Stihl MS 231 User manual

STIH)
STIHL MS 231, 251 2010-10
All manuals and user guides at all-guides.com
all-guides.com

1MS 231, MS 231 C, MS 251, MS 251 C
q
© ANDREAS STIHL AG & Co. KG, 2010
RA_737_00_01_01
1. Introduction and
Safety Precautions 3
1.1 Introduction 3
1.2 Safety Precautions 4
2. Specifications 5
2.1 Engine 5
2.2 Fuel System 5
2.3 Ignition System 5
2.4 Chain Lubrication 5
2.5 Tightening Torques 6
3. Troubleshooting 8
3.1 Clutch 8
3.2 Chain Drive,
Chain Brake,
Chain Tensioner 9
3.3 Chain Lubrication 11
3.4 Rewind Starter 12
3.5 Ignition System 14
3.6 Carburetor 15
3.7 Engine 18
4. Clutch 19
4.1 Clutch Drum 19
4.2 Clutch 19
5. Chain Brake 20
5.1 Checking Operation 20
5.2 Brake Band 20
5.3 Brake Lever 21
5.4 Brake Lever on
Machines with
QuickStop Super 24
5.4.1 Adjusting
the brake cable 26
5.4.2 Brake cable
Removing
and Installing 27
5.5 Chain Tensioner 29
5.5.1 Quick Chain
Tensioner 30
5.5.2 Chain Catcher 30
5.6 Bar Mounting Stud 31
6. Engine 32
6.1 Muffler 32
6.2 Leakage Test 33
6.2.1 Preparations 33
6.2.2 Vacuum Test 34
6.2.3 Pressure Test 34
6.3 Oil Seals 35
6.3.1 Ignition side 35
6.3.2 Clutch side 36
6.4 Shroud 36
6.5 Engine 37
6.6 Cylinder / Crankshaft 38
6.7 Bearings / Crankshaft 41
6.8 Piston 42
6.9 Piston Rings 44
7. Ignition System 45
7.1 Ignition Timing 45
7.2 Preseparator 45
7.3 Install new
ignition module 45
7.4 Testing the
Ignition Module 47
7.5 Spark Plug Boot /
Ignition Lead 48
7.6 Flywheel 49
7.7 Short Circuit Wire 50
7.7.1 Testing 50
7.7.2 Removing and
Installing 50
7.7.3 Ground Wire 53
7.7.4 Contact Spring 53
7.8 Ignition System
Troubleshooting 55
8. Rewind Starter 58
8.1 General 58
8.2 Fan housing 58
8.3 Pawls 59
8.4 ErgoStart 60
8.5 Rope Rotor 61
8.6 Starter Rope / Grip 61
8.7 Tensioning
the Rewind Spring 62
8.8 Replacing
the Rewind Spring 63
9. Servicing
the AV System 66
9.1 AV Spring on Oil Tank 66
9.2 AV Spring on
Fuel Tank 66
9.3 AV Spring on
Handlebar 67
9.3.1 Stop Buffers 68
9.3.2 Buffers on Filter Base 69
9.4 Handlebar 69
10. Control Levers 71
10.1 Master Control Lever 71
10.1.1 Removing and
Installing 71
10.2 Throttle Trigger/
Lockout Lever 72
10.3 Throttle Trigger/
Lockout Lever –
QuickStop Super 73
10.3.1 Switch Lever
QuickStop Super 74
10.3.2 Lockout Lever –
QuickStop Super 75
10.3.3 Choke Rod 76
10.3.4 Throttle Rod 76
11. Chain Lubrication 78
11.1 Pickup Body 78
11.2 Oil Suction Hose 78
11.3 Oil Pump 78
11.4 Valve 80
12. Fuel System 81
12.1 Air Filter 81
12.2 Baffle 81
12.3 Filter Base 81
12.4 Air Guide Shroud 83
12.4.1 Air Guide Shroud –
Models with
Manual Fuel Pump 85
12.5 Carburetor 88
12.5.1 Leakage Test 89
Contents
All manuals and user guides at all-guides.com

