Disconnect the throttle cable.
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BR 500, BR 550, BR 600
9.3
9.3.1
Throttle Cable
Removing and Installing
– Remove the shroud with rewind
starter, b 5.9
9.3.2
Adjusting
1
– Remove the filter housing, b 6.1
– Disconnect throttle cable from
the carburetor, b 6.2.2
1
: Remove the switch (1).
452RA150 VA
452RA148 VA
– Disconnect wires from the
ignition module, b 8.4
– Remove the shroud with rewind
starter, b 5.9
: Pull the wires out of the
guides (arrows).
The throttle lever must butt against
the stop on the carburetor cover
(arrow) when the throttle trigger is
pulled as far as it will go (full
throttle), and butt against the idle
speed screw (1) when the throttle
trigger is in the idle position.
– Remove the throttle cable.
Install in the reverse sequence.
Make sure the wires are installed
correctly.
1
452RA149 VA
To adjust the throttle cable, squeeze
the throttle trigger as far as stop.
: Pull the throttle cable (1) out of
the guides (arrows) on the inner
fan housing.
452RA152 VA
452RA151 VA
– Remove cam from setting lever,
b 9.2
: Carefully push the switch onto
the fixing pins (arrows).
– Adjust the throttle cable, b 9.3.2
: Turn the grub screw (arrow) with
a suitable tool until the throttle
lever butts against the carburetor
cover.
– Check idle position.
BR 500, BR 550, BR 600
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53
10.
10.1
Install in the reverse sequence.
AV System
Spring Elements
10.2
Backplate
2
452RA084 VA
452RA093 VA
1
– Take the powerhead off the
backplate, b 10.2
– Remove the shroud with rewind
starter, b 5.9
: Use pliers to carefully unscrew
the springs (1) with bearing plugs
(2).
– Drain the fuel tank.
– If necessary, unscrew the bearing
plugs from the springs.
– Pry out the connector with fuel
hoses, b 6.6
Take care to ensure that no parts
drop on the floor.
Install in the reverse sequence.
: Take out the screws (arrows).
– Remove the powerhead from the
backplate.
: Screw home the springs and
bearing plugs as far as stop
(arrows).
452RA085 VA
452RA094 VA
– Remove the tank, b 6.7
BR 500 only
: Remove soundproofing (arrows).
Install all other parts in the reverse
sequence.
54
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BR 500, BR 550, BR 600
11.
11.1
Fan
Outer Fan Housing
2
1
3
: Push the locking tabs (arrows)
down and lift the protective
screen (1) upwards and away.
: Unclip the throttle cable (1) with
grommet (3) from the hose
clamp (2).
Install in the reverse sequence.
: Take out the screw (arrow).
2
452RA088 VA
1
452RA154 VA
452RA086 VA
1
: Take out the screws (arrows).
: Remove the outer fan
housing (1).
: Remove the elbow (2).
: Remove the hose clamp (2) and
pleated hose.
1
452RA087 VA
1
Install in the reverse sequence.
: Locate lugs (1) on bottom of
protective screen in the holes
(arrows) in the base of the
backplate.
– Carefully push the upper half of
the protective screen against the
backplate until the locking tabs
snap into position.
1
2
452RA155 VA
Install all other parts in the reverse
sequence.
: Disconnect the lower half of the
antistatic wire (1) from the upper
half (2).
– Take the powerhead off the
backplate, b 10.2
BR 500, BR 550, BR 600
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55
11.2
Inner Fan Housing
11.3
– Remove the fanwheel, b 11.3
Fanwheel
1
– Remove the elbow, b 11.1
1
– Remove the air guide shroud,
b 7.2
452RA096 VA
452RA090 VA
– Remove the carburetor, b 6.2.2
– Remove the antistatic wire,
b 11.4
– Remove outer fan housing,
b 11.1
BR 500 only
: If the fan housing is replaced, the
soundproofing liner (1) must be
fitted at the engine side.
– Use combination wrench
4180 890 3400 to unscrew the
spark plug.
: Screw the locking screw
4282 890 2700 (1) fully home.
: Take out the screws (arrows)
– Remove the engine.
Install in the reverse sequence.
Do not lubricate the thread of the
fanwheel.
452RA098 VA
452RA097 VA
Always use the specified locking
screw to avoid any risk of damaging
the piston.
