STIHL FS 350 Service manual.pdf

STIHL FR 350, 450 2003-04

RA_U1_00_00.fm Seite 0 Donnerstag, 2. Mrz 2006 11:47 11

Schwarz Proze 45,0 240,0 LPI

STIH)

STIHL FS 120, 200, 300, 350, 400, 450,

STIH)

www.mymowerparts.com Call 606-678-9623 or 606-561-4983

www.mymowerparts.com Stihl

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1. Introduction 2

2. Specifications 3

2.1 Engine 32.2 Fuel System 32.3 Ignition System 42.4 Gearhead 42.5 Special Accessories 42.5.1 For User 42.5.2 For Service 42.6 Tightening Torques 5

3. Clutch 7

3.1 Removing and Installing 73.2 Clutch Carrier 8

4. Engine 9

4.1 Exhaust Muffler/Spark Arresting Screen 9

4.2 Leakage Test 104.2.1 Preparations 104.2.2 Pressure Test 114.2.3 Vacuum Test 114.3 Oil Seals 124.4 Exposing the Cylinder 134.5 Cylinder and Piston 144.5.1 Removal 144.5.2 Installation 154.6 Piston Rings 174.7 Crankcase 174.7.1 Removing Crankshaft 174.7.2 Installing Crankshaft 204.8 Decompression Valve 23

5. Ignition System 23

5.1 Spark Plug Boot 235.2 Ignition Lead

(FS 400/450, FR 450) 245.3 Ignition Module 255.3.1 Ignition Timing 265.3.2 Removing and Installing

(FS 120...350, FR 350) 265.3.3 Removing and Installing

(FS 400/450, FR 450) 275.4 Flywheel 285.5 Short Circuit Wire 29

6. Rewind Starter 30

6.1 General 306.2 Rewind Spring 306.2.1 Replacing 306.2.2 Tensioning 316.3 Starter Rope/Starter

Grip (ElastoStart) 32

7. Throttle Control 33

7.1 Throttle Trigger/InterlockLever (Bike Handle) 33

7.2 Contact Springs/DetentSpring in Control Handle(Bike Handle) 34

7.3 Throttle Trigger/InterlockLever (Loop Handle) 34

7.4 Slide Control(Loop Handle) 35

7.5 Throttle Cable 367.5.1 Replacing 367.5.2 Adjusting 37

8. Fuel System 38

8.1 Air Filter 388.2 Carburetor 398.2.1 Removing and Installing

(FS 120...350, FR 350) 398.2.2 Removing and Installing

(FS 400/450, FR 450) 408.2.3 Leakage Test 418.2.4 Adjusting

(three screws) 428.2.5 Adjusting

(one screw) 438.3 Tank Vent 448.4 Pickup Body 448.5 Fuel Tank/

Hoses 458.6 Manual

Fuel Pump 47

9. AV System 47

9.1 Repair(FS 120/200) 47

9.2 Repair(FS 300...450) 48

9.3 Repair(FR 350/450) 50

10. Shaft 51

10.1 Bike Handle(FS 120/200) 51

10.2 Bike Handle(FS 300...450) 51

10.3 Loop Handle 5210.4 Drive Shaft/

Flexible Liner 5210.5 Flexible Shaft

(FR 350/450) 5310.6 Drive Tube 5410.7 Housing

(FR 350/450) 56

11. Cutting ToolDrive 56

11.1 Gearhead 5611.2 Clutch Drum 57

12. Support Frame(FR 350/450) 58

12.1 Repair 58

13. Special ServicingTools and Aids 59

13.1 Special Servicing Tools 5913.2 Servicing Aids 61

2000, Andreas Stihl AG & Co., Waiblingen

CONTENTS

qS

FS 120, 200, 300, 350, 400, 450, FR 350, 450 1

This service manual contains de-tailed descriptions of all the repairand servicing procedures specificto this power tool series.There are separate handbooks forservicing procedures for stand-ardized parts and assemblies thatare installed in several STIHLpower tool models. Reference ismade to these handbooks in theappropriate chapters in thismanual.

As the design concept of modelsFS 120, FS 200, FS 300, FS 350,FS 400, FS 450 and FR 350, FR450 is almost identical, the descrip-tions and servicing procedures inthis manual generally apply to allmodels. Differences are describedin detail.

You should make use of theillustrated parts lists while carryingout repair work. They show theinstalled positions of the individualcomponents and assemblies.

Refer to the latest edition of therelevant parts list to check the partnumbers of any replacement partsneeded.Parts lists on microfiche and CD-ROM are always more up to datethan printed lists.

A fault on the power tool may haveseveral causes. Consult thetroubleshooting charts for all as-semblies in the "Standard Repairs,Troubleshooting" handbook.

Refer to the "Technical Informa-tion" bulletins for engineeringchanges which have been intro-duced since publication of thisservice manual. Technical informa-tion bulletins also supplement theparts list until a revised edition isissued.

The special servicing tools mentio-ned in the descriptions arelisted in the last chapter of thismanual.Use the part numbers to identifythe tools in the "STIHL SpecialTools" manual.The manual lists all specialservicing tools currently availablefrom STIHL.

Symbols are included in the textand pictures for greater clarity.The meanings are as follows:

In the descriptions:

= Action to be taken asshown in the illustration(above the text)

- = Action to be taken thatis not shown in theillustration(above the text)

In the illustrations:

= Pointer

= Direction of movement

Service manuals and all technicalinformation bulletins describingengineering changes are intendedexclusively for the use of STIHLservicing dealers. They must notbe passed to third parties.

Servicing and repairs are madeconsiderably easier if the machineis mounted on assembly stand (2)5910 890 3100 with the aid ofclamp (1) 5910 890 8800.

Secure the clamp to the assemblystand with two washers and twoM8 nuts.

Servicing and repairs to the power-head are considerably easier if it ismounted on assembly stand (2)5910 890 3100 with the aid ofclamping plate (1) 5910 890 2101.First remove the clutch housingand secure the powerhead to thestand with two M6x20 and twoM10x25 hex. head screws.

The machine or powerhead canthen be swivelled to the best posi-tion for the ongoing repair and thisleaves both hands free.

Always use original STIHLreplacement parts.They can be identified by theSTIHL part number,the STIHLand the STIHL parts symbol(The symbol may appear alone onsmall parts.

1. INTRODUCTION

250R

A228

1

2

VA

250R

A227

VA

2

1

2 FS 120, 200, 300, 350, 400, 450, FR 350, 450

2.1 Engine

STIHL single cylinder two-stroke engine with special impregnated cylinder bore

FS 120/300 FS 200/350 FS 400 FS 450FR 350 FR 450

Displacement: 30.8 cm3 36.3 cm3 40.2 cm3 44.3 cm31.88 cu.in 2.21 cu.in 2.45 cu.in 2.70 cu.in

Bore: 35 mm 38 mm 40.0 mm 42.0 mm1.38 in 1.49 in 1.57 in 1.65 in

Stroke: 32 mm 32 mm 32 mm 32 mm1.26 in 1.26 in 1.26 in 1.26 in

Power output: 1.3 kW (1.8 bhp) 1.6 kW (2.2 bhp) 1.9 kW (2.6 bhp) 2.1 kW (2.8 bhp)at 9,000 rpm

Max. permissible engine speedwithout cutting tool(cut-off speed): 12,500 1000 rpm 12,500 800 rpmIdle speed: 2,800 rpmBearings: Crankshaft supported in heavy-duty ball bearings, needle cages on

small and big endsPiston pin diameter: 10 mm (0.39 in)Rewind starter: ElastoStartPawls: Single pawl systemReserve pull on rope rotor: min. 1/2 turnStarter rope: 3.0 mm (0.12 in) dia. x 800 mm (31.5 in)Clutch: Centrifugal clutch without liningsClutch engages at: 4,300 rpmCrankcase leakagetestat gauge pressure: 0.5 bar (7.25 psi)under vacuum: 0.5 bar (7.25 psi)

2.2 Fuel System

Carburetor: Diaphragm carburetorStandard setting on carburetorswith three adjusting screwsHigh speed screw H: Open approx. 1 turnLow speed screw L: Open approx. 1 turnCarburetor leakage testat gauge pressure: 0.8 bar (11.6 psi)Function of tank ventat gauge pressure: 0.3 bar (4.35 psi)under vacuum: 0.05 bar (0.725 psi)Fuel tank capacity: 0.64 l (1.35 US pt) 0.68 l (1.44 US pt)Octane rating: min. 90 RON (US/CAN; pump octane min. 87)Fuel mixture: Regular brand name gasoline

and two-stroke engine oilMix ratio: 50:1 with STIHL two-stroke engine oil

25:1 with other brand name two-stroke, air-cooled engine oilsAir filter: Paper filter

2. SPECIFICATIONS

FS 120, 200, 300, 350, 400, 450, FR 350, 450 3

2.3 Ignition System Type: Electronic magnetoignition (breakerless)with integral trigger unitand electronic speedgovernor

Air gap: 0.2 - 0.5 mm (0.008 - 0.020 in)Length of ignition lead: 305 mm * (12 in)*Spark plug (suppressed): Bosch WSR 6F,

NGK BPMR 7 A orChampion RCJ 6Y

Electrode gap: 0.5 mm (0.020 in)Splark plug thread: M14x1.25Length of thread: 9.5 mm (0.37 in)

2.4 Gearhead Type: Spiral-toothedbevel gear drive

Gear ratio: 1:1.4 **1:1.235

Bearings: Deep groove ball bearings

Lubrication: STIHL gear lubricant 0781 120 1117(7 g / 0.25 oz)

2.5 Special Accessories

2.5.1 For User Full harnessSafety glassesTransport guard formetal cutting toolsSTIHL gear lubricant (80 g/3 oz tube) 0781 120 1109STIHL gear lubricant (80 g/3 oz tube) 0781 120 1117

2.5.2 For Service Carburetor parts kit 4134 007 1060Set of gasketsfor FS 120, 200, 300, 350, FR 350 4134 007 1050Set of gasketsfor FS 400, 450, FR 450 4128 007 1050

* FS 400/450 only** FS 120, 200, 350 and 450

4 FS 120, 200, 300, 350, 400, 450, FR 350, 450

DG and P screws (Plastoform) are used in polymer and lightmetal components. These screws form a perma-nent thread when they are installed for the first time. They can be removed and installed as often as necessarywithout detrimentally affecting the strength of the screwed assembly, providing the specified tightening torque isobserved. For this reason it is essential to use a torque wrench.