2MS 231, MS 231 C, MS 251, MS 251 C
Contents
12.6 Servicing
the Carburetor 90
12.6.1 Metering Diaphragm 90
12.6.2 Inlet Needle 90
12.6.3 Pump Diaphragm 91
12.6.4 Lever on
Throttle Shaft 92
12.6.5 Adjusting Screws 93
12.7 Adjusting
the Carburetor 95
12.7.1 Basic Setting 95
12.7.2 Standard setting 96
12.8 Carburetor Carrier 97
12.9 Intake Manifold 98
12.10 Tank Vent 99
12.10.1 Testing 99
12.10.2 Removing and
Installing 100
12.11 Fuel Intake 101
12.11.1 Pickup Body 101
12.11.2 Fuel Hose 101
12.11.3 Fuel Hoses –
Manual Fuel Pump 105
12.11.4 Manual Fuel Pump 107
12.11.5 Tank Housing 108
13. Special
Servicing Tools 110
14. Servicing Aids 112
All manuals and user guides at all-guides.com

3MS 231, MS 231 C, MS 251, MS 251 C
1. Introduction and Safety Precautions
1.1 Introduction
This service manual contains
detailed descriptions of all the repair
and servicing procedures specific to
this power tool.
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.
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" 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 a
revised edition is issued.
The special tools mentioned in the
descriptions are listed in the chapter
on "Special Servicing Tools" in 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.
Symbols are included in the text and
pictures for greater clarity.
The meanings are as follows:
In the descriptions:
: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:
APointer
aDirection of movement
@4.2 =Reference to another
chapter, i.e. chapter 4.2
in this example.
Service manuals and all technical
information bulletins are intended
exclusively for the use of properly
equipped repair shops. They must
not be passed to third parties.
Servicing and repairs are made
considerably easier if the machine
is mounted to assembly stand (3)
5910 890 3101. To do this, secure
the mounting plate (2)
5910 850 1650 to the assembly
stand with two screws (1) and
washers.
The screws must not project since
they, depending on the machine,
may damage housings when the
machine is clamped in position.
Engage the bar mounting stud in the
outer bore in the mounting plate and
secure the machine in position with
the M 8 nut (arrow).
The machine is held in position on
the mounting plate by the screw
heads on the engine housing.
2710RA320 TG
2
3
1
2310RA000 TG
All manuals and user guides at all-guides.com

4MS 231, MS 231 C, MS 251, MS 251 C
Preparations for servicing
Remove the chain sprocket cover,
saw chain and guide bar before
carrying out repairs or mounting the
machine to the assembly stand.
Always use original STIHL
replacement parts.
They can be identified by the STIHL
part number,
the {
logo and the
STIHL parts symbol K
This symbol may appear alone on
small parts.
Storing and disposing of oils and
fuels
Collect fuel or lubricating oil in a
clean container and dispose of it
properly in accordance with local
environmental regulations.
1.2 Safety Precautions
If the machine is started up in the
course of repairs or maintenance
work, observe all local and country-
specific 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.
Do not smoke or bring any fire,
flame or other source of heat near
the fuel. All work with fuel must be
performed outdoors only. Spilled
fuel must be wiped away
immediately.
Always perform leakage test after
working on the fuel system and the
engine.
Exercise extreme caution while
carrying out maintenance and repair
work on the ignition system. The
high voltages which occur can
cause serious or fatal accidents.
Always wear suitable protective
gloves for operations in which
components are heated for
assembly or disassembly.
Improper handling may result in
burns or other serious injuries.
Always replace damaged parts.
Check disassembled parts for wear
or damage before re-installing –
replace as necessary.
Run the machine only with the
shroud mounted in position – there
is otherwise a risk of injury from the
fanwheel and a risk of engine
damage due to overheating.
The chapter on tightening torques
lists all machine components that
have to be tightened to a specific
torque or coated with threadlocking
adhesive. The specifications must
be maintained when tightening
down screws, nuts and other
fasteners in all the procedures
described in this service manual.
Fuel system – hose barb
connectors
Pull off or push on fuel hoses in line
with the connector, preferably by
hand, to ensure the tightness of the
fuel system.
Avoid damaging the hose barb
– do not use sharp-edged pliers,
screwdrivers, etc.
Do not cut open fuel hoses with a
knife or similar tool.
Do not re-use fuel hoses after
removal. Always install new hoses
– fuel hoses can be overstretched
during removal.
Install new fuel hoses either dry or
with the aid of STIHL press fluid,
b14.
Other press fluids are not approved
and may result in damage to the fuel
hoses.
Coat the ends of the hoses and the
connectors with STIHL press fluid
and then push the new hoses on to
the hose barbs, b14.
All manuals and user guides at all-guides.com

