Yamaha YZ250F X 2008 Owner'S Service Manual Download Page 178

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6-5

THROTTLE POSITION SENSOR SYSTEM

INSPECTION STEPS
If the throttle position sensor will not operate, use the following inspection steps.

*marked: Refer to "IGNITION SYSTEM" section.

Use the following special tools in this inspection.

Check entire ignition system for connection.

No good

→

Repair or replace.

↓

Check throttle position sensor. (Throttle position
sensor coil)

No good

→

Replace.

↓

*Check CDI magneto. (Charging coil)

No good

→

Replace.

↓

Check CDI unit. (Throttle position sensor input
voltage)

No good

→

Replace.

Pocket tester:

YU-3112-C/90890-03112

Summary of Contents for YZ250F X 2008

Page 1: ...UAL MANUEL D ATELIER DU PROPRIETAIRE FAHRER UND WARTUNGSHANDBUCH MANUALE DI SERVIZIO DEL PROPRIETARIO PRINTED IN JAPAN 2007 05 3 1 1 CR E F G H YZ250F X PRINTED ON RECYCLED PAPER YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN 2008 2008 ...

Page 2: ......

Page 3: ...YZ250F X 5XC 28199 34 E0 2008 OWNER S SERVICE MANUAL ...

Page 4: ......

Page 5: ...S SERVICE MANUAL 2007 by Yamaha Motor Co Ltd 1st Edition April 2007 All rights reserved Any reprinting or unauthorized use without the written permission of Yamaha Motor Co Ltd is expressly prohibited Printed in Japan ...

Page 6: ...Please check local regulations before riding 1 THIS MACHINE IS TO BE OP ERATED BY AN EXPERI ENCED RIDER ONLY Do not attempt to operate this machine at maximum power until you are totally familiar with its characteristics 2 THIS MACHINE IS DESIGNED TO BE RIDDEN BY THE OP ERATOR ONLY Do not carry passengers on this machine 3 ALWAYS WEAR PROTEC TIVE APPAREL When operating this ma chine always wear an...

Page 7: ... TO USE THIS MANUAL FINDING THE REQUIRED PAGE 1 This manual consists of seven chapters General Information Specifications Regular inspec tion and adjustments Engine Chassis Electrical and Tun ing 2 The table of contents is at the be ginning of the manual Look over the general layout of the book be fore finding then required chapter and item Bend the book at its edge as shown to find the required f...

Page 8: ... more informa tion the step by step format sup plements 5 are given in addition to the exploded diagram and job instruction chart ILLUSTRATED SYMBOLS Refer to the illustration Illustrated symbols 1 to 7 are used to identify the specifications appear ing in the text 1 With engine mounted 2 Filling fluid 3 Lubricant 4 Special tool 5 Tightening 6 Specified value Service limit 7 Resistance Ω Voltage V...

Page 9: ...TABLE OF CONTENTS GENERAL INFORMATION 1 SPECIFICATIONS 2 REGULAR INSPECTION AND ADJUSTMENTS 3 ENGINE 4 CHASSIS 5 ELECTRICAL 6 TUNING 7 ...

Page 10: ...S 3 14 ELECTRICAL 3 23 CHAPTER 4 ENGINE SEAT FUEL TANK AND SIDE COVERS 4 1 EXHAUST PIPE AND SILENCER 4 3 RADIATOR 4 5 CARBURETOR 4 7 CAMSHAFTS 4 14 CYLINDER HEAD 4 19 VALVES AND VALVE SPRINGS 4 21 CYLINDER AND PISTON 4 25 CLUTCH 4 29 OIL FILTER ELEMENT AND WATER PUMP 4 34 BALANCER 4 38 OIL PUMP 4 40 KICK SHAFT AND SHIFT SHAFT 4 44 CDI MAGNETO 4 49 ENGINE REMOVAL 4 51 CRANKCASE AND CRANKSHAFT 4 55 ...

Page 11: ...ct to change without notice 1 Clutch lever 2 Hot starter lever 3 Front brake lever 4 Throttle grip 5 Radiator cap 6 Fuel tank cap 7 Engine stop switch 8 Kickstarter crank 9 Fuel tank 10 Radiator 11 Coolant drain bolt 12 Rear brake pedal 13 Valve joint 14 Fuel cock 15 Cold starter knob 16 Drive chain 17 Air filter 18 Oil level check window 19 Shift pedal 20 Front fork 1 ...

Page 12: ...d before starting out VALVE JOINT This valve joint 1 prevents fuel from flowing out and is installed to the fuel tank breather hose In this installation make sure the arrow faces the fuel tank and also downward SPARK PLUG WRENCH This spark plug wrench 1 is used to remove and install the spark plug NIPPLE WRENCH This nipple wrench 1 is used to tighten the spoke JET NEEDLE PULL UP TOOL The jet needl...

Page 13: ...amped letters must be on the side exposed to view When in stalling oil seal s apply a light coating of lightweight lithium base grease to the seal lip s Oil the bearings liberally when installing Do not use compressed air to spin the bearings dry This causes dam age to the bearing surfaces CIRCLIPS 1 All circlips should be inspected carefully before reassembly Al ways replace piston pin clips afte...

Page 14: ...ase separating tool YU 1135 A 90890 01135 These tool is used to remove the crankshaft from either case Flywheel puller YM 1189 90890 01189 This tool is used to remove the fly wheel magneto Rotor holding tool YU 1235 90890 01235 This tool is used when loosening or tightening the flywheel magneto se curing nut Dial gauge and stand YU 3097 90890 01252 Stand YU 1256 These tools are used to check each ...

Page 15: ...nut to specification Cap bolt wrench YM 01500 90890 01500 This tool is used to loosen or tighten the base valve Cap bolt ring wrench YM 01501 90890 01501 This tool is used to loosen or tighten the damper assembly Fork seal driver YM A0948 90890 01502 This tool is used when install the fork oil seal Pocket tester YU 3112 C 90890 03112 Use this tool to inspect the coil resis tance output voltage and...

Page 16: ...oss securing nut Valve guide remover Intake 4 0 mm 0 16 in Exhaust 4 5 mm 0 18 in YM 4111 90890 04111 YM 4116 90890 04116 This tool is needed to remove and install the valve guide Valve guide installer Intake 4 0 mm 0 16 in Exhaust 4 5 mm 0 18 in YM 4112 90890 04112 YM 4117 90890 04117 This tool is needed to install the valve guide Valve guide reamer Intake 4 0 mm 0 16 in Exhaust 4 5 mm 0 18 in YM...

Page 17: ...tion checker 90890 06754 This instrument is necessary for checking the ignition system compo nents YAMAHA Bond No 1215 ThreeB ond No 1215 90890 85505 This sealant Bond is used for crankcase mating surface etc Tool name Part number How to use Illustration ...

Page 18: ...EAR BRAKE PEDAL The rear brake pedal 1 is located on the right side of the machine Press down on the brake pedal to activate the rear brake FUEL COCK The fuel cock supplies fuel from the tank to carburetor and also filters the fuel The fuel cock has the two posi tions OFF With the lever in this position fuel will not flow Always return the lever to this position when the engine is not running ON W...

Page 19: ...e this model is equipped with an accelerator pump if the engine is raced the throttle opened and closed the air fuel mixture will be too rich and the engine may stall Also unlike a two stroke engine this model can idle Do not warm up the engine for ex tended periods of time STARTING A WARM ENGINE Do not operate the cold starter knob and throttle Pull the hot starter lever 1 and start the engine by...

Page 20: ... 2 open low to me dium speed for about one hour 6 Restart the engine and check the operation of the machine through out its entire operating range Re start the machine and operate it for about 10 to 15 more minutes The machine will now be ready to race After the break in or before each race you must check the entire machine for loose fittings and fasteners as per TORQUE CHECK POINTS Tighten all su...

Page 21: ...ink type Assembly of links Link to frame Link to rear shock absorber Link to swingarm Installation of rear shock absorber Rear shock absorber to frame Installation of swingarm Tightening of pivot shaft Wheel Installation of wheel Front Tightening of wheel axle Tightening of axle holder Rear Tightening of wheel axle Wheel to rear wheel sprocket Brake Front Brake caliper to front fork Brake disc to ...

Page 22: ...ain with a paper towel and lubri cate the chain to prevent rust 7 Clean the seat with a vinyl uphol stery cleaner to keep the cover pliable and glossy 8 Automotive wax may be applied to all painted or chromed surfac es Avoid combination cleaner waxes as they may contain abra sives 9 After completing the above start the engine and allow it to idle for several minutes STORAGE If your machine is to b...