: When installing, check that the
groove in the manifold is properly
seated in the fan housing (arrow).
– Check that the throttle cable and
fuel hoses are correctly
positioned.
Install all other parts in the reverse
sequence.
452RA089 VA
1
: Unscrew the fanwheel (1)
counterclockwise.
Right-hand thread. Very high
release torques may be necessary
after long periods of operation.
56
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BR 500, BR 550, BR 600
11.4
Install in the reverse sequence.
2
Antistatic Wire
1
– Remove the fanwheel, b 11.3
452RA164 VA
452RA091 VA
Do not lubricate the thread of the
fanwheel.
The machine may be operated only
with a properly installed antistatic
wire.
: Take out the screw (1).
: Remove the antistatic wire (2).
: Check that the hook on the
antistatic wire is always
connected to the eye (arrow).
Install in the reverse sequence.
BR 500, BR 550, BR 600
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452RA165 VA
452RA092 VA
Check installed position of antistatic
wire.
: When installing, make sure the
crimping (arrow) on the cable lug
faces outwards.
: Make sure the sleeve on the
antistatic wire is always clipped
into the retainer (arrow).
Install all other parts in the reverse
sequence.
Install all other parts in the reverse
sequence.
57
12.
Special Servicing Tools
No.
Part Name
Part No
Application
1
Compression tester
5910 850 2000
2
3
4
Locking screw
Installing tool
– with sleeve –
Carburetor and crankcase tester
4282 890 2700
5910 890 2212
5910 893 1704
1106 850 2905
Testing valves and piston rings for
leaks
Blocking the crankshaft
Fitting snap ring in piston
5
6
7
8
9
10
11
Hose
Nipple
Vacuum pump
Feeler gauge
Socket, DIN 3124, 13 mm
Puller
Torque wrench
1110 141 8600
0000 855 9200
0000 850 3501
4180 893 6400
5910 893 5608
1116 893 0800
5910 890 0311
12
Torque wrench
5910 890 0301
13
14
15
16
17
18
19
20
Socket, 17 mm
Puller
– Jaws (profile # 3.1)
Installing sleeve
Press sleeve
Combination wrench
Assembly drift
Setting gauge
5910 893 5610
5910 890 4400
1118 893 4602
1108 893 2405
4180 890 3400
1108 893 4700
4118 890 6401
21
22
Test flange
Bushing
1119 850 4201
0000 963 1008
23
24
25
26
27
Sealing plate
Ignition tester, ZAT 3
Ignition tester, ZAT 4
Puller
Screwdriver, T 27 x 200
0000 855 8106
5910 890 4520
5910 850 4503
5910 890 4501
5910 890 2415
58
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Rem.
Testing crankcase and carburetor for
leaks
Testing carburetor for leaks
Testing carburetor for leaks
Testing crankcase for leaks
Adjusting valve clearances
Flywheel nut
Removing flywheel
6 to 80 Nm; torque wrench
5910 890 0312 with optical/acoustic
signal may be used as an alternative
0.5 to 18 Nm; torque wrench
5910 890 0302 with optical/acoustic
signal may be used as an alternative
Releasing fanwheel
Universal puller
Removing oil seals
Installing oil seal
Installing oil seal
Spark plug
Removing and installing piston pin
Adjusting air gap between ignition
module and flywheel
Leakage test
For use with test flanges
1106 850 4201 and 1119 850 4201
Sealing exhaust port
Testing the ignition system
Testing the ignition system
Removing limiter caps
BR 500, BR 550, BR 600
13.
Servicing Aids
No.
Part Name
Part No
Application
1
2
3
Lubricating grease (225 g tube)
STIHL Press Fluid OH 723
STIHL special lubricant
0781 120 1111
0781 957 9000
0781 417 1315
4
5
Dirko sealant (100 g tube)
Standard commercial solventbased degreasant containing no
chlorinated or halogenated
hydrocarbons
Loctite 270 (50 ml bottle)
0783 830 2120
Sliding and pivot points
Rubber elements of AV system
Bearing bore in rope rotor,
rewind spring in rope rotor
Crankcase sealing faces
Cleaning crankshaft stub
6
BR 500, BR 550, BR 600
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0786 111 1109
Rem.
High-strength threadlocking adhesive
59
60
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BR 500, BR 550, BR 600
englisch / english
0455 452 0123. VA0.B12.FST. Printed in Germany
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