5MS 231, MS 231 C, MS 251, MS 251 C
2. Specifications
2.1 Engine
MS 231 MS 251
Displacement: 40.6 cm345.6 cm3
Bore: 41.5 mm 44.0 mm
Stroke: 30.0 mm 30.0 mm
Engine power to ISO 7293: 2.0 kW (2.7 bhp)
at 9,500 rpm
2.2 kW (3.0 bhp)
at 9,500 rpm
Maximum permissible engine speed
with bar and chain: 13,000 rpm 13,000 rpm
Idle speed: 2,800 rpm 2,800 rpm
Clutch: Centrifugal clutch without
linings
Centrifugal clutch without
linings
Clutch engages at: 3,500 rpm 3,500 rpm
Crankcase leakage test
at gauge pressure: 0.5 bar
under vacuum: 0.5 bar
2.2 Fuel System
Carburetor leakage test at
gauge pressure: 0.8 bar
Operation of tank vent at
gauge pressure: 0.5 bar
Fuel: as specified in instruction
manual
2.3 Ignition System
Air gap between ignition
module and fanwheel: 0.30 (+ 0.05/- 0.10) mm
Spark plug (resistor type): NGK CMR 6 H
Electrode gap: 0.5 mm
2.4 Chain Lubrication
Speed-controlled Ematic oil pump
Oil delivery rate: 8.0 (+/3.0) cm3/min
at 10,000 rpm
All manuals and user guides at all-guides.com
all-guides.com

6MS 231, MS 231 C, MS 251, MS 251 C
2.5 Tightening Torques
DG and P (Plastoform) screws are used in polymer and light metal 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
Nm
Remarks
Screw P 4x12 Chain tensioner cover 1.5
Screw P 5x18 Antivibration element / engine housing 4.0
Screw P 5x34 Antivibration element / tank housing 4.0
Screw P 4x12 Brake band/engine housing 2.0
Screw P 4x10 Brake cable retainer / tank housing 1.0 Q
Collar screw D 8x18 Collar stud for bar 16.0
Collar screw D 8x18 Collar stud for bar 16.0 B
Collar screw D 9x18 Collar stud for bar / engine housing
(repair solution)
16.0
Screw P 5x18 Cover, chain brake / engine housing 4.0
Nut M 5 Filter base / baffle / carburetor 3.5
Screw P 6x26.5 Handlebar / tank housing, right 6.0
Screw M 5x16 Handlebar / tank housing, bottom 5.0 2), 3)
Screw M 5x20 Hand guard / fan housing / engine housing 6.0 2)
Screw M 5x14 Shroud / engine housing 5.0
Screw P 5x16 Spiked bumper / engine housing 4.0
Screw D 4x12 Manifold / cylinder 4.0 1), 3)
Screw D 5x18 Bearing plug / cylinder 8.0 1), 3)
Screw P 5x18 Fan housing / engine housing 4.0
Screw P 4x12 Air baffle / engine housing 2.0
Carrier M 12x1 L Carrier / crankshaft 50.0
Screw P 6x28 Engine housing / bearing plug 6.0
Screw D 4x16 Oil pump 4.0 1), 3)
Screw M 5x16 Muffler / cylinder 10.0 2), 3)
Nut M 8x1 Flywheel / crankshaft 28.0 4)
Screw P 4x10 Retainer 1.0
All manuals and user guides at all-guides.com