Page 23: ...linder arrangement Single cylinder forward inclined Displacement 249 cm3 8 76 Imp oz 8 42 US oz Bore stroke 77 0 53 6 mm 3 03 2 11 in Compression ratio 13 5 1 Starting system Kickstarter Lubrication system Dry sump Oil type or grade Engine oil For USA and CDN Yamalube 4 SAE10W30 or SAE20W40 Yamalube 4 R SAE10W50 API service SG type or higher JASO standard MA Except for USA and CDN SAE10W30 SAE10W4...

Page 24: ...ration Gear ratio 1st 30 14 2 143 2nd 28 16 1 750 3rd 29 20 1 450 4th 27 22 1 227 5th 25 24 1 042 Chassis USA CDN AUS NZ ZA EUROPE Frame type Semi double cradle Caster angle 27 1 26 9 Trail 116 9 mm 4 60 in 115 1 mm 4 53 in Tire Type With tube Size front 80 100 21 51M Size rear 100 90 19 57M Tire pressure front and rear 100 kPa 1 0 kgf cm2 15 psi Brake Front brake type Single disc brake Operation ...

Page 25: ...22 021 mm 0 8661 0 8670 in Camshaft outside diameter 21 959 21 972 mm 0 8645 0 8650 in Shaft to cap clearance 0 028 0 062 mm 0 0011 0 0024 in 0 08 mm 0 003 in Cam dimensions Intake A 30 246 30 346 mm 1 1908 1 1947 in 30 146 mm 1 1869 in Intake B 22 45 22 55 mm 0 8839 0 8878 in 22 35 mm 0 8799 in Exhaust A 30 399 30 499 mm 1 1968 1 2007 in 30 299 mm 1 1929 in Exhaust B 22 45 22 55 mm 0 8839 0 8878 ...

Page 26: ... EX 0 9 1 1 mm 0 0354 0 0433 in 1 6 mm 0 0630 in D margin thickness IN 0 8 mm 0 0315 in D margin thickness EX 0 7 mm 0 0276 in Stem outside diameter IN 3 975 3 990 mm 0 1565 0 1571 in 3 945 mm 0 1553 in Stem outside diameter EX 4 460 4 475 mm 0 1756 0 1762 in 4 430 mm 0 1744 in Guide inside diameter IN 4 000 4 012 mm 0 1575 0 1580 in 4 050 mm 0 1594 in Guide inside diameter EX 4 500 4 512 mm 0 177...

Page 27: ...at 29 13 mm 9 9 11 4 kg at 29 13 mm 22 27 25 57 lb at 1 15 in Compressed force installed EX 126 144 N at 29 30 mm 12 6 14 4 kg at 29 30 mm 28 44 32 41 lb at 1 15 in Tilt limit IN 2 5 1 7 mm 2 5 0 067 in Tilt limit EX 2 5 1 6 mm 2 5 0 063 in Direction of winding top view IN Clockwise Direction of winding top view EX Clockwise Piston Piston to cylinder clearance 0 030 0 055 mm 0 0012 0 0022 in 0 1 m...

Page 28: ...lled 0 30 0 45 mm 0 012 0 018 in 0 80 mm 0 031 in Side clearance 0 020 0 055 mm 0 0008 0 0022 in 0 12 mm 0 005 in Oil ring Dimensions B T 1 50 2 25 mm 0 06 0 09 in End gap installed 0 10 0 40 mm 0 004 0 016 in Crankshaft Crank width A 55 95 56 00 mm 2 203 2 205 in Runout limit C 0 03 mm 0 0012 in 0 05 mm 0 002 in Big end side clearance D 0 15 0 45 mm 0 0059 0 0177 in 0 50 mm 0 02 in Small end free...

Page 29: ...t needle clip position J N NFPR 5 Cutaway C A 1 5 Pilot jet P J 42 Pilot air jet P A J 105 Pilot outlet P O ø0 9 Pilot screw example P S 2 3 8 Bypass B P ø1 0 Valve seat size V S ø3 8 Starter jet G S 72 Leak jet Acc P 70 Float height F H 8 mm 0 31 in Engine idle speed 1 900 2 100 r min Intake vacuum 29 3 34 7 kPa 220 260 mmHg 8 66 9 45 inHg Hot starter lever free play 3 6 mm 0 12 0 24 in Lubricati...

Page 30: ...mp oz 17 6 US oz Oil grade Suspension oil S1 Inner tube outer diameter 48 mm 1 89 in Front fork top end 5 mm 0 20 in Rear suspension USA CDN AUS NZ ZA EUROPE Shock absorber travel 131 5 mm 5 18 in Spring free length Approx 275 mm 10 83 in Fitting length One I D mark 268 mm 10 55 in 262 mm 10 31 in Two I D marks 274 mm 10 79 in 268 mm 10 55 in Three I D marks 265 5 mm 10 45 in 259 5 mm 10 22 in Min...

Page 31: ...ake fluid type DOT 4 Rear disc brake Disc outside dia Thickness 245 4 0 mm 9 65 0 16 in 245 3 5 mm 9 65 0 14 in Deflection limit 0 15 mm 0 006 in Pad thickness 6 4 mm 0 25 in 1 0 mm 0 04 in Master cylinder inside dia 11 0 mm 0 433 in Caliper cylinder inside dia 25 4 mm 1 000 in 1 Brake fluid type DOT 4 Brake lever and brake pedal Brake lever position 95 mm 3 74 in Brake pedal height vertical heigh...

Page 32: ...Cylinder head bolt M9 1 25 4 38 3 8 27 Cylinder head nut M6 1 0 2 10 1 0 7 2 Cylinder head cover M6 1 0 2 10 1 0 7 2 Cylinder M6 1 0 1 10 1 0 7 2 Balancer weight M6 1 0 2 10 1 0 7 2 Balancer shaft driven gear M14 1 0 1 50 5 0 36 Timing chain guide intake side M6 1 0 2 10 1 0 7 2 Timing chain tensioner M6 1 0 2 10 1 0 7 2 Timing chain tensioner cap bolt M6 1 0 1 7 0 7 5 1 Impeller M8 1 25 1 14 1 4 ...

Page 33: ...pper M6 1 0 11 10 1 0 7 2 Crankcase bearing stopper crankshaft M6 1 0 4 14 1 4 10 Oil level check window holder M6 1 0 1 10 1 0 7 2 Left crankcase cover M6 1 0 8 10 1 0 7 2 Right crankcase cover M6 1 0 8 10 1 0 7 2 Clutch cover M6 1 0 7 10 1 0 7 2 Crankcase oil drain bolt M10 1 25 1 20 2 0 14 Crankshaft end accessing screw M32 1 5 1 Timing mark accessing screw M14 1 5 1 Drive chain sprocket cover ...

Page 34: ...ip cap M5 0 8 2 4 0 4 2 9 Front brake master cylinder M6 1 0 2 9 0 9 6 5 Brake lever mounting bolt M6 1 0 1 6 0 6 4 3 Brake lever mounting nut M6 1 0 1 6 0 6 4 3 Brake lever position locknut M6 1 0 1 5 0 5 3 6 Clutch lever holder M5 0 8 2 4 0 4 2 9 Clutch lever mounting nut M6 1 0 1 4 0 4 2 9 Hot starter lever holder M5 0 8 2 4 0 4 2 9 Front brake master cylinder cap M4 0 7 2 2 0 2 1 4 Front brake...

Page 35: ... 0 58 Rear shock absorber and frame M10 1 25 1 56 5 6 40 Rear shock absorber and relay arm M10 1 25 1 53 5 3 38 Rear frame upper M8 1 25 1 38 3 8 27 Rear frame lower M8 1 25 2 32 3 2 23 Swingarm and brake hose holder M5 0 8 4 2 0 2 1 4 Swingarm and patch M4 0 7 4 2 0 2 1 4 Upper drive chain tensioner M8 1 25 1 16 1 6 11 Lower drive chain tensioner M8 1 25 1 16 1 6 11 Drive chain support M6 1 0 3 7...

Page 36: ...by using the steering nut wrench then loosen the steering ring nut one turn 2 Retighten the steering ring nut 7 Nm 0 7 m kg 5 1 ft lb ELECTRICAL Part to be tightened Thread size Q ty Tightening torque Nm m kg ft lb Stator M6 1 0 3 10 1 0 7 2 Rotor M12 1 25 1 56 5 6 40 Neutral switch M5 0 8 2 4 0 4 2 9 ...

Page 37: ...ts should be at room temperature A Distance between flats B Outside thread diameter DEFINITION OF UNITS A Nut B Bolt TORQUE SPECIFI CATION Nm m kg ft lb 10 mm 6 mm 6 0 6 4 3 12 mm 8 mm 15 1 5 11 14 mm 10 mm 30 3 0 22 17 mm 12 mm 55 5 5 40 19 mm 14 mm 85 8 5 61 22 mm 16 mm 130 13 94 Unit Read Definition Measure mm millimeter 10 3 meter Length cm centimeter 10 2 meter Length kg kilogram 103 gram Wei...