Fastener Thread For component Torque Remarkssize Nm lbf.ft

Self-tapping screw IS-B3.5x6.5 Rewind spring/fan housing 1.5 1.1Self-tapping screw IS-B4.2x9.5 Muffler/spark arresting screen 2.5 1.8 1) 2)Spline screw IS-DG4x20 Ignition module/crankcase 4.5 3.3 3) 4) 5)Spline screw IS-DG5x24 Ignition module/crankcase 6.0 4.4 1) 2)Spline screw IS-DG5x12 AV sleeve/drive tube (fixing screw) 2.5 1.8 3)Spline screw IS-DG5x12 Guard ring/gear housing 5.0 3.7 1) 4)Spline screw IS-DG5x20 Fan housing/crankcase 6.0 4.4Spline screw IS-DG5x20 Fan housing/shroud/crankcase 6.0 4.4Spline screw IS-DG5x20 Carburetor housing/crankcase/

cylinder 6.0 4.4Spline screw IS-DG5x20 Filter housing/ground wire/

crankcase 6.0 4.4Spline screw IS-DG5x20 Ground wire/crankcase 6.0 4.4 1) 2)Spline screw IS-DG5x26 Fuel tank/crankcase 6.0 4.4Spline screw IS-DG5x24 Bracket/crankcase 6.0 4.4 1)Spline screw IS-DG5x20 Shroud/clutch housing 6.0 4.4Spline screw IS-DG5x26 Guard plate/fuel tank/

crankcase 6.0 4.4 1) 2)Spline screw IS-DG5x28 Cylinder/crankcase 10.5 7.5Spline screw IS-DG5x24 Muffler/crankcase 8.5 6.3Spline screw IS-DG5x24 Muffler/cylinder 8.5 6.3Spline screw IS-DG5x24 Crankcase 8.5 6.3Spline screw IS-DG5x24 Clutch housing/crankcase 8.5 6.3 1) 2) 4) 5)Spline screw IS-DG5x24 Clutch housing/crankcase 6.0 4.4 3)Spline screw IS-DG6x28 Clutch housing/drive tube 12.0 8.8 1) 6)Spline screw IS-DG5x24 Clutch housing/drive tube 8.5 6.3 4)Spline screw IS-DG5x24 Gear housing/drive tube 8.5 6.3 2) 3) 5)Spline screw IS-DG5x25 Gear housing/drive tube

Stage 1 1.5 1.1 1) 4)Stage 2 7.5 5.5 1) 4)

Collar nut M5 Filter housing/carburetor housing 3.5 2.6Collar screw M5/P6 Carburetor housing 4.0 3.0Spline screw IS-M5x12 Clamp/control handle/

drive tube (loop handle) 2.0 1.5 3) 4)Spline screw IS-M5x16 AV sleeve/drive tube (clamp screw) 5.5 4.0 3)Spline screw IS-M5x12 Clamp/control handle/drive tube 2.0 1.5 2) 5)Spline screw IS-M5x16 Clamp/drive tube (for harness) 4.5 3.3 3)Spline screw IS-M5x30 Control handle (bike handle) 2.0 1.5 6)

2.6 Tightening Torques

FS 120, 200, 300, 350, 400, 450, FR 350, 450 5

Fastener Thread For component Torque Remarkssize Nm lbf.ft

Spline screw IS-M6x25 Clamp/loop handle 4.5 3.3 3)Spline screw IS-M6x25 Support/drive tube 6.0 4.4 1) 4) 6)Spline screw IS-M6x35 Clamp moldings/support block

(handle support/bike handle) 4.5 3.3 3)M8 Carrier 24.0 17.7

Spline screw IS-M6x18 Clutch shoe/carrier 12.0 8.8M8 Flywheel 32.0 23.6M10 Decompression valve 14.0 10.3 1) 2) 4) 5)M14x1.25 Spark plug 20.0 15.0

Screw plug M11x10 Gearhead 8.5 6.3Spline screw IS-M5x14 Filter cover/filter housing 6.0 4.4 1) 2)Plastoform screw IS-P4x16 Control handle/handle moldings 1.0 0.75Collar screw IS-P3.5x10.6 Detent spring/slide control

(bike handle) 1.1 0.80 1) 3) 4)Nut M12x1.5 L Cutting tool 25.0 18.5Spline screw IS-M5x16 Cutting tool deflector/gearhead 4.3 3.2Spline screw IS-M6x14 Spring/support plate 10.0 7.5 2) 5)Spline screw IS-M6x25 Housing/shaft clamp screw 4.5 3.3 2) 5)Spline screw IS-M6x14 Bearing housing/support frame 10.0 7.5 2) 5)Spline screw IS-M10x20 Support plate/ball bearing/

support frame 20.0 15.0 2) 5)

Use the following procedure to fit a DG or P screw in an existing thread: Place the DG or P 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.

1) FS 400/4502) FR 4503) FS 120/2004) FS 300/3505) FR 3506) with washerNote: Power screwdriver speed settings for polymer: Plastoform screws max. 600 rpm

DG screws max. 500 rpm

6 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Removal

Troubleshooting chart - see"Standard Repairs, Trouble-shooting" handbook.

- Remove clutch housing -see 9.1 or 11.2.

All models Inspect clutch drum. There

should be no scores or signs ofexcessive wear.

Important: If there are signs ofserious wear on the insidediameter, fit a new clutch drum -see 11.2.

- Remove the shroud - see 4.1.

- Pull off the spark plug boot.

- Unscrew the spark plug.

FS 120...350, FR 350 Fit locking strip (1)

0000 893 5903.

FS 400/450, FR 450 Fit locking strip (1)

4221 893 5900.

Take out screws (1). Remove cover (2).

Remove clutch shoes withbushings.

Take bushings out of the clutchshoes.

Twist the clutch shoes anddetach the springs.

Important: Clutch shoes andsprings must always be replacedin pairs.

3. CLUTCH3.1 Removing and Installing

250R

A001

1

VA25

0RA0

02

1

VA25

0RA0

04

11

2

VA

250R

A003

VA

250R

A005

VA25

0RA2

30VA

250R

A229

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 7

Installation

Fit clutch shoes with springs andbushings so that the arrows pointcounterclockwise.

Fit cover in position.

Insert screws and tighten downto 12 Nm (8.8 lbf.ft).

- Pull locking strip out of cylinder.

- Fit spark plug and tighten downto 20 Nm (15 lbf.ft).

Important: If the spark plugcomes with a separate terminalnut, always fit the nut on thethread and tighten it downsecurely.

- Fit the boot on the spark plug.

- Fit the shroud - see 4.1.

- Fit clutch housing -see 9.1 or 11.2.

- Remove clutch - see 3.1.

Unscrew carrier from end ofcrankshaft.

Fit the carrier and tighten itdown to 24 Nm (17.7 lbf.ft).

- Install the clutch - see 3.1.

3.2 Clutch Carrier

250R

A232

VA25

0RA2

31VA

250R

A234

VA25

0RA2

35VA

250R

A233

VA

8 FS 120, 200, 300, 350, 400, 450, FR 350, 450


Spark arresting screen

FS 120...350, FR 350 Pull spark arresting screen out of

the muffler.

- Clean or replace spark arrestingscreen if necessary.

FS 400/450, FR 450 Take out the screw (1). Pull spark arresting screen (2)

out of the muffler.

- Clean or replace spark arrestingscreen if necessary.

- Tighten down screw to 2.5 Nm(1.8 lbf.ft).

Muffler

FS 400/450, FR 450- Remove air filter cover - see 8.1.

All models Remove screws from clutch

housing.

Take out screws (1). Press down the decompression

valve (2). Remove the shroud (3).

Take out the screws.

- Lift away the muffler.

Remove the gasket.

Reassemble in the reversesequence.

- Use a new gasket.

- Tighten down screws to 8.5 Nm(6.3 lbf.ft).

250R

A006

VA

250R

A011

VA

250R

A009

VA

250R

A012

VA

250R

A007

1 2

VA

1 250R

A010

1

32

VA

4. ENGINE4.1 Exhaust Muffler/Spark Arresting Screen

FS 120, 200, 300, 350, 400, 450, FR 350, 450 9

Defective oil seals, gaskets,cracks in castings or a faulty sea-ling ring between the carburetorhousing and cylinder are the usu-al causes of leaks. Such faults al-low air to enter the engine andthus upset the fuel-air mixture.

This makes adjustment of theprescribed idle speed difficult, ifnot impossible.

Moreover, the transition from idlespeed to part or full throttle is notsmooth.

The crankcase can be checkedthoroughly for leaks with the carbu-retor and crankcase tester and thevacuum pump.

- Remove the carburetor - see8.2.1 and 8.2.2.

- Set the piston to top dead center(T.D.C.). This can be checkedthrough the inlet port.

- Make sure the spark plug isproperly tightened down.

Slide a new gasket over thecarburetor studs.

Push the test flange (1)1128 850 4200 into position.

Fit and tighten down the nuts (2)firmly.