7MS 231, MS 231 C, MS 251, MS 251 C
Fastener Thread size For component Torque
Nm
Remarks
Screw P 4x12 Pre-separator / engine housing 2.0
Screw P 4x10 Elbow connector / air guide shroud 1.6
M 10x1 Spark plug / cylinder 12.0
Screw D 4x20 Ignition module/cylinder 4.51), 3)
Screw D 5.3x41 Cylinder / engine housing 11.0
Remarks:
1) Screws with binding head
2) Micro-encapsulated screws
3) Waxed screws
4) Degrease crankshaft/flywheel and mount oil-free
Q) QuickStop Super
B) Quick chain adjuster
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.
Coat micro-encapsulated screws with medium strength Loctite 242 or 243 before reinstalling.
Power screwdriver setting for polymer: DG and P screws max. 500 rpm
Do not use an impact wrench for releasing or tightening screws.
Do not mix up screws with and without binding heads.
All manuals and user guides at all-guides.com

8MS 231, MS 231 C, MS 251, MS 251 C
3. Troubleshooting
3.1 Clutch
Condition Cause Remedy
Saw chain stops under full load Clutch shoes badly worn Install new clutch
Clutch drum badly worn Install new clutch drum
Saw chain rotates at idle speed Engine idle speed too high Readjust idle speed screw LA
Clutch springs stretched Replace the clutch springs or install
new clutch
Clutch springs broken Replace the clutch springs
Loud noises Clutch springs stretched Replace all clutch springs
Needle cage damaged Fit new needle cage
Clutch shoe retainer broken Install new retainer or clutch
Clutch shoes and carrier worn Install new clutch
All manuals and user guides at all-guides.com

9MS 231, MS 231 C, MS 251, MS 251 C
3.2 Chain Drive, Chain Brake, Chain Tensioner
Condition Cause Remedy
Chain sprocket wears rapidly Chain not properly tensioned Tension chain as specified
Wrong chain pitch Fit chain of correct pitch
Insufficient chain lubrication Check chain lubrication
Saw chain stops under full load Clutch shoes badly worn Install new clutch
Clutch drum badly worn Install new clutch drum
Brake band blocked Check freedom of movement and
operation of brake band
Saw chain rotates at idle speed Engine idle speed too high Readjust idle speed screw LA
Clutch springs stretched Replace the clutch springs or install
new clutch
Clutch springs broken Replace the clutch springs
Saw chain does not stop
immediately when brake is
activated
Brake spring stretched or broken Fit new brake spring
Brake band stretched or worn Fit new brake band
Clutch drum worn Install new clutch drum
All manuals and user guides at all-guides.com

10 MS 231, MS 231 C, MS 251, MS 251 C
Condition Cause Remedy
QuickStop Super
Coasting brake does not disengage
even though lockout lever is
depressed
Brake cable stretched Readjust brake cable
Brake cable disconnected or
broken
Reconnect or replace brake cable
QuickStop Super
Coasting brake does not disengage
properly even though lockout lever
is depressed
Too much free travel on lockout
lever
Adjust brake cable
QuickStop Super
Braking action of coasting brake
inadequate – lockout lever not
depressed
Brake cable overtensioned Adjust brake cable
All manuals and user guides at all-guides.com
all-guides.com

11MS 231, MS 231 C, MS 251, MS 251 C
3.3 Chain Lubrication
In the event of trouble with the
chain lubrication system, check and
rectify other sources of faults
before disassembling the oil pump.
.
Condition Cause Remedy
Chain receives no oil Oil inlet hole in guide bar is blocked Clean oil inlet hole
Intake hose or pickup body clogged
or intake hose ruptured
Fit new intake hose and pickup
body
Valve in oil tank blocked Clean or replace valve
Teeth on worm worn Install new worm
Oil pump damaged or worn Install new oil pump
Machine losing chain oil Oil pump damaged or worn Install new oil pump
Oil suction hose connection
damaged
Install new oil intake hose
Engine housing cracked Install new engine housing
Oil pump delivers insufficient oil Oil pump damaged or worn Install new oil pump
Worm driver is loose Install new worm
All manuals and user guides at all-guides.com