Page 38: ...2 16 LUBRICATION DIAGRAMS LUBRICATION DIAGRAMS 1 Oil filter element 2 Oil pump 3 Drive axle 4 Main axle 5 Intake camshaft 6 Exhaust camshaft 7 Oil tank 8 Oil delivery pipe A To oil tank ...

Page 39: ...2 17 LUBRICATION DIAGRAMS 1 Crankshaft 2 Oil filter element 3 Oil tank 4 Oil hose A From oil pump ...

Page 40: ...uel hose 12 Carburetor overflow hose A Insert the end of the fuel tank breather hose into the hole in the steering stem B Install the connector cover so that it does not come in between the radiator hose 1 and radiator C Aligh the paint mark on the cylin der head breather hose with the front end of the hose guide D Pass the cylinder head breather hose on the outside of the radia tor hose 1 and the...

Page 41: ...el hose between the hot starter cable and throttle po sition sensor lead H Pass the carburetor breater hos es so that they are not pinched between the upper engine bracket and carburetor I Pass the carburetor breather hoses and overflow hose so that all there hoses do not contact the rear shock absorber ...

Page 42: ...ch lead 14 Sub wire harness 15 CDI unit bracket 16 CDI unit 17 Throttle cable 18 Cylinder head breather hose A Fasten the hot starter cable throttle cables throttle position sensor lead and ignition coil lead B Fasten the throttle position sen sor lead behind the hump of the frame C Fasten the neutral switch lead on the oil hose D Pass the neutral switch lead on the inside of the oil hose E Fasten...

Page 43: ...ween the frame and radiator hose 4 H Fasten the sub wire harness and engine stop switch lead to the CDI unit bracket at the white taped portion of the subwire har ness and with the clamp ends facing downward I Locate the clamp ends in the ar rowed range J Fasten the neutral switch lead and CDI magneto lead over the hump of the frame K Fasten the hot starter cable and throttle cable onto the frame ...

Page 44: ... Cylinder head breather hose 6 Clamp 7 Rear arm bracket A Pass the throttle cables over the radiator hose 2 B Pass the cylinder head breather hose so that it does not contact the ignition coil C Fasten the throttle cables with the clamp so that the cables are not bent and pass them under the rear arm bracket ...

Page 45: ... directs as shown and lightly touches the projec tion on the brake caliper B Pass the brake hose into the brake hose holders C If the brake hose contacts the spring rear shock absorber correct its twist D Install the brake hose so that its pipe portion directs as shown and lightly touches the projec tion on the brake master cylin der ...

Page 46: ...e hose 8 Hose guide A Fasten the engine stop switch lead to the handlebar B Pass the clutch cable and hot starter cable through the cable guide C Pass the brake hose in front of the number plate D Pass the throttle cables through the cable guide E Pass the clutch cable and hot starter cable through the cable guide on the number plate ...

Page 47: ...ENGINE OIL Replace Inspect OIL FILTER ELEMENT OIL STRAINER Clean VALVES Check the valve clearances The engine must be cold Inspect Check the valve seats and valve stems for wear Replace VALVE SPRINGS Inspect Check the free length and the tilt Replace VALVE LIFTERS Inspect Check for scratches and wear Replace CAMSHAFTS Inspect the camshaft surface Inspect Inspect the decompression system Replace TI...

Page 48: ...nspect and clean CARBURETOR Inspect adjust and clean SPARK PLUG Inspect and clean Replace DRIVE CHAIN Use chain lube Lubricate slack alignment Chain slack 48 58 mm 1 9 2 3 in Replace COOLING SYSTEM Check coolant level and leakage Check radiator cap operation Replace coolant Every two years Inspect hoses OUTSIDE NUTS AND BOLTS Retighten Refer to STARTING AND BREAK IN section in the CHAPTER 1 AIR FI...

Page 49: ...place oil seal FRONT FORK OIL SEAL AND DUST SEAL Clean and lube Lithium base grease PROTECTOR GUIDE Replace REAR SHOCK ABSORBER Inspect and adjust Lube After rain ride Molybdenum disulfide grease Replace spring seat Every one year Retighten DRIVE CHAIN GUIDE AND ROLLERS Inspect SWINGARM Inspect lube and retighten Molybdenum disulfide grease RELAY ARM CONNECTING ROD Inspect lube and retighten Molyb...

Page 50: ...ate Lithium base grease THROTTLE CONTROL CABLE Check routing and connection Lubricate Yamaha cable lube or SAE 10W 30 motor oil Inspect and clean throttle ca ble Inspect dirt and wear on the throttle cable on the carburetor side HOT STARTER CLUTCH LEVER Inspect free play Item After break in Every race Every third or 500 km Every fifth or 1 000 km As re quired Remarks ...

Page 51: ...in slack and alignment Check that the drive chain is lubricated properly P 3 17 Wheels Check for excessive wear and tire pressure Check for loose spokes and have no excessive play P 3 20 Steering Check that the handlebar can be turned smoothly and have no ex cessive play P 3 20 21 Front forks and rear shock absorber Check that they operate smoothly and there is no oil leakage P 3 18 20 Cables wire...

Page 52: ...tap water 5 Install Copper washer Coolant drain bolt 6 Fill Radiator Engine To specified level Do not mix more than one type of ethylene glycol antifreeze con taining corrosion inhibitors for aluminum engine Do not use water containing im purities or oil Handling notes of coolant The coolant is harmful so it should be handled with special care When coolant splashes to your eye Thoroughly wash your...

Page 53: ...g the adjuster 5 After adjustment check proper op eration of clutch lever 3 Install Cap 1 Boot 2 Place the tip a of the cap in the boot ADJUSTING THE THROTTLE CABLE FREE PLAY 1 Check Throttle grip free play a Out of specification Adjust 2 Adjust Throttle grip free play Throttle grip free play adjustment steps a Slide the adjuster cover b Loosen the locknut 1 c Turn the adjuster 2 until the specifi...

Page 54: ...ueezing the element Do not twist the element when squeezing the element Leaving too much of solvent in the element may result in poor starting 3 Inspect Air filter element Damage Replace 4 Apply Foam air filter oil or equivalent oil to the element Squeeze out the excess oil Element should be wet but not dripping 5 Install Air filter guide 1 Align the projection a on filter guide with the hole b in...

Page 55: ...e suitable stand under the engine 3 Place a suitable container under the engine 4 Remove Lower engine guard 1 Bolt oil tank 2 Washer 3 Oil filler cap 4 Oil tank drain bolt 5 Crankcase oil drain bolt 6 Oil filter element drain bolt 7 Drain the crankcase and oil tank of its oil 5 Remove Oil hose clamp 1 Bolt oil hose Oil hose 2 Oil strainer 3 6 Inspect Oil strainer Clogged Blow 7 If the oil filter i...

Page 56: ...s out a Turn in the pilot screw until it is lightly seated b Turn out the pilot screw by the factory set number of turns ADJUSTING THE ENGINE IDLING SPEED 1 Start the engine and thoroughly warm it up 2 Adjust Engine idling speed Adjustment steps a Adjust the pilot screw Refer to ADJUSTING THE PI LOT SCREW section b Turn the throttle stop screw 1 until the specified engine idling speed Using a digi...

Page 57: ...d reading if the clearance is incorrect 5 Adjust Valve clearance Adjustment steps a Remove the camshaft intake and exhaust Refer to CAMSHAFTS section in the CHAPTER 4 b Remove the valve lifters 1 and the pads 2 Place a rag in the timing chain space to prevent pads from falling into the crankcase Identity each valve lifter and pad position very carefully so that they can be reinstalled in their ori...

Page 58: ...valve lifters 4 Apply the engine oil on the valve lift ers Apply the molybdenum disulfide oil on the valve stem ends Valve lifter must turn smoothly when rotated with a finger Be careful to reinstall valve lifters and pads in their original place g Install the camshafts exhaust and intake Refer to CAMSHAFTS section in the CHAPTER 4 ...

Page 59: ...3 13 ENGINE INTAKE EXHAUST ...

Page 60: ... bleeding procedure when the tiny bubbles in the system have disap peared j Add brake fluid to the level line on the reservoir Check the operation of the brake after bleeding the brake system 3 Install Protector rear brake Reservoir float front brake Diaphragm Brake master cylinder cap ADJUSTING THE FRONT BRAKE 1 Check Brake lever position a 2 Remove Brake lever cover 3 Adjust Brake lever position...