- Back off the muffler mountingscrews half-way.

Slide the sealing plate (1)0000 855 8106 between thegasket and cylinder exhaustport and retighten the mountingscrews moderately.

Note: The sealing plate mustcompletely fill the space betweenthe two mounting screws.

250R

A013

VA25

0RA0

14

21

2

VA

250R

A015

1

VA

4.2 Leakage Test 4.2.1 Preparations

10 FS 120, 200, 300, 350, 400, 450, FR 350, 450

- Carry out preparations -see 4.2.1.

Connect pressure hose of tester1106 850 2905 to nipple on testflange.

Close the vent screw (1) onthe rubber bulb.

- Use rubber bulb to pump air intothe crankcase until the gaugeindicates a pressure of 0.5 bar(7.25 psi). If this pressure re-mains constant for at least 20seconds, the crankcase or de-compression valve, if fitted, isairtight.

However, if the indicated pressu-re drops, the leak must belocated and the faulty partreplaced.

Note: To find the leak, coat thesuspect area with oil andpressurize the crankcase again.Bubbles will appear if a leak exists.

- If the decompression valve is notairtight, install a new one - see4.8.

- Repeat the pressure test.

- Carry out the vacuum test - see4.2.3.

- After finishing the test, open thevent screw and disconnect thehose.

- Remove the test flange.

- Slacken off the muffler mountingscrews.

- Pull out the sealing plate andtighten down the screws to8.5 Nm (6.3 lbf.ft).

- Install carburetor - see 8.2.1 or8.2.2.

Oil seals tend to fail when sub-jected to a vacuum, i.e. the sealinglip lifts away from the crankshaftduring the pistons induction strokebecause there is no internalcounterpressure.

An additional test can be carriedout with the vacuum pump todetect this kind of fault.

- Carry out preparations -see 4.2.1.

Connect the suction hose ofvacuum pump 0000 850 3501to test flange nipple.

Close vent screw (1) onpump cylinder.

Operate lever (2) until the gauge(3) indicates a vacuum of 0.5 bar(7.25 psi).

250R

A016

VA

250R

A017

VA

VA14

3RA0

46

1

250R

A016

VA25

0RA0

18

1

2

3VA

4.2.2 Pressure Test 4.2.3 Vacuum Test

FS 120, 200, 300, 350, 400, 450, FR 350, 450 11

Note: If the vacuum readingremains constant, or rises to nomore than 0.3 bar (4.25 psi) within20 seconds, it can be assumedthat the oil seals are in goodcondition.However, if the pressure continuesto rise (reduced vacuum in thecrankcase), the oil seals must bereplaced.

- After finishing the test, open thevent screw and disconnect thehose.

- Remove the test flange.

- Sacken off the muffler screws.

- Remove the sealing plate tightenscrews to 8.5 Nm (6.3 lbf.ft).

- Install carburetor - see 8.2.1 and8.2.2.

It is not necessary to disassemblethe complete engine to replace theoil seals.

The FS 200 engine is shown in theillustrations.

Starter side:

- Remove the flywheel - see 5.4.

- Tap the oil seal with a suitablepiece of pipe or a punch torelease it from its seat.

Apply the puller (1)5910 890 4400 (with No. 3.1jaws 0000 893 3706).

- Tension the arms.

- Pull out the oil seal.

Important: Take care not todamage crankshaft stub.

- Clean sealing surface with astandard solvent-based degrea-sant containing no chlorinated orhalogenated hydrocarbons - see13.2.

- Lubricate sealing lips of oil sealwith grease - see 13.2.

- Slide the oil seal, open sidefacing the crankcase, over theend of the crankshaft.

Use the press sleeve (1)4112 893 2401 to press it fullyhome.

- Install flywheel - see 5.4.

Clutch side:

- Remove carrier - see 3.2.

- Tap the oil seal with a suitablepiece of pipe or a punch torelease it from its seat.

Apply the puller (1)5910 890 4400 (with No. 3.1jaws 0000 893 3706).

- Tension the arms.

- Pull out the oil seal.

Important: Take care not to dama-ge crankshaft stub.

- Clean sealing surface with astandard solvent-based degrea-sant containing no chlorinated orhalogenated hydrocarbons - see13.2.

- Lubricate sealing lips of oil sealwith grease - see 13.2.

250R

A019

1

VA

250R

A020

VA

1

250R

A021

1

VA

4.3 Oil Seals

12 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Slip installing sleeve (1) 4112893 2400 over the end of thecrankshaft.

- Push the oil seal, open sidefacing the crankcase, over theinstalling sleeve and press ithome with the press sleeve.

Press home with press sleeve(1) 1118 893 2401.

- Remove the installing sleeve.

- Install carrier - see 3.2.

Always check and, if necessary,repair the fuel system, carburetor,air filter and ignition system beforelooking for faults on the engine.


- Remove the muffler - see 4.1.

- Remove the carburetor - see8.2.1 and 8.2.2.

Take out screws (1). Pull away the carburetor housing

(2).

FS 400/450, FR 450 Disconnect hose from fuel pump

and pull it out of the guide.

Take out screws (1). Pull away the carburetor hous-

ing (2), ease grommet out ofcarburetor housing and pull theextended throttle cable out of thehousing opening.

Assemble in the reversesequence.

Fit stub (1) on carburetor hou-sing in the sealing ring (2) andthrottle cable (3) in the retainer(4).

- Tighten down screws to 6 Nm(4.4 lbf.ft).

250R

A022

1

VA

250R

A025

VA

250R

A023

1

VA

250R

A024

2

11

VA

250R

A026

VA

1

12

250R

A027

3 4

2

1

VA

4.4 Exposing the Cylinder

FS 120, 200, 300, 350, 400, 450, FR 350, 450 13

FS 400/450, FR 450 Fit throttle cable (1) and grom-

met (2) in opening in carburetorhousing.

Insert stub (3) in the sealingring (4).

- Secure lug of extended throttlecable between the raised marksand tighten down the screwsto 6 Nm (4.4 lbf.ft).

- Preparations - see 4.4.

- Remove clutch housing -see 9.1 and 11.2.


- On FS 120...350, FR 350: Takeignition lead out of the retainerson the throttle cable holder.


- Unscrew the decompressionvalve, if fitted.

FS 400/450, FR 450 Take cable retainer out of

cylinder.

All models:Illustrations show theFS 200 engine.

Pull out the sealing ring.

Release and unscrew thefour cylinder base screws.

- Pull the cylinder off the piston.

- Inspect the cylinder and replaceit if necessary.

- If a new cylinder has to beinstalled, always fit the matchingpiston. New cylinders are onlyavailable with piston.

- Before removing the piston,decide whether or not the cranks-haft has to be removed as well.To remove the clutch and carrier,block the crankshaft by slidingthe wooden assembly blockbetween the piston and crank-case.

- Remove the cylinder gasket.

Ease the hookless snap ringsout of the grooves in the pistonbosses.

250R

A030

VA

250R

A028

4 3

1 2VA

250R

A029

VA

250R

A031

VA25

0RA0

32VA

4.5 Cylinder and Piston4.5.1 Removal

14 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Now use the assembly drift (2)1110 893 4700 to push the pi-ston pin (1) out of the piston.

Note: If the piston pin is stuck, tapthe end of the drift lightly with ahammer if necessary. Hold thepiston steady during this processto ensure that no jolts are trans-mitted to the connecting rod.

- Remove piston and take theneedle cage out of the connec-ting rod.

Inspect piston rings and replaceif necessary - see 4.6.

Thoroughly clean the gasketseating surface (1).

Check that adapter sleeves (2)are in place. Fit them if necessa-ry.

Lubricate the needle cage (3)with oil and fit it in the connectingrod.

To simplify assembly, heat the pi-ston and slip it over the connec-ting rod.

Installed position of piston:1 = Marking2 = Flywheel

Push the assembly drift, smalldiameter first, through the pistonand small end (needle cage) andline up the piston.

Fit the piston pin (1) on theassembly drift (2) and slide itinto the piston (the pin slideshome easily if the piston is hot).

Modify sleeve of installing tool5910 890 2210 as shown in dra-wing.a = 30 degreesb = 10 mm

250R

A033

1 2

VA

250R

A035

1 2

2

3

VA25

0RA0

37

21

VA

250R

A034

VA

250R

A038

VA25

0RA0

39

1 2

VA25

0RA0

57

ba

VA

4.5.2 Installation

FS 120, 200, 300, 350, 400, 450, FR 350, 450 15

Use installing tool (1)5910 890 2208 to fit the snaprings.

Note: For instructions on how touse the installing tool see"Standard Repairs, Trouble-shooting" handbook.

Fit new cylinder gasket on thecrankcase.

Lubricate piston and piston ringswith oil. Rest piston (1) onwooden assembly block (2)1108 893 4800.

Position the piston rings so thatthe radii at the ring gap meet atthe fixing pin in the piston groovewhen the rings are compressed.

Use the clamping strap (1)0000 893 2600 to compress thepiston rings around the pistonand check that the piston ringsare correctly positioned.

- Lubricate the inside of thecylinder with oil and line it up sothat it is positioned as it will be inthe installed condition. It is im-portant to observe this point asthe piston rings might otherwisebreak.

Slide the cylinder over the piston- the clamping strap is pusheddownward as the piston ringsslip into the cylinder.

- Remove the clamping strapand wooden assembly block.

- Line up the cylinder and gasket.

Use socket (1) 0812 542 2104to tighten down cylinder basescrews to 8.5 Nm (6.3 lbf.ft).

Assemble all other parts in thereverse sequence.