12 MS 231, MS 231 C, MS 251, MS 251 C
3.4 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
Starter rope does not rewind Rewind spring very dirty or
corroded
Clean or replace rewind spring
Insufficient spring tension Check rewind spring and increase
tension
Rewind spring broken Fit new rewind spring
Starter rope cannot be pulled out
far enough
Spring overtensioned Check rewind spring and reduce
tension
Starter rope can be pulled out
almost without resistance
(crankshaft does not turn)
Guide peg on pawl or pawl itself is
worn
Fit new pawl
Spring clip on pawl fatigued Fit new spring clip
Spring clip installed wrong Install spring clip correctly
...Models with ErgoStart Guide pegs on pawls or pawls
themselves are worn
Fit new pawls
Torsion springs on flywheel
fatigued, pawls worn or sticking
Clean seats on pawls or replace
pawls and torsion springs if
necessary
Lugs on carrier worn Install new carrier
Spring loop in spring housing not
attached to carrier
Attach spring loop to carrier
Starter rope is difficult to pull –
models with ErgoStart
Spring in spring housing fatigued Install new spring housing
All manuals and user guides at all-guides.com

13MS 231, MS 231 C, MS 251, MS 251 C
Condition Cause Remedy
Starter rope is difficult to pull or
rewinds very slowly
Starter mechanism is very dirty Thoroughly clean complete starter
mechanism
At very low outside temperatures:
Lubricating oil on rewind spring
becomes viscous (spring windings
stick together) or moisture has got
onto the rewind spring (spring
windings frozen together)
Coat rewind spring with a small
amount of standard solvent-based
degreasant (containing no
chlorinated or halogenated
hydrocarbons), then pull rope
carefully several times until normal
action is restored
All manuals and user guides at all-guides.com

14 MS 231, MS 231 C, MS 251, MS 251 C
3.5 Ignition System
Condition Cause Remedy
Engine runs roughly, misfires,
temporary loss of power
Spark plug boot is loose Press boot firmly onto spark plug
and fit new spring if necessary
Spark plug sooted, smeared with oil Clean the spark plug or replace if
necessary.
If sooting keeps recurring, check air
filter
Fuel/oil mixture
– too much oil
Use correct mixture of fuel and oil
Incorrect air gap between ignition
module and flywheel
Set air gap correctly
Flywheel cracked or
damaged or pole shoes have
turned blue
Install new flywheel
Ignition timing wrong, flywheel out
of adjustment
– key in flywheel has sheared off
Install new flywheel
Weak magnetization in flywheel Install new flywheel
Irregular spark Check operation of switch shaft/
contact spring and ignition module
Damaged insulation or break in
ignition lead or short circuit.
Check ignition lead/module,
replace ignition module if
necessary.
Check operation of the spark plug,
clean or replace spark plug if
necessary.
All manuals and user guides at all-guides.com

15MS 231, MS 231 C, MS 251, MS 251 C
3.6 Carburetor
Condition Cause Remedy
Carburetor floods; engine stalls Inlet needle not sealing
– foreign matter in valve seat or
cone
Remove and clean the inlet needle,
clean the carburetor
Inlet needle worn Replace the inlet needle
Inlet control lever sticking on
spindle
Check the inlet control lever and
replace if necessary.
Helical spring not located on nipple
of inlet control lever
Remove the inlet control lever and
refit it correctly
Perforated disc on diaphragm is
deformed and presses constantly
against the inlet control lever
Fit a new metering diaphragm
Metered diaphragm deformed Fit a new metering diaphragm
Poor acceleration Setting of low speed screw too lean Check basic carburetor setting,
correct if necessary
Setting of high speed screw too
lean
Check basic carburetor setting,
correct if necessary
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 a new metering diaphragm
Tank vent faulty Replace tank vent
Leak on fuel hose from tank to
carburetor
Seal connections or install new fuel
hose
Engine loses power during
acceleration
Sealing ring or spring in accelerator
pump worn or damaged
Install new carburetor
All manuals and user guides at all-guides.com
all-guides.com

16 MS 231, MS 231 C, MS 251, MS 251 C
Condition Cause Remedy
Engine will not idle, idle speed too
high
Throttle shutter opened too wide by
idle speed screw (LA)
Reset idle speed screw (LA)
correctly
Oil seals/engine pan leaking Seal or replace oil seals/engine pan
Throttle shutter does not close Install new carburetor
Engine stops while idling Idle jet bores
or ports blocked
Clean the carburetor
Low speed screw too rich or
too lean
Reset low speed screw (L)
correctly
Setting of idle speed screw LA
incorrect – throttle shutter
completely closed
Reset idle speed screw (LA)
correctly
Tank vent faulty Replace tank vent
Leak on fuel hose from tank to
carburetor
Seal connections or install new fuel
hose
Saw chain rotates at idle speed Engine idle speed too high Readjust with idle speed screw
LA (counterclockwise)
Clutch springs stretched or fatigued Replace the clutch springs or install
new clutch
Clutch spring hooks broken Replace the clutch springs
All manuals and user guides at all-guides.com