Page 61: ... the brake caliper re cesses b Temporarily tighten the pad pin at this point i Install the brake caliper 8 and tighten the pad pin 9 j Install the pad pin plug 10 3 Inspect Brake fluid level Refer to CHECKING THE BRAKE FLUID LEVEL section 4 Check Brake lever operation A softy or spongy feeling Bleed brake system Refer to BLEEDING THE HY DRAULIC BRAKE SYSTEM sec tion CHECKING AND REPLACING THE REAR...

Page 62: ... brake system Refer to BLEEDING THE HY DRAULIC BRAKE SYSTEM sec tion CHECKING THE REAR BRAKE PAD INSULATOR 1 Remove Brake pad Refer to CHECKING AND RE PLACING THE REAR BRAKE PADS section 2 Inspect Rear brake pad insulator 1 Damage Replace CHECKING THE BRAKE FLUID LEVEL 1 Place the brake master cylinder so that its top is in a horizontal po sition 2 Inspect Brake fluid level Fluid at lower level Fi...

Page 63: ...on Adjust Before checking and or adjusting ro tate the rear wheel through several revolutions and check the slack sev eral times to find the tightest point Check and or adjust the drive chain slack with the rear wheel in this tight chain position 3 Adjust Drive chain slack Drive chain slack adjustment steps a Loosen the axle nut 1 and lock nuts 2 b Adjust the drive chain slack by turning the adjus...

Page 64: ...k to the same setting Uneven adjust ment can cause poor handling and loss of stability ADJUSTING THE FRONT FORK COMPRESSION DAMPING FORCE 1 Adjust Compression damping force By turning the adjuster 1 STANDARD POSITION This is the position which is back by the specific number of clicks from the fully turned in position Do not force the adjuster past the minimum or maximum extent of adjustment The ad...

Page 65: ...nimum or maximum extent of adjustment The adjuster may be damaged ADJUSTING THE REAR SHOCK ABSORBER LOW COMPRESSION DAMPING FORCE 1 Adjust Low compression damping force By turning the adjuster 1 Stiffer Increase the spring pre load Turn the adjuster 2 in Softer Decrease the spring pre load Turn the adjuster 2 out Spring length installed a Standard length Extent of ad justment One I D mark 268 mm 1...

Page 66: ...alve stem indicates that the tire slips off its position on the rim If the tire valve stem is found tilted the tire is considered to be slipping off its position Correct the tire posi tion CHECKING AND TIGHTENING THE SPOKES 1 Inspect Spokes 1 Bend damage Replace Loose spoke Retighten 2 Tighten Spokes Be sure to retighten these spokes be fore and after break in After a prac tice or a race check spo...

Page 67: ... bearings h Install the washer 5 upper bracket 6 washer 7 steering stem nut 8 handlebar 9 han dlebar upper holder 10 and number plate 11 The handlebar upper holder should be installed with the punched mark a forward Install the handlebar so that the marks b are in place on both sides Install the handlebar so that the pro jection c of the handlebar upper holder is positioned at the mark on the hand...

Page 68: ...vot 5 Throttle to handlebar contact 6 Drive chain 7 Tube guide cable winding por tion 8 Throttle cable end 9 Clutch cable end 10 Hot starter cable end A Use Yamaha cable lube or equivalent on these areas B Use SAE 10W 30 motor oil or suitable chain lubricants C Lubricate the following areas with high quality lightweight lith ium soap base grease Wipe off any excess grease and avoid getting grease ...

Page 69: ...r if necessary 5 Tighten Spark plug Before installing a spark plug clean the gasket surface and plug sur face Finger tighten a the spark plug before torquing to specification b CHECKING THE IGNITION TIMING 1 Remove Timing mark accessing screw 1 2 Attach Timing light Inductive tachometer To the ignition coil lead orange lead 1 3 Adjust Engine idling speed Refer to ADJUSTING THE EN GINE IDLING SPEED...

Page 70: ...K AND SIDE COVERS Order Part name Q ty Remarks Turn the fuel cock to OFF Disconnect the fuel hose 1 Seat 1 2 Air scoop left and right 2 3 Bolt fuel tank 2 4 Fuel tank 1 5 Left side cover 1 Refer to removal section 6 Right side cover 1 Refer to removal section 7 Number plate 1 Refer to removal section ...

Page 71: ... a is inserted into the band of the number plate Pull the band off the projection before removal Remove the hot starter cable 2 and clutch cable 3 from the cable guide b on the number plate The projection c on the lower bracket is inserted into the number plate Remove the number plate by pulling it off the projection INSTALLING THE AIR SCOOP 1 Install Air scoop 1 Bolt air scoop Put the portion a o...

Page 72: ...AND SILENCER Order Part name Q ty Remarks Right side cover Refer to SEAT FUEL TANK AND SIDE COVERS section 1 Bolt silencer clamp 1 Only loosening 2 Bolt silencer front 1 3 Bolt silencer rear 1 4 Collar 1 5 Silencer 1 6 Silencer clamp 1 7 Nut exhaust pipe 2 8 Exhaust pipe 1 9 Gasket 2 ...

Page 73: ...ke care not to allow the fiber out of place when installing the inner pipe INSTALLING THE SILENCER AND EXHAUST PIPE 1 Install Gasket Exhaust pipe 1 Nut exhaust pipe 2 First temporarily install both nuts then tighten either of these nuts to 13 Nm 1 3 m kg 9 4 ft lb and the other to 20 Nm 2 0 m kg 14 ft lb and then come back to the first one and retighten it to 20 Nm 2 0 m kg 14 ft lb 2 Install Sile...

Page 74: ...ANT sec tion in the CHAPTER 3 Seat and fuel tank Refer to SEAT FUEL TANK AND SIDE COVERS section 1 Radiator guard 2 2 Radiator hose clamp 8 Only loosening 3 Radiator hose 1 1 4 Left radiator 1 5 Radiator hose 3 1 6 Right radiator 1 7 Radiator hose 2 1 8 Radiator hose 4 1 9 Radiator breather hose 1 10 Radiator pipe 1 1 ...

Page 75: ...in Repair replace INSTALLING THE RADIATOR 1 Install O ring 1 Radiator pipe 1 2 Bolt radiator pipe 3 Apply the lithium soap base grease on the O ring 2 Install Radiator breather hose 1 Radiator hose 2 2 Radiator hose 3 3 Radiator hose 4 4 To right radiator 5 3 Install Right radiator 1 Bolt right radiator 2 Radiator hose 3 3 Refer to CABLE ROUTING DIA GRAM section in the CHAPTER 2 4 Install Left rad...

Page 76: ...tle position sensor lead coupler 1 3 Throttle cable cover 1 4 Throttle cable 2 5 Clamp air filter joint 1 Loosen the screw air filter joint 6 Clamp carburetor joint 1 Loosen the screws carburetor joint 7 Hot starter plunger 1 8 Carburetor assembly 1 9 Carburetor joint 1 4 Nm 0 4 m kg 2 9 ft lb 4 Nm 0 4 m kg 2 9 ft lb 2 Nm 0 2 m kg 1 4 ft lb 3 Nm 0 3 m kg 2 2 ft lb 3 Nm 0 3 m kg 2 2 ft lb 11 Nm 1 1...

Page 77: ...ver housing cover 1 3 Screw throttle shaft 1 4 Throttle valve 1 5 Needle holder 1 6 Jet needle 1 7 Accelerator pump cover 1 8 Spring 1 9 Diaphragm accelerator pump 1 10 Float chamber 1 11 Leak jet 1 12 Pilot screw 1 Refer to removal section 13 Float pin 1 14 Float 1 15 Needle valve 1 16 Main jet 1 17 Needle jet 1 ...

Page 78: ...R 18 Spacer 1 19 Pilot jet 1 20 Starter jet 1 21 Push rod 1 Pull the push rod 22 Throttle shaft assembly 1 23 Push rod link lever assembly 1 24 Pilot air jet 1 25 Cold starter plunger 1 Order Part name Q ty Remarks ...

Page 79: ... b Clean Filter c Clogged Clean CHECKING THE THROTTLE VALVE 1 Check Free movement Stick Repair or replace Insert the throttle valve 1 into the carburetor body and check for free movement CHECKING THE JET NEEDLE 1 Inspect Jet needle 1 Bends wear Replace Clip groove Free play exists wear Replace Clip position MEASURING AND ADJUSTING THE FLOAT HEIGHT 1 Measure Float height a Out of specification Adju...

Page 80: ... fits on the stopper a of the lever 2 4 Install Spring 2 1 To lever 2 2 5 Install Push rod link lever assembly 1 Make sure the stopper a of the spring 2 fits into the recess b in the carburetor 6 Install Washer 1 Circlip 2 7 Install Spring 1 To throttle shaft 2 Install the bigger hook a of the spring fits on the stopper b of the throttle shaft pulley 8 Install Throttle shaft assembly 1 Washer meta...