250R

A042

VA25

0RA0

41

1

2 VA

250R

A040

VA25

0RA0

36

1

VA

250R

A043

1

VA

250R

A044

VA25

0RA0

45

1

VA

16 FS 120, 200, 300, 350, 400, 450, FR 350, 450

- Remove the piston - see 4.5.1.

Note: The piston must be re-moved to make sure that noresidue can fall into the crankcasewhen installing the piston ringsand cleaning their grooves.

Illustrations show pistonin model FS 200.

- Remove rings from piston.

Use a piece of old piston ring toscrape the grooves clean.

Install the new piston rings in thegrooves so that the radii (1) facethe fixing pin (2).

- Install the piston - see 4.5.2.

- Remove the ignition module -see 5.3.2 and 5.3.3.

- Remove the fuel tank - see 8.5.

- Remove the cylinder - see 4.5.1.

All models Take out screw (1). Remove top of cable guide (2).

FS 120...350, FR 350

Take throttle cable (1) out ofbase of guide (2).

Take short circuit wire (3) out ofbase of guide and remove it fromthe retainers (4).

FS 400/450, FR 450 Remove short circuit wire from

the retainers.

Ease the grommets out of thehousing and pull out the shortcircuit wire.

All models Pull the base of the guide

off the housing.

- Remove the carrier - see 3.2.

250R

A049

1

3

2

4

VA

250R

A046

VA

250R

A048

2

1

VA

2

1

250R

A047

1

VA

250R

A050

VA25

0RA0

51VA

250R

A052

VA

4.6 Piston Rings 4.7 Crankcase4.7.1 Removing Crankshaft

FS 120, 200, 300, 350, 400, 450, FR 350, 450 17

- Remove the flywheel - see 5.4.

- Remove the piston - see 4.5.1.


Place extension (1) 4116 8941000 on crankshaft stub at clutchside of crankcase.

Back off spindle (left-hand thre-ad) of ZS installing tool (1) 5910890 2220 a little.

Hold ZS installing tool againstclutch side of crankcase so thatthe notch marked "16" is at thebottom.

Insert M6x20 screws (2) in holesmarked "17" and tighten themdown against the drilled plate.

Note: ZS installing tools withoutholes "16", "17" and "18" andnotches "16" and "17" can bemodified as shown in theillustration.

Holes "16" and "18" are needed atthe starter side of the crankcase.

The illustration shows the under-side of the drilled plate.

250R

A056

VA25

0RA0

62

1

VA

17

250R

A063

2 17

16

2

1

VA

41.2

533

.85

9.7

26.8

52.

25

250R

A219

17.3

33.3 38.0

33.620.6

32.25

22.5

41.6

25.533.7

20.1

17.6

512

.6

24.7

5

17

19.9

18

16

18

1616

17

18

16

18

17

16

1

2.5

15.5

16 + 18 = 5,517 = 6,5

VA

18 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Rotate spindle (1) counterclock-wise until the crankshaft comesout of the ball bearing. The twohalves of the crankcase areseparated in this process.

Puller (1) 4119 890 4600 can beused in place of the ZS installingtool. It is mounted to the clutchside of the crankcase wit M6x20screws (2).

Turn thrust bolt (3) clockwiseuntil the crankshaft is releasedfrom the ball bearing.

FS 120...350, FR 350- Back off spindle (left-hand thre-

ad) of ZS installing tool5910 890 2220 a little.

Place extension (1) 4116 8941000 on crankshat stub andsleeve (2) 1123 851 8300 onbores at starter side of crank-case.

Hold ZS installing tool (1)5910 890 2220 against starterside of crankcase so that thenotch marked "16" is at thebottom.

Insert screws (1) 9022 341 1190(from ZS installing tool kit) inholes marked "16", fit washers atother side and screw on nuts.

FS 400/450, FR 450- Hold ZS installing tool against

starter side of crankcase so thatthe notch marked "17" is at thebottom.

- Insert M5x60 screws in holesmarked "18", fit washers at otherside and screw on nuts.

All models

Rotate spindle (1) counterclock-wise until the crankshaft comesout of the ball bearing.

The crankshaft (1), connectingrod (2) and needle bearing forman inseparable unit. It mustalways be replaced as a com-plete unit.

250R

A061

1

VA25

0RA0

65

1

32

2

VA

250R

A058

2

1

2

VA

16

250R

A059

1

VA25

0RA0

60

116

1616

16

1

1

1

VA

250R

A064

1

VA25

0RA0

66

2

1

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 19

- When fitting a replacementcrankshaft always install new oilseals and ball bearings.

Carefully knock the oil seals outof the crankcase.

Use press arbor (1) 4119 8937200 to remove ball bearing.

Use press arbor (1) 4119 8937200 to remove ball bearing.

- Inspect both halves of the crank-case for cracks and replace if ne-cessary.

Each half of the crankcase maybe replaced separately.

New crankcases come withfactory-installed ball bearings.

If the original crankcase is usedagain, remove the gasket residueand clean the mating surfaces -they must be cleaned verythoroughly to ensure a perfectseal.

Check that bushings are in posi-tion. If necessary, drive bushingsinto the crankcase.

- Heat area of bearing seat onstarter side of crankcase toapprox. 120C (250F).

Fit ball bearing in crankcase byhand and push it home as far asstop.

Note: This operation must becarried out very quickly becausethe bearing absorbs heat immedi-ately and begins to expand.

If it is not possible to heat thestarter side of the crankcase,use press arbor (1) 4119 8937200 to press in the ball bearingas far as stop.

- Heat area of bearing seat onclutch side of crankcase toapprox. 120C (250F).

250R

A067

VA25

0RA0

68

1

VA25

0RA0

69VA

1

250R

A071

VA25

0RA0

70VA

250R

A071

VA

4.7.2 Installing Crankshaft

20 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Fit ball bearing in crankcase byhand and push it home as far asstop.

Note: This operation must becarried out very quickly becausethe bearing absorbs heat immedi-ately and begins to expand.

If it is not possible to heat theclutch side of the crankcase, usepress arbor (1) 4119 893 7200 topress in the ball bearing as faras stop.

Position the straight stub of thecrankshaft in the bearing at theclutch side of the crankcase.

Screw spindle (1) of installingtool 5910 890 2202 fully into thesleeve (2) (left-hand thread).

Hold the crankshaft steady andscrew the spindle (1) clockwiseonto the stub (2) as far as stop.

Hold the spindle steady androtate sleeve counterclockwiseuntil it butts against the ballbearing.

Hold the sleeve steady androtate spindle clockwise until thecrankshaft butts against the ballbearing.

Important: During this processthe connecting rod (withoutpiston) must point towards thecylinder flange.

- Hold the crankshaft steady andunscrew spindle from the stub.

- Apply a thin coating of sealant tocrankcase mating face - see13.2.

Important: Follow manufacturersinstructions.

250R

A073

VA

250R

A077

VA

250R

A075

VA39

2RA0

44

2 1

VA

250R

A078

VA

250R

A074

1

VA

250R

A076

21

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 21

Fit starter side of crankcase overthe crankshaft stub.

Hold crankshaft steady andscrew the spindle (1) clockwiseonto the stub (2) as far as stop.

Hold the spindle steady androtate sleeve counterclockwiseuntil it butts against the ballbearing.

Hold the sleeve steady androtate spindle clockwise until thetwo halves of the crankcase aretogether.

- Remove the installing tool.

Insert screws and use socket (1)0812 542 2104 to tighten themdown to 8.5 Nm (6.3 lbf.ft).

- Lubricate sealing lips of oil sealswith grease - see 13.2.

Fit installing sleeve (1) 4112 8932400 over the clutch end of thecrankshaft.

- Slide the oil seal, open sidefacing the crankcase, over theinstalling sleeve.


- Remove the installing sleeve.

- Slide the oil seal, open sidefacing the crankcase, over thestarter end of the crankshaft.


Assemble as other parts in thereverse sequence.

- Adjust throttle cable - see 7.5.2.

250R

A082

VA

250R

A079

VA

250R

A085

1

VA

250R

A080

21

VA

250R

A083

1

VA

250R

A086

1

VA

250R

A084

1

VA

250R

A081

VA

22 FS 120, 200, 300, 350, 400, 450, FR 350, 450


Use standard commercial long-reach 13 mm socket to unscrewthe decompression valve.

- Install new decompression valveand tighten down to 14 Nm(10.3 lbf.ft).

- Fit the shroud.

Warning! Exercise extremecaution when carrying outmaintenance and repair work onthe ignition system. The highvoltages which occur can causeserious or even fatal accidents!

Troubleshooting on the ignitionsystem should always begin at thespark plug. See "Standard Re-pairs, Troubleshooting" handbook.

Note: The electronic (breakerless)ignition system basically consistsof an ignition module (1) andflywheel (2).The illustration shows the FS 200.



- On FS 400/450, FR 450, takecable holder off the cylinder.

Use pliers to grip the leg springand pull it out of the spark plugboot.

- Unhook the leg spring from theignition lead.

- Pull spark plug boot off theignition lead.

- Coat end of the ignition lead(about 20 mm/3/4") with oil.

- Fit spark plug boot over theignition lead.

- Use pliers to grip the end of theignition lead inside the sparkplug boot and pull it out.

4.8 Decompression Valve 5. IGNITION SYSTEM 5.1 Spark Plug Boot

250R

A091

VA

250R

A087

VA

1

2 250R

A088

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 23

Pinch hook of leg spring into thecenter of the lead, i.e. about10 mm (3/8") from the end ofthe lead.

Pull the lead back into theboot so that the leg springlocates properly inside it.

Important: If the spark plugcomes with a separate terminalnut, always fit the nut on thethread and tighten it downsecurely.

- On FS 400/450, FR 450, attachthe cable retainer to the cylinder.

- Fit the boot on the spark plug.


- Remove the ignition module -see 5.3.3.