17MS 231, MS 231 C, MS 251, MS 251 C
Condition Cause Remedy
Engine speed drops quickly under
load – low power
Air filter dirty Clean air filter or replace if
necessary
Throttle shutter not opened fully Check throttle rod
Tank vent faulty Replace tank vent
Fuel pickup body dirty Install new pickup body
Fuel strainer dirty Clean fuel strainer in carburetor,
replace if necessary
Leak on fuel hose from tank to
carburetor
Seal connections or install new fuel
hose
Setting of high speed screw Htoo
rich
Check basic carburetor setting,
correct if necessary
Main jet bores or ports blocked Clean the carburetor
Pump diaphragm damaged or
fatigued
Fit new pump diaphragm
Ignition timing wrong, flywheel out
of adjustment
– key in flywheel has sheared off
Install new flywheel
Engine running extremely rich, has
no power and a very low maximum
speed
Choke shutter does not open Check carburetor and choke shaft,
service or replace if necessary
All manuals and user guides at all-guides.com

18 MS 231, MS 231 C, MS 251, MS 251 C
3.7 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
Oil seals in engine damaged Replace the oil seals
Engine pan leaking or
damaged (cracks)
Inspect engine pan, re-seal or
replace if necessary.
Intake manifold damaged / bore
blocked
Clean bore or install new manifold.
Engine does not deliver full power
or runs erratically
Piston rings worn or broken Fit new piston rings
Muffler / spark arresting screen
carbonized
Clean the muffler (inlet and
exhaust), replace spark arresting
screen, replace muffler if necessary
Air filter dirty Clean or replace air filter
Fuel hose kinked or torn Fit new hose or position it free from
kinks
Intake manifold damaged / bore
blocked
Clean bore or install new manifold.
Engine overheating Insufficient cylinder cooling. Air
inlets in fan housing blocked or
cooling fins on cylinder very dirty
Thoroughly clean all cooling air
openings and the cylinder fins
Air inlet in fan housing dirty Clean air inlet on fan housing
All manuals and user guides at all-guides.com

19MS 231, MS 231 C, MS 251, MS 251 C
4. Clutch
4.1 Clutch Drum
– Remove and install the clutch
drum, see instruction manual.
– Remove the needle cage.
– Clean the needle cage and
crankshaft stub, b14
– Lubricate the needle cage and
crankshaft stub, b14
– Inspect the clutch drum (1) for
signs of wear.
If there are signs of serious wear on
the inside diameter of the clutch
drum (1), check the remaining wall
thickness. If it is less than about
80% of the original thickness, install
a new clutch drum.
– Install the clutch drum.
4.2 Clutch
– Troubleshooting, b4.2
– Remove the clutch drum, b4.1
– Remove the shroud, b6.4
!
80%
100%
5902RA018 TG
1
:Pull boot (1) off the spark plug.
– Unscrew the spark plug.
:Hold the locking strip (1)
0000 893 5904 so that the flat
side of its metal top faces the
piston and then push it into the
cylinder.
:The locking strip (1)
0000 893 5904 must butt against
the cylinder wall (arrow) and the
flat side of its metal top must rest
on the piston crown
– as shown in the illustration.
2310RA001 TG
1
2310RA002 TG
1
2310RA003 TG
1
:Apply wrench to hexagon (arrow)
and unscrew the clutch (1) – left-
hand thread.
Installing
Fit the cover washer (1) so that the
word "TOP" faces outwards.
:Position the clutch (2) on the
crankshaft stub so that the raised
hexagon (arrow) faces outwards.
:Fit the clutch (2) and tighten it
down firmly – left-hand thread.
– Remove the locking strip from the
cylinder.
– Reassemble all other parts in the
reverse sequence.
TOP
2310RA004 TG
1
TOP
2310RA005 TG
1
2
All manuals and user guides at all-guides.com