Page 81: ...f turns recorded before removing 13 Install O ring Leak jet 1 Float chamber 2 Bolt float chamber 3 Cable holder throttle stop screw cable 4 Hose holder carburetor breather hose 5 14 Install Diaphragm accelerator pump 1 Spring 2 O ring 3 Accelerator pump cover 4 Hose holder drain hose 5 Screw accelerator pump cover 6 Install the diaphragm accelerator pump with its mark a facing the spring 15 Instal...

Page 82: ...joint 1 2 Install Carburetor 1 Install the projection a between the carburetor joint slots 3 Install Hot starter plunger 1 4 Tighten Bolt carburetor joint 1 Bolt air filter joint 2 5 Install Throttle cable pull 1 Throttle cable return 2 6 Adjust Throttle grip free play Refer to ADJUSTING THE THROTTLE CABLE FREE PLAY section in the CHAPTER 3 7 Install Throttle cable cover 1 Bolt throttle cable cove...

Page 83: ... Order Part name Q ty Remarks Seat and fuel tank Refer to SEAT FUEL TANK AND SIDE COVERS section 1 Spark plug 1 2 Cylinder head breather hose 1 3 Bolt cylinder head cover 2 4 Cylinder head cover 1 5 Cylinder head cover gasket 1 6 Timing chain guide top side 1 ...

Page 84: ...shaft end accessing screw 1 Refer to removal section 3 Timing chain tensioner cap bolt 1 Refer to removal section 4 Timing chain tensioner 1 Refer to removal section 5 Camshaft cap 2 Refer to removal section 6 Clip 2 Refer to removal section 7 Exhaust camshaft 1 Refer to removal section 8 Intake camshaft 1 Refer to removal section ...

Page 85: ...cap 2 Clip Remove the bolts camshaft cap in a crisscross pattern working from the outside in The bolts camshaft cap must be removed evenly to prevent dam age to the cylinder head cam shafts or camshaft caps 5 Remove Exhaust camshaft 1 Intake camshaft 2 Attach a wire 3 to the timing chain to prevent it from falling into the crank case CHECKING THE CAMSHAFT 1 Inspect Cam lobe Pitting scratches blue ...

Page 86: ...ion mechanism cam 1 moves smoothly b Check that the decompression mechanism cam lever pin 2 projects from the camshaft CHECKING THE TIMING CHAIN TENSIONER 1 Check While pressing the tensioner rod lightly with fingers use a thin screwdriver 1 and wind the ten sioner rod up fully clockwise When releasing the screwdriver by pressing lightly with fingers make sure that the tensioner rod will come out ...

Page 87: ...e pressing the tensioner rod lightly with fingers use a thin screwdriver and wind the tension er rod up fully clockwise b With the rod fully wound and the chain tensioner UP mark a fac ing upward install the gasket 1 and the timing chain tensioner 2 and tighten the bolt 3 to the specified torque c Release the screwdriver check the tensioner rod to come out and tighten the gasket 4 and the cap bolt...

Page 88: ...ncer Refer to EXHAUST PIPE AND SILENCER section Radiator hose 1 Disconnect at cylinder head side Carburetor Refer to CARBURETOR section Camshaft Refer to CAMSHAFTS section Upper engine bracket Refer to ENGINE REMOVAL section 1 Radiator pipe 1 2 Oil delivery pipe 1 3 Nut 2 4 Bolt L 135 mm 5 31 in 2 5 Bolt L 145 mm 5 71 in 2 6 Cylinder head 1 7 Timing chain guard exhaust side 1 ...

Page 89: ...d several times INSTALLING THE CYLINDER HEAD 1 Install Dowel pin 1 Cylinder head gasket 2 Timing chain guide exhaust side 3 Cylinder head 4 While pulling up the timing chain in stall the timing chain guide exhaust side and cylinder head 2 Install Washer 1 Cable guide 2 Bolts L 145 mm 5 71 in 3 Bolts L 135 mm 5 31 in 4 Nuts 5 Apply the molybdenum disulfide grease on the thread and contact surface o...

Page 90: ...me Q ty Remarks Cylinder head Refer to CYLINDER HEAD section 1 Valve lifter 5 Refer to removal section 2 Adjusting pad 5 Refer to removal section 3 Valve cotter 10 Refer to removal section 4 Valve spring retainer 5 5 Valve spring 5 6 Valve stem seal 5 7 Valve spring seat 5 8 Exhaust valve 2 9 Intake valve 3 ...

Page 91: ...r to 100 C 212 F a Remove the valve guide using a valve guide remover 1 b Install the new valve guide using a valve guide remover 1 and valve guide installer 2 c After installing the valve guide bore the valve guide using a valve guide reamer 3 to obtain proper stem to guide clearance After replacing the valve guide reface the valve seat 3 Inspect Valve face Pitting wear Grind the face Valve stem ...

Page 92: ...ompound enter the gap between the valve stem and the guide b Apply molybdenum disulfide oil to the valve stem c Install the valve into the cylinder head d Turn the valve until the valve face and valve seat are evenly pol ished then clean off all of the compound For best lapping results lightly tap the valve seat while rotating the valve back and forth between your hands e Apply a fine lapping comp...

Page 93: ...rger pitch d facing upward e Smaller pitch 3 Install Valve cotter While compressing the valve spring with a valve spring compressor 1 in stall the valve cotters 4 To secure the valve cotters onto the valve stem lightly tap the valve tip with a piece of wood Hitting the valve tip with excessive force could damage the valve 5 Install Adjusting pad 1 Valve lifter 2 Apply the molybdenum disulfide oil ...

Page 94: ...STON Order Part name Q ty Remarks Cylinder head Refer to CYLINDER HEAD section 1 Bolt cylinder 1 2 Cylinder 1 3 Piston pin clip 2 Refer to removal section 4 Piston pin 1 Refer to removal section 5 Piston 1 Refer to removal section 6 Piston ring set 1 Refer to removal section ...

Page 95: ...he piston bottom edge d If out of specification replace the piston and piston rings as a set e Calculate the piston to cylinder clearance with following formula f If out of specification replace the cylinder and replace the piston and piston rings as set CHECKING THE PISTON RING 1 Measure Ring side clearance Use a feeler gauge 1 Out of specification Replace the piston and rings as a set Clean carb...

Page 96: ...n ring end gaps as shown a Top ring end b 2nd ring end c Oil ring end upper d Oil ring e Oil ring end lower 3 Install Piston 1 Piston pin 2 Piston pin clip 3 Apply engine oil onto the piston pin and piston Be sure that the arrow mark a on the piston points to the exhaust side of the engine Before installing the piston pin clip cover the crankcase with a clean rag to prevent the piston pin clip fro...

Page 97: ...e hand while compressing the piston rings with the other hand Pass the timing chain 3 through the timing chain cavity Be careful not to damage the tim ing chain guide 4 during instal lation 4 Install Bolt cylinder 5 Bolt cylinder 10 Nm 1 0 m kg 7 2 ft lb ...

Page 98: ...NE OIL section in the CHAPTER 3 Brake pedal Refer to ENGINE REMOVAL section Clutch cable Disconnect at engine side 1 Clutch cover 1 2 Clutch spring 5 3 Pressure plate 1 4 Push rod 1 1 5 Circlip 1 6 Washer 1 7 Bearing 1 8 Ball 1 9 Push rod 2 1 10 Friction plate 9 11 Clutch plate 8 12 Cushion spring 1 13 Seat plate 1 ...

Page 99: ...t clutch boss 1 Refer to removal section 15 Lock washer 1 Refer to removal section 16 Clutch boss 1 Refer to removal section 17 Thrust washer 1 18 Primary driven gear 1 19 Push lever shaft 1 Order Part name Q ty Remarks ...

Page 100: ...asure at all four points CHECKING THE CLUTCH PLATES 1 Measure Clutch plate warpage Out of specification Replace clutch plate as a set Use a surface plate 1 and thick ness gauge 2 CHECKING THE PUSH LEVER SHAFT 1 Inspect Push lever shaft 1 Wear damage Replace CHECKING THE PUSH ROD 1 Inspect Push rod 1 1 Bearing 2 Washer 3 Push rod 2 4 Ball 5 Wear damage bend Replace INSTALLING THE PUSH LEVER SHAFT 1...

Page 101: ...l the clutch plates and friction plates alternately on the clutch boss starting with a friction plate and ending with a friction plate Apply the engine oil on the friction plates and clutch plates Unlike the clutch plate 2 the clutch plate 1 has no surface gloss Use the clutch plate 1 for the first while paying attention to the difference in surface gloss 6 Install Bearing 1 Washer 2 Circlip 3 To ...