Remove spark plug boot (1) -see 5.1.

Pull off the cable retainer (2).

Remove the retainer.

Pull rubber boot (1) off the highvoltage output.

Unscrew the ignition lead fromthe contact pin and pull it out ofthe high voltage output.

5.2 Ignition Lead(FS 400/450, FR 450)

250R

A089

VA

250R

A092

2 1

VA

250R

A090

VA

250R

A094

1

VAVA

250R

A008

250R

A053

VA

24 FS 120, 200, 300, 350, 400, 450, FR 350, 450

- Slip the rubber boot off theignition lead.

- Cut new ignition lead to length(see parts list or cut to samelength as old lead).

Use a pointed tool (awl or gimlet)to pierce the center of theignition lead that is to be scre-wed into the module.

- Slip the rubber boot over thelead.

- Pack the high voltage output withSTIHL multipurpose grease - see13.2.

Important: Do not use graphitegrease (Molykote) or siliconeinsulating paste for this job.- Screw home the ignition lead.

- Fit rubber boot on the highvoltage output.

- Fit cable retainer and spark plugboot.

- Fit the ignition module - see5.3.3.

The ignition module accommo-dates all the components requiredto control ignition timing.

FS 120...350, FR 350There are two electrical connec-tions on the coil body:

1. the high voltage output (1) withignition lead (2)

2. the connector tag (3) for theshort circuit wire

A vibration damping pad is bondedto the side of the ignition module.

FS 400/450, FR 450There are two electrical connec-tions on the coil body:

1. the high voltage output (1)2. the connector tag (2) for the

short circuit wire

Accurate testing of the ignitionmodule is only possible withsophisticated test equipment. Forthis reason it is only necessary tocarry out a spark test in the work-shop. A new ignition module mustbe installed if no ignition spark isobtained (after checking thatwiring and stop switch are in goodcondition).

5.3 Ignition Module

250R

A095

1

2

VA

338R

A142

VA

250R

A054

2 1

3

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 25

Ignition timing is not adjustable.Since there is no mechanical wearin these systems, ignition timingcannot get out of adjustment. How-ever, an internal fault in the circuitcan alter the switching point insuch a way that a spark test willstill show the system to be in orderalthough timing is outside thepermissible tolerance. This willimpair engine starting and runningbehavior.


- Pull the boot off the spark plug.

- Remove the fan housing - see6.2.

- Remove clutch housing -see 9.1.

Remove ignition lead from theretainers.

Pull short circuit wire connector(1) off tag on ignition module.


- Remove the ignition module.

- Remove the spark plug boot -see 5.1.

Note: The ignition lead is moldedto the ignition module.

Important: Before installing a newignition module, make sure areafor vibration damping pad is freefrom grease, dirt and moisture.

- Peel the backing off the newvibration damping pad.

Place the pad on the ignitionmodule and apply firm anduniform pressure.

250R

A098

1

2

3 VA

250R

A099

VA

250R

A096

VA

5.3.1 Ignition Timing 5.3.2 Removing and Installing (FS 120...350, FR 350)

250R

A097

VA

26 FS 120, 200, 300, 350, 400, 450, FR 350, 450

- Place the module in position,insert the screws but do nottighten them down yet.

- Check that ignition lead isproperly seated in grommet.

Slide the setting gauge (1)1127 890 6400 between thearms of the ignition module andthe flywheel magnet poles.

- Press the ignition moduleagainst the flywheel and tightendown the mounting screws to atorque of 4.5 Nm (3.3 lbf.ft).

Reassemble all other parts in thereverse sequence.



Pull boot (1) off the spark plug. Pull cable retainer (2) out of

cylinder.

Take ignition lead out of guide.


Lift ignition module away slightlyand disconnect short circuit wirefrom ignition module.

- Remove the ignition lead - see5.2.

- Connect the short circuit wire,place the module in position,insert the screws but do nottighten them down yet.

250R

A103

VA25

0RA1

04VA

250R

A102

VA

5.3.3 Removing and Installing (FS 400/450, FR 450)

250R

A101

1

2

VA

250R

A100

1

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 27

Secure cable retainer (1) withouter screw.

Slide the setting gauge (2)1127 890 6400 between thearms of the ignition module andthe flywheel magnet poles.

- Press the ignition moduleagainst the flywheel and tightendown the mounting screws to atorque of 6.0 Nm (4.4 lbf.ft).

Reassemble all other parts in thereverse sequence.

Removing the flywheel:




FS 120...350, FR 350 Fit locking strip (1)

0000 893 5903.

FS 400/450, FR 450- Fit locking strip

4221 893 5900.

All models

Unscrew the flywheel nut.

- Pull off the flywheel.

Note: If the flywheel cannot beremoved by hand, screw on thepuller (1) 4133 893 0800 and tapits end to release the flywheel.Unscrew the puller.

Inspect the flywheel (1) andmagnet poles (2). If you find anydamage, install a new flywheel.

Installing the flywheel:

Important: Clean the stub of thecrankshaft and the flywheel hubbore with a standard commercial,solvent-based degreasant whichcontains no chlorinated orhalogenated hydrocarbons - see13.2.

- Fit the flywheel.

Note: Check position of slot.

Assemble all other parts in thereverse sequence.

- Fit flywheel nut. Tighten nut onFS 120 to 24 Nm (17.7 lbf.ft).Tighten nut on all other modelsto 32 Nm (23.6 lbf.ft).

5.4 Flywheel

250R

A110

2

1

VA

250R

A106

1

VA

250R

A109

1

VA

250R

A107

VA

2 250RA

105

1

VA

28 FS 120, 200, 300, 350, 400, 450, FR 350, 450

- Remove the ignition module -see 5.3.2 and 5.3.3.


FS 120...350, FR 350

Pull short circuit wire out ofgrommet.

Remove short circuit wire fromretainers.

FS 400/450, FR 450- Remove the fuel tank - see 8.5.

- Remove the muffler - see 4.1.

Push out the outer grommet (1). Pull short circuit wire out of

housing bore and removegrommet.

Push out the grommet (1). Pull short circuit wire (2) out of

housing bore, remove it fromthe retainers and pull off thegrommet.

All models Take out the screw (1). Remove top of cable guide (2).

Lift the throttle cable (1) a little. Remove short circuit wire

connector (2) from base of cableguide.


- Check and adjust throttlecable - see 7.5.2.

5.5 Short Circuit Wire

250R

A113

1

VA

250R

A115

VA

1 2

250R

A1141

2

VA

250R

A111

VA

250R

A116

2 1

VA

250R

A112

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 29

If the action of the starter ropebecomes very stiff and the roperewinds very slowly or not com-pletely, it can be assumed thatthe starter mechanism is in orderbut plugged with dirt. At very lowoutside temperatures the lubri-cating oil on the rewind spring maythicken and cause the springwindings to stick together. Thishas a detrimental effect on thefunction of the starter mechanism.In such a case it is sufficient toapply a few drops of paraffin(kerosine) to the rewind spring.Then carefully pull out the starterrope several times and allow it torewind until its normal smoothaction is restored.

If clogged with dirt or pitch, theentire starter mechanism, inclu-ding the rewind spring, must be re-moved and disassembled. Takespecial care when removing thespring.

Wash all parts in paraffin or whitespirit.

Lubricate the rewind spring andstarter post with STIHL speciallubricant, see 13.2, beforeinstalling.



Remove fan housing with rewindstarter.

- Remove the rope rotor - see"Standard Repairs, Trouble-shooting" handbook.

Take out the screw and removeany remaining pieces of springfrom the fan housing.

Note: The replacement springcomes ready for installation and issecured with a washer.

- It should be lubricated with a fewdrops of STIHL special lubricantbefore installation - see 13.2.

The washer slips off the rewindspring as it is pushed into the fanhousing. Engage the outerspring loop in the recess in thefan housing at the same time.

Caution: The rewind spring maypop out and uncoil duringinstallation.

- If the rewind spring has poppedout, refit it as follows:

250R

A119

VA

250R

A117

VA25

0RA1

18VA

6. REWIND STARTER 6.2 Rewind Spring6.1 General 6.2.1 Replacing

30 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Engage outer spring loop in therecess and refit rewind spring infan housing in the counterclock-wise direction, starting outsideand working inwards.

Check the position of theinner spring loop. It should be2 mm (0.08") away from the hub.

- Fit screw and tighten it down to1.5 Nm (1.1 lbf.ft).

- Install the rope rotor - see"Standard Repairs, Troubleshoo-ting" handbook.

- Tension the rewind spring - see6.2.2.

Make a loop in the starter rope.

Grip the rope close to the rotorand use it to turn the rope rotorsix full turns counterclockwise.

Hold the rope rotor steady.

Pull out the rope with the startergrip and straighten it out.

- Hold the starter grip firmly tokeep the rope tensioned.

- Let go of the rope rotor andslowly release the starter ropeso that it can rewind properly.

Note: The rewind spring is cor-rectly tensioned when the startergrip sits firmly in the rope guidebush without drooping to one side.If this is not the case, tension thespring by one additional turn.

When the starter rope is fullyextended, it must still be possibleto rotate the rope rotor at leastanother half turn before maximumspring tension is reached. If this isnot the case, pull the rope out,hold the rope rotor steady andtake off one turn of the rope.

Do not overtension the rewindspring as this will cause it tobreak.

- Fit fan housing, insert screwsand tighten down to 6.0 Nm(4.4 lbf.ft).

VA25

0RA1

21A25

0RA1

23VA

250R

A125

VA

250R

A122

VA

250R

A120

VA

250R

A124

VA

6.2.2 Tensioning

FS 120, 200, 300, 350, 400, 450, FR 350, 450 31

- Remove fan housing with rewindstarter - see 6.2.