Page 102: ...4 33 CLUTCH 11 Install Clutch cover 1 Bolt clutch cover Tighten the bolts in stage using a crisscross pattern Bolt clutch cover 10 Nm 1 0 m kg 7 2 ft lb ...

Page 103: ... the coolant Refer to CHANGING THE COOLANT sec tion in the CHAPTER 3 Radiator hose 3 Disconnect at water pump side Exhaust pipe Refer to EXHAUST PIPE AND SILENCER section Brake pedal Refer to ENGINE REMOVAL section Right engine guard 1 Oil filter element cover 1 2 Oil filter element 1 3 Water pump housing 1 4 Oil delivery pipe 1 5 Bolt oil hose 1 6 Kickstarter crank 1 7 Right crankcase cover 1 8 I...

Page 104: ...TER ELEMENT AND WATER PUMP 9 Washer 1 Refer to removal section 10 Impeller shaft 1 Refer to removal section 11 Oil seal 2 Refer to removal section 12 Bearing 1 Refer to removal section Order Part name Q ty Remarks ...

Page 105: ... damage Replace CHECKING THE BEARING 1 Inspect Bearing Rotate inner race with a finger Rough spot seizure Replace CHECKING THE OIL SEAL 1 Inspect Oil seal 1 Wear damage Replace INSTALLING THE OIL SEAL 1 Install Oil seal 1 Apply the lithium soap base grease on the oil seal lip Install the oil seal with its manufac ture s marks or numbers facing the right crankcase cover 2 2 Install Bearing 1 Instal...

Page 106: ...ct the crankcase cover when it is pulled 2 Install Oil hose 1 Bolt oil hose 2 3 Install Copper washer 1 Oil delivery pipe 2 Union bolt M8 3 Union bolt M10 4 INSTALLING THE WATER PUMP HOUSING 1 Install Dowel pin 1 O ring 2 Apply the lithium soap base grease on the O ring 2 Install Water pump housing 1 Bolt water pump housing 2 INSTALLING THE OIL FILTER ELEMENT 1 Install Oil filter element 1 O ring ...

Page 107: ...OIL FILTER ELEMENT AND WA TER PUMP section Stator Refer to CDI MAGNETO section 1 Nut primary drive gear 1 Refer to removal section 2 Nut balancer shaft driven gear 1 Refer to removal section 3 Lock washer 1 4 Primary drive gear 1 5 Balancer shaft drive gear 1 6 Lock washer 1 7 Balancer shaft driven gear 1 8 Balancer shaft 1 Refer to removal section ...

Page 108: ...n the center a of the balancer shaft weight along the line connect ing the centers of the crankshaft and balancer shaft 2 Install Balancer shaft driven gear 1 Install the balancer shaft driven gear onto the balancer shaft while aligning the punch mark a on the balancer shaft driven gear with the lower spline b on the balancer shaft end 3 Install Balancer shaft drive gear 1 Align the punched mark a...

Page 109: ...on Right crankcase cover Refer to OIL FILTER ELEMENT AND WA TER PUMP section 1 Circlip 1 2 Washer 1 3 Oil pump drive gear 1 4 Oil pump assembly 1 5 Outer rotor 2 1 6 Circlip 1 7 Inner rotor 2 1 8 Dowel pin 1 9 Oil pump cover 1 10 Outer rotor 1 1 11 Inner rotor 1 1 12 Dowel pin 1 13 Washer 1 14 Oil pump drive shaft 1 ...

Page 110: ...4 41 OIL PUMP 15 Rotor housing 1 Order Part name Q ty Remarks ...

Page 111: ...G THE OIL TANK Order Part name Q ty Remarks Drain the engine oil Refer to CHANGING THE ENGINE OIL section in the CHAPTER 3 1 Oil hose 2 1 2 Oil hose 1 1 3 Dowel pin 2 4 Oil tank breather hose 1 5 Oil tank 1 6 Oil strainer 1 ...

Page 112: ... rotor 1 1 Apply the engine oil on the outer rotor 1 3 Install Oil pump cover 1 Screw oil pump cover 2 Dowel pin 3 Inner rotor 2 4 Circlip 5 Apply the engine oil on the inner ro tor 2 Fit the dowel pin into the groove in the inner rotor 2 4 Install Outer rotor 2 1 Dowel pin 2 Oil pump assembly 3 Bolt oil pump assembly L 25 mm 0 94 in 4 Bolt oil pump assembly L 30 mm 1 18 in 5 Apply the engine oil ...

Page 113: ...section 1 Kick idle gear 1 2 Kick shaft assembly 1 Refer to removal section 3 Spring guide 1 4 Torsion spring 1 5 Ratchet wheel 1 6 Kick gear 1 7 Kick shaft 1 8 Washer 1 9 Shift pedal 1 10 Shift shaft 1 11 Collar 1 12 Torsion spring 1 13 Roller 1 14 Shift guide 1 Refer to removal section 15 Shift lever assembly 1 Refer to removal section 16 Shift lever 1 ...

Page 114: ...4 45 KICK SHAFT AND SHIFT SHAFT 17 Pawl 2 18 Pawl pin 2 19 Spring 2 20 Bolt stopper lever 1 21 Stopper lever 1 22 Torsion spring 1 23 Segment 1 Refer to removal section Order Part name Q ty Remarks ...

Page 115: ...CKING THE KICK GEAR KICK IDLE GEAR AND RATCHET WHEEL 1 Inspect Kick gear 1 Kick idle gear 2 Ratchet wheel 3 Gear teeth a Ratchet teeth b Wear damage Replace CHECKING THE SHIFT SHAFT 1 Inspect Shift shaft 1 Bend damage Replace Spring 2 Broken Replace CHECKING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY 1 Inspect Shift guide 1 Shift lever 2 Pawl 3 Pawl pin 4 Spring 5 Wear damage Replace CHECKING THE ST...

Page 116: ...MBLY 1 Install Kick gear 1 Washer 2 Circlip 3 Ratchet wheel 4 Spring 5 Washer 6 Circlip 7 To kick shaft 8 Apply the molybdenum disulfide oil on the inner circumferences of the kick gear and ratchet wheel Align the punch mark a on the ratchet wheel with the punch mark b on the kick shaft 2 Install Torsion spring 1 To kick shaft 2 Make sure the stopper a of the tor sion spring fits into the hole b o...

Page 117: ...on spring clockwise and hook into the proper hole a in the crankcase INSTALLING THE KICK IDLE GEAR 1 Install Kick idle gear 1 Washer 2 Circlip 3 Apply the engine oil on the kick idle gear inner circumference Install the kick idle gear with its de pressed side a toward you ...

Page 118: ...s Seat and fuel tank Refer to SEAT FUEL TANK AND SIDE COVERS section Disconnect the CDI magneto lead Shift pedal Refer to KICK SHAFT AND SHIFT SHAFT section 1 Left crankcase cover 1 2 Nut rotor 1 Refer to removal section 3 Rotor 1 Refer to removal section 4 Stator 1 5 Woodruff key 1 ...

Page 119: ...d portions of the crankshaft and rotor When installing the woodruff key make sure that its flat surface a is in parallel with the crankshaft center line b When installing the rotor align the keyway c of the rotor with the woodruff key 3 Install Washer 1 Nut rotor 2 Use the rotor holding tool 3 4 Connect CDI magneto lead Refer to CABLE ROUTING DIA GRAM section in the CHAPTER 2 5 Install Dowel pin G...

Page 120: ...ection Exhaust pipe and silencer Refer to EXHAUST PIPE AND SILENCER section Clutch cable Disconnect at the engine side Radiator Refer to RADIATOR section Shift pedal Refer to KICK SHAFT AND SHIFT SHAFT section Cylinder head breather hose Refer to CAMSHAFTS section Drain the engine oil Refer to CHANGING THE ENGINE OIL section in the CHAPTER 3 Oil hose and oil tank breather hose Refer to OIL PUMP se...

Page 121: ...oval section 5 Lock washer 1 Refer to removal section 6 Drive sprocket 1 Refer to removal section 7 Clip 1 8 Bolt brake pedal 1 9 Brake pedal 1 10 Upper engine bracket 2 11 Lower engine bracket 2 12 Engine mounting bolt 3 13 Pivot shaft 1 Refer to removal section 14 Engine 1 Refer to removal section Order Part name Q ty Remarks ...

Page 122: ...et 4 Bolt lower engine bracket 5 Patch 6 Engine mounting bolt front 7 Upper engine bracket 8 Bolt upper engine bracket 9 Engine mounting bolt upper 10 Lower engine guard 11 Bolt lower engine guard 12 Apply the molybdenum disulfide grease on the pivot shaft Install the patch with the claw a facing outside the chassis INSTALLING THE BRAKE PEDAL 1 Install Spring 1 Brake pedal 2 O ring 3 Bolt brake pe...

Page 123: ...e chain sprocket cov er 3 INSTALLING THE NEUTRAL SWITCH 1 Install Spring 1 Pin 2 O ring 3 Neutral switch 4 Screw neutral switch 5 Apply the lithium soap base grease on the O ring 2 Install Hose guide cylinder head breath er hose 1 Bolt hose guide 2 Nut drive sprocket 75 Nm 7 5 m kg 54 ft lb Screw drive chain sprocket cover 8 Nm 0 8 m kg 5 8 ft lb Screw neutral switch 4 Nm 0 4 m kg 2 9 ft lb Bolt h...

Page 124: ... KICK SHAFT AND SHIFT SHAFT section Stator Refer to CDI MAGNETO section Balancer shaft Refer to BALANCER section 1 Timing chain guide intake side 1 2 Timing chain 1 3 Oil delivery pipe 2 1 4 Bolt L 45 mm 1 77 in 6 Refer to removal section 5 Bolt L 55 mm 2 17 in 1 Refer to removal section 6 Bolt L 70 mm 2 76 in 4 Refer to removal section 7 Hose guide 1 Refer to removal section 8 Clutch cable holder...

Page 125: ...4 56 CRANKCASE AND CRANKSHAFT 10 Left crankcase 1 Refer to removal section 11 Oil strainer 1 12 Crankshaft 1 Refer to removal section Order Part name Q ty Remarks ...

Page 126: ...CRANKCASE BEARING Order Part name Q ty Remarks Transmission Refer to TRANSMISSION SHIFT CAM AND SHIFT FORK section Shift cam and shift fork Refer to TRANSMISSION SHIFT CAM AND SHIFT FORK section 1 Oil seal 2 2 Bearing 10 Refer to removal section ...

Page 127: ...2 Do not use a hammer to drive out the crankshaft REMOVING THE CRANKCASE BEARING 1 Remove Bearing 1 Remove the bearing from the crankcase by pressing its inner race Do not use the removed bearing CHECKING THE TIMING CHAIN AND TIMING CHAIN GUIDE 1 Inspect Timing chain Cracks stiff Replace the timing chain and camshaft sprocket as a set 2 Inspect Timing chain guide Wear damage Replace CHECKING THE C...

Page 128: ... center with one hand while turning the nut of the installing tool with the other Operate the installing tool un til the crankshaft bottoms against the bearing Before installing the crankshaft clean the contacting surface of crankcase Do not use a hammer to drive in the crankshaft A For USA and CDN B Except for USA and CDN 2 Check Shifter operation Transmission operation Unsmooth operation Repair ...

Page 129: ...crankcase tightening bolts in stage using a crisscross pat tern 7 Install Oil delivery pipe 2 1 O ring 2 Bolt oil delivery pipe 2 3 Apply the lithium soap base grease on the Orings 8 Install Timing chain 1 Timing chain guide intake side 2 Bolt timing chain guide 3 9 Remove Sealant Forced out on the cylinder mating surface 10 Apply Engine oil To the crank pin bearing and oil delivery hole 11 Check ...

Page 130: ...s Engine Refer to ENGINE REMOVAL section Separate the crankcase Refer to CRANKCASE AND CRANK SHAFT section 1 Main axle 1 Refer to removal section 2 Drive axle 1 Refer to removal section 3 Shift cam 1 Refer to removal section 4 Shift fork 3 1 Refer to removal section 5 Shift fork 2 1 Refer to removal section 6 Shift fork 1 1 Refer to removal section 7 Collar 1 ...

Page 131: ... Re place 2 Inspect Shift cam 1 Segment 2 Wear damage Replace 3 Check Shift fork movement Unsmooth operation Replace shift fork For a malfunctioning shift fork re place not only the shift fork itself but the two gears each adjacent to the shift fork INSTALLING THE TRANSMISSION 1 Install 5th pinion gear 24T 1 3rd pinion gear 20T 2 Collar 3 4th pinion gear 22T 4 2nd pinion gear 16T 5 To main axle 6 ...

Page 132: ...t fork 3 R 3 Shift cam 4 To main axle and drive axle Apply the molybdenum disulfide oil on the shift fork grooves Mesh the shift fork 1 L with the 4th wheel gear 5 and 3 R with the 5th wheel gear 7 on the drive axle Mesh the shift fork 2 C with the 3rd pinion gear 6 on the main ax le 6 Install Transmission assembly 1 To left crankcase 2 Apply the engine oil on the bearings and guide bars 7 Check S...

Page 133: ... Order Part name Q ty Remarks Hold the machine by placing the suitable stand under the engine Refer to HANDLING NOTE 1 Bolt axle holder 4 Only loosening 2 Nut front wheel axle 1 3 Front wheel axle 1 4 Front wheel 1 5 Collar 2 6 Oil seal 2 7 Bearing 2 Refer to removal section 8 Brake disc 1 5 ...

Page 134: ...achine by placing the suitable stand under the engine Refer to HANDLING NOTE 1 Nut rear wheel axle 1 2 Rear wheel axle 1 3 Drive chain puller 2 4 Rear wheel 1 Refer to removal section 5 Collar 2 6 Rear wheel sprocket 1 7 Oil seal 2 8 Circlip 1 9 Bearing 2 Refer to removal section 10 Brake disc 1 ...

Page 135: ...eflection only rear brake disc Use the dial gauge 1 Out of specification Inspect wheel runout If wheel runout is in good condi tion replace the brake disc 2 Measure Brake disc thickness a Out of limit Replace INSTALLING THE FRONT WHEEL 1 Install Bearing left 1 Spacer 2 Bearing right 3 Oil seal 4 Apply the lithium soap base grease on the bearing and oil seal lip when installing Use a socket that ma...

Page 136: ...the lithium soap base grease on the bearing and oil seal lip when installing Install the bearing with seal facing outward Use a socket that matches the out side diameter of the race of the bearing Right side of bearing shall be in stalled first Install the oil seal with its manufac ture s marks or numbers facing out ward Do not strike the inner race of the bearing Contact should be made only with ...

Page 137: ...el axle 2 Install the left drive chain puller and insert the wheel axle from left side Apply the lithium soap base grease on the wheel axle 8 Install Right drive chain puller 1 Washer 2 Nut wheel axle 3 Temporarily tighten the nut wheel axle at this point 9 Adjust Drive chain slack a Refer to ADJUSTING THE DRIVE CHAIN SLACK section in the CHAPTER 3 10 Tighten Nut wheel axle 1 Locknut 2 Drive chain...

Page 138: ...tand under the engine Refer to HANDLING NOTE Drain the brake fluid Refer to removal section 1 Brake hose holder protector 2 2 Union bolt 2 3 Brake hose 1 4 Pad pin plug 1 Remove when loosening the pad pin 5 Pad pin 1 Loosen when disassembling the brake cali per 6 Brake caliper 1 7 Brake lever 1 8 Brake master cylinder bracket 1 9 Brake master cylinder 1 ...

Page 139: ...ne Refer to HANDLING NOTE Rear wheel Refer to FRONT WHEEL AND REAR WHEEL section Drain the brake fluid Refer to removal section 1 Brake pedal 1 2 Brake master cylinder 1 3 Brake hose holder 2 4 Union bolt 2 5 Brake hose 1 6 Pad pin plug 1 Remove when loosening the pad pin 7 Pad pin 1 Loosen when disassembling the brake cali per 8 Brake caliper 1 ...

Page 140: ...rder Part name Q ty Remarks A Front B Rear A B 1 Pad pin 1 1 2 Brake pad 2 2 3 Pad support 1 1 4 Brake caliper piston 2 1 Refer to removal section 5 Brake caliper piston dust seal 2 1 Refer to removal section 6 Brake caliper piston seal 2 1 Refer to removal section ...

Page 141: ...LINDER Order Part name Q ty Remarks A Front B Rear 1 Brake master cylinder cap 1 2 Diaphragm 1 3 Reservoir float 1 4 Push rod Front 1 5 Brake master cylinder boot 1 6 Circlip 1 Use a long nose circlip pliers 7 Washer 1 8 Push rod Rear 1 9 Brake master cylinder kit 1 ...

Page 142: ...l steps a Insert a piece of rag into the brake caliper to lock one brake caliper b Carefully force the piston out of the brake caliper cylinder with compressed air A Front B Rear REMOVING THE BRAKE CALIPER PISTON SEAL KIT 1 Remove Brake caliper piston dust seal 1 Brake caliper piston seal 2 Remove the brake caliper piston seals and brake caliper piston dust seals by pushing them with a finger Neve...