Starter rope

- Remove rope rotor - see"Standard Repairs, Trouble-shooting" handbook.

- Remove the starter rope fromthe rotor.

Pry cap out of starter grip.

- Pull rope out of starter grip.

- On FR 350/450, slip tube(75 mm/2.95") over the starterrope.

Thread end of new starter ropethrough the underside of the star-ter grip.

- Secure end of rope with a simpleoverhand knot.

Pull the rope back to locate theknot in the starter grip.

- Push cap into starter grip.- Secure starter rope to rope rotor.- Install the rope rotor.

Starter gripThe starter grip is supplied withstarter rope.

- Remove the rope rotor - see"Standard Repairs, Trouble-shooting" handbook.

- Pull the knot out of the recess inthe rope rotor.

- Undo the knot and pull the ropeout of the rotor and fan housing.

- On FR 350/450, slip tube(75 mm/2.95") over the starterrope.

Thread the starter rope0000 195 8200 through the gui-de bush from outside thefan housing.

Thread rope through the hole inthe side of the rotor.

- Secure the starter rope with asimple overhand knot.

Pull the rope back into thr rotorso that the knot locates in therecess.

- Install the rope rotor - see"Standard Repairs, Trouble-shooting" handbook.

- Tension the rewind spring - see6.2.2.

- Fit fan housing with rewindstarter - see 6.2.2.

VA36

2RA0

9725

0RA1

26VA

VA25

0RA1

27

VA36

2RA0

95VA

362R

A096

VA25

0RA1

28

6.3 Starter Rope/Starter Grip (ElastoStart)

32 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Take out screw and washer.

- Pull off the control handle.

Warning: To avoid risk of electricshock, do not start the unit whilethe control handle is open.

Use screwdriver (1) 5910 8902301 to take out the screws.

- Separate the two halves of thehandle.

Lift the interlock lever (1) slightlyand turn it to one side until thetorsion spring (2) is relaxed.

Pull the interlock lever off thepeg.

Remove the torsion spring.

Take the throttle trigger (1) withtorsion spring (2) and throttlecable (3) off the peg.

Disconnect throttle cable fromtrigger.


Attach the throttle cable, thenposition torsion spring as shownand push its long arm into theslot.

The interlock lever must bebehind the throttle trigger.

Check correct positions ofthrottle cable (1), contact spring(2), protective tube (3) andinsulator (4).

7. THROTTLE CONTROL7.1 Throttle Trigger/Interlock Lever (Bike Handle)

FS 120, 200, 300, 350, 400, 450, FR 350, 450 33

- Remove the throttle trigger - see7.1.

Lift contact spring (1) a little andremove the throttle cable (2).

Remove spring from seats (1)and peg (2).

Remove contact spring from peg(1) and collar screw (2).

Take out slide controls collarscrew (1).

Remove detent spring (2).

Pull slide control out of handlemolding.


- Engage contact spring correctlyin groove of collar screw.

FR 350/450 Use screwdriver (1) 5910 890

2301 to remove screw.

Push guard (2) forward.

All models

Warning: To avoid risk of electricshock, do not start the unit whilethe control handle is open.

Use screwdriver (1) 5910 8902301 to take out the screws.

- Remove handle molding.

Remove torsion spring.

7.2 Contact Springs/Detent Spring in Control Handle 7.3 Throttle Trigger/Interlock(Bike Handle) Lever (Loop Handle)

34 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Pull throttle trigger (1) withthrottle cable (2) off the peg.

Disconnect throttle cable fromtrigger.

Lift contact spring (1) a little andremove the throttle cable (2).

Pull interlock lever with contactspring off the peg.

Remove contact spring frominterlock lever.


Check positions of throttle cable(1), contact spring (2), protectivetube (3) and insulator (4).

- Tighten screws to 1.0 Nm(0.75 lbf.ft).

- Remove the interlock lever - see7.3.

Pull slide control off the handlemolding.

Remove screws from clamps.

- Take handle molding off the dri-ve tube.

Remove torsion spring from peg.

7.4 Slide Control(Loop Handle)

FS 120, 200, 300, 350, 400, 450, FR 350, 450 35

Assemble in the reverse sequence.

- Tighten clamp screws to 2 Nm(1.5 lbf.ft).

The groove (1) in the slidecontrol must engage over theouter edge (2) of the handlemolding.

The torsion spring (3) mustengage the recess (4) in theslide control.

On FR 350/450, the distance "a"between the control handle andhousing must be 20 mm (0.8").

All models- Remove the shroud - see 4.1.


- Remove the air filter - see 8.1.

- Take throttle cable off the con-tact spring - see 7.2 and 7.3.

Note: On FS 120...350, FR 350,remove spark plug boot and takeignition lead out of retainers on topand base of cable guide.

Take out the screw (1). Remove top of cable guide (2).

FS 120...350, FR 350 Remove screw (1) from

extended throttle cable (2).

Disconnect throttle cable nipple(1) from slotted pin (2) on throttlelever.

Take throttle cable (1) out ofbase of cable guide (2) andretainer (3) on carburetorhousing.

FS 400/450, FR 450- Remove the air filter housing -

see 8.2.2.

Remove screw (1) fromextended throttle cable (2).

7.5 Throttle Cable7.5.1 Replacing

250R

A143

12

VA25

0RA1

44

1 2 3

VA

250R

A141

VA

1 2

250R

A145

1 2

VA

250R

A142

1 2

VA

250R

A237

a

VA

36 FS 120, 200, 300, 350, 400, 450, FR 350, 450


Pull grommet out of carburetorhousing.

Take throttle cable (1) out ofbase of cable guide (2) and pullit out of opening (3) in carburetorhousing.


FS 400/450, FR 450 Make sure grommet is properly

located in the carburetor housing.

- Secure lug between the raisedmarks.

FS 120...350, FR 350- Place lug and extended throttle

cable in the corner of the filterhousing.

- Tighten screw of extendedthrottle cable to 6.0 Nm(4.4 lbf.ft).

- Adjust throttle cable - see 7.5.2.

Throttle lever (1) must buttagainst the stop on the carbure-tor cover (2) when throttle triggeris squeezed (full throttle).

On carburetors with an idlespeed screw: Throttle lever mustbutt against the idle speed screwwhen the trigger is in the idleposition.

Note: The filter housing is notshown in the illustration.

Adjustment is effected by movingthe throttle cable in the holder.


- On FS 300...450, remove coverfrom AV housing - see 9.2.

- Check correct setting of idlespeed screw (if fitted).

Important: Note adjustment rangeof idle speed screw.

7.5.2 Adjusting

250R

A149

VA

250R

A146

1

2

VA25

0RA1

47

2 1

VA

325

0RA1

48

2

1

VA

250R

A239

VA

250R

A238

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 37

Release screw (1) and pullthrottle cable (2) out a little.

Note: The throttle lever movestowards the carburetor cover.

- Squeeze throttle trigger all theway (full throttle position), holdit steady and tighten screw to6.0 Nm (4.4 lbf.ft).

- Release throttle trigger (idleposition). The throttle lever mustbutt against the idle speedscrew, if fitted.

- On FS 300...450, fit cover on AVhousing.

- Fit the shroud.

Dirty and clogged air filters reduceengine power, increase fuelconsumption and make startingmore difficult.

The air filter must be cleanedwhen there is a noticeable lossof engine power.

- Close the choke shutter.

- Clean away any loose dirt fromaround the filter and filter cover.

FS 120...350, FR 350

Press down the tab.

Push the filter cover downwardsand take it off the lower lugs onthe filter housing.

FS 400/450, FR 450 Take out screw (1).

Swing the filter cover (2)forwards and take it off the lowerlugs on the filter housing.

All models Remove the filter.

- If the filter is heavily loaded withdirt or damaged, fit a new one.

- Fit filter in the housing.

- Position filter cover so that itlocates properly in the lower lugs.

- On FS 400/450, FR 450:Tighten screw to 3.0 Nm(2.2 lbf.ft).

250R

A151

VA

250R

A153

VA

8. FUEL SYSTEM8.1 Air Filter

250R

A152

12

VA

250R

A150

1 2VA

38 FS 120, 200, 300, 350, 400, 450, FR 350, 450

FS 120...350, FR 350


Important: In the event of troublewith the carburetor or the fuelsupply system, always check andclean the tank vent - see 8.3.


- Remove the air filter - see 8.1.

Take out screw (1) of extendedthrottle cable.

Pry choke knob (2) out of filterhousing and pull it off the chokeshaft.

Take fuel hose out of retainer infilter housing.

Disconnect fuel hoses frommanual fuel pump.

Unscrew the nuts.

Remove the filter housing andpull stub out of grommet at thesame time.

Check heat shield (1). If necessa-ry, push out the grommet (2) andremove the heat shield.


Pull the fuel hose (3) off theelbow connector on the carbure-tor.

Pull carburetor off the studs.

- If necessary, pull fuel hose offcarburetor.

250R

A156

VA

250R

A160

3

2

1

VA

250R

A157

VA

250R

A161

VA

250R

A158

VA

250R

A159

2 1

VA

8.2 Carburetor8.2.1 Removing and Installing

250R

A155

VA25

0RA1

54

1

2

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 39

Remove the gasket.


- Use a new gasket.

- Tighten down nuts on filterhousing to 3.5 Nm (2.6 lbf.ft).

- Tighten down screw on extendedthrottle cable to 6.0 Nm(4.4 lbf.ft).

FS 400/450, FR 450


Take out screw (1). Unscrew the nuts (2).

Remove the filter housing andpull stub out of grommet at thesame time.

Disconnect fuel hose fromconnector.

Pry choke knob out of carburetorhousing and pull it off the chokeshaft.


Disconnect fuel hose (3)from carburetor.

Pull carburetor off the studs.

8.2.2 Removing and Installing

250R

A166

VA

250R

A165

VA25

0RA1

63

1

2 2

VA25

0RA1

64VA

250R

A167

3

1

2

VA

250R

A013

VA

250R

A168

VA

40 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Remove the gasket.


- Use a new gasket.

- Tighten down nuts on filterhousing to 3.5 Nm (2.6 lbf.ft).

- Tighten down screw on filter hou-sing to 6.0 Nm (4.4 lbf.ft).

The carburetor can be tested forleaks with the carburetor andcrankcase tester 1106 850 2905.

FS 400/450, FR 450- Remove the shroud - see 4.1.

Pull fuel hose off carburetorselbow connector.

FS 120...350, FR 350- Remove the carburetor - see

8.2.1.

Fit fuel hose (1) 1110 141 8600on nipple (2) 0000 855 9200.

Push the fuel hose with nippleonto the carburetor elbowconnector.

Push the nipple into the testerspressure hose.

Close the vent screw (1) on therubber bulb (2) and pump air intothe carburetor until the pressuregauge (3) shows a reading ofapprox. 0.8 bar (11.5 psi).

250R

A170

VA

250R

A172

VA

VA14

3RA1

72

2 125

0RA1

71VA

8.2.3 Leakage Test

250R

A173

3

2

1

VA

250R

A169

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 41

If this pressure remains constant,the carburetor is airtight. However,if it drops, there are two possiblecauses:

1. The inlet needle is not sealing(foreign matter in valve seat orsealing cone of inlet needle isdamaged or inlet control leversticking).

2. The metering diaphragm isdamaged.

In either case the carburetor mustbe removed and serviced - see"Carburetor" handbook.

- After completing test, open thevent screw and pull the fuel hoseoff the elbow connector.

- Install the carburetor - see 8.2.1.

FS 400/450, FR 450- Push the fuel hose onto the

elbow connector.


Standard setting

If the carburetor has to beadjusted from scratch, first carryout the standard setting.

- Carefully screw in both adjustingscrews clockwise until they arehard against their seats.

Now make the following adjust-ments:

H = Open high speed screw (1)one full turn

L = Open low speed screw (2)one full turn

A slight correction to this settingmay be necessary at high altitudes(mountains) or near sea level. Usethe following procedure:

- Mount approved cutting tool.

- Check the air filter, replace ifnecessary.

- Check spark arresting screen,clean or replace as necessary.

- Start the engine and allow it towarm up.

Turn high speed screw (H)clockwise for leaner mixture athigh altutude,or counterclockwise for richermixture at sea level.

Turn screw slowly and carefully slight changes have a noticeableeffect on engine running behavior.

Adjusting idle speedEngine stops while idling:

- Carry out standard setting.

Turn the idle speed screw (LA)clockwise until cutting tool beginsto rotate, and then turn screw backone half turn.

Turn the idle speed screw (LD)clockwise until engine runssmoothly cutting tool must notrotate.

Cutting tool rotates whileengine is idling:

- Carry out standard setting.

Turn the idle speed screw (LA)counterclockwise until cutting toolstops rotating and then turn itabout another one full turn in thesame direction.

H L

LA

250R

A220

1 2

3

VA

250R

A221

1H L

LD

VA

8.2.4 Adjusting(three screws)

42 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Turn the idle speed screw (LD)counterclockwise until cutting toolstops rotating and then turn itabout another one full turn in thesame direction.

Note:If the engine does not reach6,000 rpm in starting throttleposition, readjust the throttlecable, see 7.5.

The carburetor has no adjustingscrews for maximum enginespeed (H screw) or idle mixture(L screw).The carburetor is tuned so that theengine receives an optimum fuel-air mixture in all operation condi-tions.

A slight correction of the idlespeed may be necessary. Use thefollowing procedure:

- Mount approved cutting tool.

- Check the air filter, replace ifnecessary.

- Check spark arresting screen,clean or replace as necessary.

- Start the engine and allow it towarm up.

Adjust idle speed correctly with theidle speed screw (LD): the cuttingtool must not rotate.

Adjusting idle speed

Engine stops while idling:

Turn the idle speed adjustingscrew (LD) clockwise until engineruns smoothly cutting tool mustnot rotate.

Cutting tool rotates whileengine is idling:

Turn the idle speed screw (LD)counterclockwise until cutting toolstops rotating and then turnscrew about another one full in thesame direction.

Note:If the engine does not reach6,000 rpm in starting throttleposition, readjust the throttlecable, see 7.5.

8.2.5 Adjusting(one screw)

250R

A222

1

LD+

-

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 43

Correct operation of the carburetoris only possible if atmosphericpressure and internal fuel tankpressure are equal at all times.This is ensured by the tank vent.

Important: If problems occur onthe carburetor or the fuel supplysystem, always check and cleanthe tank vent.

Check function by performingpressure and vacuum tests onthe tank via the fuel hose.

Equalization of pressure from theoutside inwards takes place viathe hole in the fuel filler cap, thesintered filter, the valve and holesin the cap.

Equalization of pressure from theinside outwards takes place viathe holes in the cap, the holes inthe valve body, the sintered filterand the hole in the fuel filler cap.

Cleaning

- Unscrew the fuel filler cap.

Ease the cap (1) off the valvebody (2).

Take sintered filter (3) out of cap. Pry valve body out of fuel filler

cap (4). Pry sintered filter (5) out of fuel

filler cap.

- Wash valve body in cleangasoline.

If diaphragm in the valve (6) isdamaged, pull it out of valvebody and fit new one.

Push new sintered filter (5) intofiller cap.

Fit sealing ring (7) over valvebody.

- Fit valve body in filler cap andpress it home until it snaps intoposition.

- Fit new sintered filter in the cap.

- Fit cap on valve body and pressit down until it snaps into position.

- Refit the fuel filler cap.

The diaphragm pump draws fuelout of the tank and into thecarburetor via the fuel hose. Anyimpurities mixed with the fuel areretained by the pickup body (filter).The fine pores of the filter even-tually become clogged with minuteparticles of dirt. This restricts thepassage of fuel and results in fuelstarvation.

Important: In the event of troublewith the fuel supply system,always check the fuel tank andthe pickup body first. Clean thefuel tank if necessary.

Cleaning the fuel tank

- Unscrew the filler cap and drainthe tank.

- Pour a small amount of cleangasoline into the tank.

- Close the tank and shake theunit vigorously.

- Open the tank again and drain it.

Note: Dispose of fuel properly.

Pickup body

- Unscrew the filler cap and re-move it together with the retainer.

8.3 Tank Vent 8.4 Pickup Body

250R

A225

1

73

2

5

6

4

VA

250R

A223

VA25

0RA2

24VA

44 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Use hook (1) 5910 893 8800 topull the pickup body out of thefuel tank.

Note: Do not stretch the fuel hose.

Pull the pickup body off the fuelhose.

- Fit new pickup body.

Install in the reversesequence.

All models- Drain the fuel tank.


- Remove the fan housing - see6.2.1.

FS 120...350, FR 350- On FR 350, remove powerhead

from support frame - see 9.3.

- Remove the filter housing - see8.2.1.

Pull fuel hose off carburetorelbow connector.


- Remove the fuel tank.

- Replace sleeves and grommetsif necessary.

- Remove fuel hoses if necessary.



FS 400/450, FR 450- On FR 450, remove powerhead

from support frame - see 9.3.

- Remove the carburetor - see8.2.2.

Disconnect fuel hose from lowerconnector on manual fuel pumpand pull it out of the guide.

FS 400/450 only Take out the screws.

- Remove the guard plate.

8.5 Fuel Tank/Hoses

250R

A176

VA25

0RA1

77VA

250R

A178

VA

250R

A174

1

VA25

0RA1

75VA

250R

A179

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 45


- Remove the fuel tank.

Take sleeves (1) out ofgrommets.

Ease grommets (2) out of fueltank.

- Remove fuel hoses if necessary.



Fuel hoses

- Unscrew filler cap and removetogether with retainer.

Use hook (1) 5910 893 8800 topull pickup body out of tank.

Pull pickup body off the fuel hose.

Pull out the fuel hose (1). Pull out the return hose (2)

together with grommet (3).

Install in the reverse sequence.

On FS 400/450, FR 450, fit fuelhose (1) next to filler neck (2).

Length "A" of return hose mustbe 190 mm (7.5") on FS120...350 and 200 mm (7.9") onFS 400/450.

250R

A183

1

3

2

VA25

0RA1

81

1

VA

250R

A184

12

VA

250R

A182

VA

250R

A180

VA25

0RA2

26

1

2

VA

250R

A185

A

VA

46 FS 120, 200, 300, 350, 400, 450, FR 350, 450


- On FS 120...350, FR 350,remove the air filter - see 8.1.

Disconnect hoses fromconnectors.

Carefully push back the retainingtabs.

Pull fuel pump out of its seat inthe filter/ carburetor housing.

Install in the reversesequence.

The anti-vibration (AV) connectionbetween the engine and drive tubeconsists of a rubber elementinstalled in the clutch housing.

- Remove the drive tube - see10.6.


- Remove the clutch housing andclutch shroud.

Take the clutch shroud off theclutch housing.

Lever the retaining ring out of theclutch housing.

- Remove retaining ring overthe AV sleeve.

Push installing tool (1)4126 893 4900 into AV sleeveas far as stop.

Tighten down clamp screw (2). Tighten fixing screw (3) modera-

tely if necessary.

- Apply a little lubricant (e.g. was-hing-up liquid) between theclutch housing and rubber ele-ment.

8.6 Manual Fuel Pump 9. AV SYSTEM9.1 Repair (FS 120/200)

250R

A189

VA25

0RA1

86VA

250R

A187

VA

250R

A190

VA25

0RA1

91VA

250R

A192

VA25

0RA1

93

23

1

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 47

- Clamp installing tool in vice.

Pull clutch housing offthe rubber element.

Release clamp screw (1) andfixing screw (2) if necessary.

Pull the AV sleeve (3) off theinstalling tool.

Pull the rubber element off theAV sleeve.

Push the rubber element,tapered end (1) first, onto the AVsleeve until the flange (2) isbehind the rubber element.

- Coat rubber element with a lubri-cant (e.g. washing-up liquid).

Push the rubber element intoclutch housing as far as stop sothat slot (1) is opposite the lug(2).

Assemble all parts in the reversesequence.

- Retaining ring must locateproperly in the groove in theclutch housing.

- Tighten down clutch housingmounting screws to 6.0 Nm(4.4 lbf.ft).

The anti-vibration (AV) connectionbetween the engine and drive tubeconsists of four rubber buffers inthe AV housing.

- Remove the control handle - see10.1.

Rubber buffers

Press snap hook (1) down andremove the cover (2).

Carefully ease the cableretainers out of the AV housing.

9.2 Repair(FS 300...450)

250R

A194

VA39

2RA1

34

2

1

3

VA39

2RA1

35VA

392R

A136

2

1

VA25

0RA1

95

1

2

VA

250R

A196

2 1

VA25

0RA1

97VA

48 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Release clamp screw on support.

Push the support forwards andpull off the rubber buffers.

- Push the AV housing forwards.

Pull the rubber buffers off theclutch housing.

- Slip the rubber buffers over thepegs on the clutch housing andsupport.

- Coat rubber buffers with a littlelubricant (e.g. washing-up liquid).

- Push AV housing onto the rub-ber buffers.

- Push support onto AV housingand engage the rubber buffersas the same time.

To set the gap (7 mm/0.27")between the clutch housing andAV housing, fit steel bar (e.g.120x30x7 mm) at both sides(see ill.).

Fit a steel bar (e.g. 90x30x7 mm)at both sides between the AVhousing and support.

Push support in direction of AVhousing until the four steel barsare tight.

- Tighten down screw to 6.0 Nm(4.4 lbf.ft).

- Take out the steel bars.

Assemble all parts in thereverse sequence.

- Place cover in the lower slot andpush it home until it snaps intoposition.

AV housing

- Remove bike handle -see 10.2.

- Remove the gearhead - see 11.1.

- Remove throttle cable from AVhousing.

- Release clamp screw on support.

Pull the support (1) and AVhousing (2) off the drive tube.

250R

A198

VA25

0RA1

99VA

250R

A200

VA

250R

A201

VA25

0RA2

02VA

250R

A203

2 1

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 49

- Inspect rubber buffers, replace ifnecessary.

- Adjust gap after fitting the AVhousing and support.

Assemble all parts in thereverse sequence.

The anti-vibration connectionbetween the engine and supportframe consists of three springs.

- Remove flexible shaft fromclutch housing - see 10.5.

Take spline screws (1) and hex.head screw (2) out of clutch hou-sing.

- Take powerhead off the supportplate.

Hold screws steady and unscrewthe nuts (1).

Remove the springs (2) from thesupport plate.


- Use new locknuts and tightenthem down to 10 Nm (7.5 lbf.ft).

- Tighten down spline screws andhexagon head screw to 10 Nm(7.5 lbf.ft).

9.3 Repair(FR 350/450)

250R

A162

1

1

2

VA

250R

A242

2 1 1

2

1

2

VA

50 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Take out the screw.

- Pull off the control handle.

Unscrew the nuts (1). Remove lower clamp (2),

support block (3), bike handle (4)and upper clamp (5) with screws(6).

Use jaws (1) 5910 893 2700 toclamp bike handle tube in vice.

- To replace left grip, carefully cutit open and pull it off.

- Coat inside of new grip with alittle lubricant (e.g. washing-upliquid).

Note: If too much lubricant isused, the grip will twist on thetube. Always leave it to dry for awhile after fitting.

Push the grip into position sothat the longer ends (see arrows)point toward the gearhead at anangle of 7 - 15 degrees to theshaft.

Assemble all parts in the reversesequence.

- Remove the control handle - see10.1.

Take out the clamp screw (1). Swing open the upper clamp (2)

and lift it away.

Remove bike handle (3) andlower clamp (4).

If necessary, take springs (5) ofout lower clamp.

- Replace left grip if necessary -see 10.1.


- Lubricate thread of clamp screwwith STIHL multipurpose grease -see 13.2

10. SHAFT 10.2 Bike Handle10.1 Bike Handle (FS 120/200) (FS 300...450)

250R

A205

4

1

2

5

3

5

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 51

Loop handle without barrier bar

Unscrew the nuts (1). Remove lower clamp (2).

Remove screws (1). Remove the loop handle (2) and

upper clamp (3).Reassemble in the reversesequence.

Align the loop handle atdistance "A" = 20 cm (8") fromthe control handle and tightendown firmly.

Loop handle with barrier bar

Take out screws (1). Remove lower clamp (2).

Remove the barrier bar (1), loophandle (2) and upper clamp (3).

Take the square nuts (4) out ofthe barrier bar.


Align the loop handle atdistance "A" = 20 cm (8") fromthe control handle and tightendown firmly.

The drive shaft is supported in aflexible liner inside the drive tube.The ends of the drive tube aresealed with plugs.

- Remove the gearhead - see 11.1.

Drive shaft

Pull the drive shaft out of thedrive tube.

Note: If the shaft has turned blue,fit a new one.

- Coat the drive shaft with STIHLgear lubricant 0781 120 1109,see 13.2, before installation.

Important: Apply the greaseuniformly and thinly to the wholedrive shaft. Do not pump greasedirectly into the drive tube.

- Push the drive shaft into thedrive tube.

10.3 Loop Handle 10.4 Drive Shaft/Flexible Liner

52 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Push the drive shaft into thedrive tube until dimension "A" is20 mm/0.8" (FS 120/200) or 30mm/1.2" (FS 300...450).If necessary, apply slight pres-sure to the shaft and rotate itslowly until it can be pushed in tothe specified dimension.

- Fit the gearhead - see 11.1.

Flexible liner

- Remove the drive tube - see10.6.

Pry the plug out of the drive tube.

Pull out the flexible liner.

On FS 120/200, the hole (1)must be between the spokes (2).

- Insert plug, install the drive tube -see 10.6.

Take throttle cable out of the tworetainers.

Press down lever on clutchhousing.

- Pull out the shaft.

Press down lever on housing.

- Pull out the shaft.

10.5 Flexible Shaft(FR 350/450)

362R

A177

A

VA

250R

A241

VA25

0RA2

40VA

250R

A243

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 53

Pull flexible shaft out of thedrive tube.

Note: If flexible shaft has turnedblue, fit a new one.

- Coat the flexible shaft withSTIHL gear lubricant 0781 1201109, see 13.2, before installa-tion.

Important: Apply the greaseuniformly and thinly to the wholeshaft. Do not pump grease directlyinto the drive tube.

Inspect the 0-ring and fit a newone if necessary.

- Install flexible shaft and fitthrottle cable in the retainers.

FS 120/200- Remove the drive shaft - see

10.4.

- Remove the bike or loop handle -see 10.1 and 10.3.

On machines with bike handle,take throttle cable out ofretainers.

On machines with loop handle,release screws on control handleclamps.

Take the fixing screw (1) out ofthe AV sleeve.

Release the clamp screw (2).

- Pull out the drive tube.

On machines with loop handle,pull the drive tube (1) out of thecontrol handle (2) at the sametime.

Slip the throttle cable retainer, iffitted, off the drive tube.

392R

A129

VA

2

1

392R

A156

2 1

VA

10.6 Drive Tube

250R

A206

VA

362R

A174

362R

A174

VA36

2RA1

7536

2RA1

75VA

54 FS 120, 200, 300, 350, 400, 450, FR 350, 450

Remove screw from hose clampfor harness.

Pull the hose clamp apart andtake it off the drive tube.

Pull off the sleeve, if fitted.


Degrease the clamp mountingarea and push the drive tubehome so that the holes line up.

- Tighten down fixing screw to2.5 Nm (1.8 lbf.ft) and clampscrew to 5.5 Nm (4.0 lbf.ft).

FS 300...450- Remove the AV housing - see

9.2.

- Remove the drive shaft - see10.4.

Release the clamp screw.

- Pull the drive tube out of theclutch housing.


- Degrease the clamp mountingarea and push the drive tubehome into clutch housing as faras stop.

- Tighten down clamp screw to8.5 Nm (6.3 lbf.ft) (FS 300/350)or 12 Nm (8.8 lbf.ft) (FS 400/450).

FR 350/450- Remove the drive shaft - see

10.4.

- Remove the housing - see 10.7.

Release screws (1) on clamps ofcontrol handle (2).

Pull off the control handle.

Pull off the sleeve (3).Reassemble in the reversesequence.

- Line up control handle relative tohousing - see 7.4.

- Tighten screws on clamps to2.0 Nm (1.5 lbf.ft).

250R

A207

VA

392R

A139

VA25

0RA2

08VA

250R

A249

1 2 1 3

VA

FS 120, 200, 300, 350, 400, 450, FR 350, 450 55

Press down the lever.

Pull out the flexible shaft.

Release the clamp screw (1). Pull off the housing (2).- Service the housing - see

"Standard Repairs, Trouble-shooting" handbook.


- Degrease clamp mounting area.

- Tighten down clamp screw to4.5 Nm (3.3 lbf.ft).

Illustration shows FS 120/200gearhead.

- Remov

Documents

STIHL FS 350 Service manual.pdf