Page 143: ...on Clean them with brake fluid 2 Install Brake caliper piston seal 1 Brake caliper piston dust seal 2 Always use new brake caliper pis ton seals and brake caliper piston dust seals Apply the brake fluid on the brake caliper piston seal Apply the silicone grease on the brake caliper piston dust seal Fit the brake caliper piston seals and brake caliper piston dust seals onto the slot on brake calipe...

Page 144: ...ng installation cause improper brake performance 3 Install Spring 1 To brake master cylinder piston 2 Install the spring at the smaller dia side 4 Install Brake master cylinder kit 1 Washer front brake 2 Push rod rear brake 2 Circlip 3 Brake master cylinder boot 4 Push rod front brake 5 To brake master cylinder Apply the brake fluid on the brake master cylinder kit Apply the silicone grease on the...

Page 145: ...4 Install Pin 1 Washer 2 Cotter pin 3 After installing check the brake pedal height Refer to ADJUSTING THE REAR BRAKE section in the CHAP TER 3 INSTALLING THE FRONT BRAKE HOSE 1 Install Copper washer 1 Brake hose 2 Union bolt 3 Always use new copper washers Install the brake hose so that its pipe portion a directs as shown and lightly touches the projection b on the brake caliper 2 Install Brake h...

Page 146: ... fluid mixing fluids may result in a harmful chemical reaction and lead to poor performance Be careful that water does not enter the master cylinder when refilling Water will significantly lower the boiling point of the flu id and may result in vapor lock Brake fluid may erode painted sur faces or plastic parts Always clean up spilled fluid immediately A Front B Rear 2 Air bleed Brake system Refer...

Page 147: ...5 15 FRONT BRAKE AND REAR BRAKE A Front B Rear 5 Install rear brake only Protector 1 Bolt protector 2 Bolt protector 7 Nm 0 7 m kg 5 1 ft lb ...

Page 148: ...Refer to FRONT BRAKE AND REAR BRAKE section Number plate Refer to SEAT FUEL TANK AND SIDE COVERS section in the CHAPTER 4 1 Protector 1 2 Pinch bolt upper bracket 2 Only loosening 3 Damper assembly 1 Loosen when disassembling the front fork Refer to removal section 4 Pinch bolt lower bracket 2 Only loosening 5 Front fork 1 21 Nm 2 1 m kg 15 ft lb 21 Nm 2 1 m kg 15 ft lb 5 Nm 0 5 m kg 3 6 ft lb 5 N...

Page 149: ... Stopper ring 1 Refer to removal section 5 Inner tube 1 Refer to removal section 6 Outer tube 1 7 Piston metal 1 8 Slide metal 1 9 Oil seal washer 1 10 Oil seal 1 11 Base valve 1 Drain the fork oil Refer to removal section 12 Damper assembly 1 Drain the fork oil Refer to removal section 30 Nm 3 0 m kg 22 ft lb 29 Nm 2 9 m kg 21 ft lb 29 Nm 2 9 m kg 21 ft lb 1 Nm 0 1 m kg 0 7 ft lb 55 Nm 5 5 m kg 4...

Page 150: ...n the inner tube and locknut 3 Hold the locknut and remove the adjuster Do not remove the locknut as the damper rod may go into the damp er assembly and not be taken out REMOVING THE INNER TUBE 1 Remove Dust seal 1 Stopper ring 2 Using slotted head screwdriver Take care not to scratch the inner tube 2 Remove Inner tube 1 Oil seal removal steps a Push in slowly a the inner tube just before it botto...

Page 151: ...r damage Re place CHECKING THE ADJUSTER 1 Inspect Adjuster 1 O ring 2 Wear damage Replace ASSEMBLING THE FRONT FORK 1 Wash the all parts in a clean sol vent 2 Stretch the damper assembly ful ly 3 Fill Front fork oil 1 To damper assembly Be sure to use recommended fork oil If other oils are used they may have an excessively ad verse effect on the front fork per formance Never allow foreign material...

Page 152: ...y up and down more than 10 times to distribute the fork oil 12 While protecting the damper as sembly 1 with a rag and com pressing fully allow excessive oil to overflow on the base valve side Take care not to damage the damp er assembly 13 Allow the overflowing oil to es cape at the hole a in the damper assembly 14 Check Damper assembly smooth move ment Tightness binding rough spots Repeat the ste...

Page 153: ... dia end a facing the fork spring 25 Install Damper assembly 1 To inner tube 2 To install the damper assembly into the inner tube hold the inner tube aslant If the inner tube is held vertically the damper assembly may fall into it damaging the valve inside 26 Loosen Rebound damping adjuster 1 Loosen the rebound damping ad juster finger tight Record the set position of the ad juster the amount of t...

Page 154: ...on the front fork per formance Never allow foreign materials to enter the front fork 32 Install Damper assembly 1 To outer tube Temporarily tighten the damper as sembly 33 Install Protector guide 1 INSTALLING THE FRONT FORK 1 Install Front fork 1 Temporarily tighten the pinch bolts lower bracket Do not tighten the pinch bolts up per bracket yet 2 Tighten Damper assembly 1 Use the cap bolt ring wre...

Page 155: ...1 Bolt protector 2 6 Adjust Rebound damping force Turn in the damping adjuster 1 fin ger tight and then turn out to the orig inally set position 7 Adjust Compression damping force Turn in the damping adjuster 1 fin ger tight and then turn out to the orig inally set position Pinch bolt upper brack et 21 Nm 2 1 m kg 15 ft lb Pinch bolt lower brack et 21 Nm 2 1 m kg 15 ft lb Bolt protector 5 Nm 0 5 m...

Page 156: ...ver side 4 Clutch lever holder 1 5 Engine stop switch 1 6 Brake master cylinder 1 Refer to removal section 7 Throttle cable cap 1 8 Throttle cable 1 pulled 1 Disconnect at the throttle side 9 Throttle cable 2 pushed 1 Disconnect at the throttle side 10 Right grip 1 Refer to removal section 11 Tube guide 1 12 Collar 1 13 Left grip 1 Refer to removal section 14 Handlebar upper holder 2 15 Handlebar ...

Page 157: ...holder Installing the handlebar lower hold er in the reverse direction allows the front to rear offset amount of the handlebar position to be changed Do not tighten the nut yet 2 Install Handlebar 1 Handlebar upper holder 2 Bolt handlebar upper holder 3 The handlebar upper holder should be installed with the punched mark a forward Install the handlebar so that the marks b are in place on both side...

Page 158: ... throttle cable cap 2 10 Install Brake master cylinder 1 Brake master cylinder bracket 2 Bolt brake master cylinder brack et 3 Install the bracket so that the arrow mark a faces upward First tighten the bolt on the upper side of the brake master cylinder bracket and then tighten the bolt on the lower side 11 Install Engine stop switch 1 Clutch lever holder 2 Bolt clutch lever holder 3 Hot starter ...

Page 159: ...EBAR 13 Adjust Clutch lever free play Refer to ADJUSTING THE CLUTCH CABLE FREE PLAY section in the CHAPTER 3 Hot starter lever free play Refer to ADJUSTING THE HOT STARTER LEVER FREE PLAY section in the CHAPTER 3 ...

Page 160: ...the suitable stand under the engine Refer to HANDLING NOTE Number plate Refer to SEAT FUEL TANK AND SIDE COVERS section in the CHAPTER 4 Handlebar Refer to HANDLEBAR section Front fender 1 Steering stem nut 1 2 Front fork 2 Refer to FRONT FORK section 3 Upper bracket 1 4 Steering ring nut 1 Refer to removal section 5 Lower bracket 1 6 Bearing race cover 1 7 Upper bearing 1 8 Lower bearing 1 Refer ...

Page 161: ...5 29 STEERING 9 Bearing race 2 Refer to removal section Order Part name Q ty Remarks ...

Page 162: ...ring races Spin the bearings by hand If the bearings hang up or are not smooth in their operation in the bearing races replace bearings and bearing races as a set INSTALLING THE LOWER BRACKET 1 Install Lower bearing 1 Apply the lithium soap base grease on the dust seal lip and bearing inner circumference 2 Install Bearing race Upper bearing 1 Bearing race cover 2 Apply the lithium soap base grease...

Page 163: ... If not adjust the steering by loosen ing the steering ring nut little by lit tle 10 Adjust Front fork top end a 11 Tighten Pinch bolt upper bracket 1 Pinch bolt lower bracket 2 Tighten the lower bracket to speci fied torque If torqued too much it may cause the front fork to mal function Steering stem nut 145 Nm 14 5 m kg 105 ft lb Front fork top end stan dard a 5 mm 0 20 in Pinch bolt upper brack...

Page 164: ...ING NOTE Brake hose holder Refer to FRONT BRAKE AND REAR BRAKE section Rear brake caliper Refer to FRONT BRAKE AND REAR BRAKE section Bolt brake pedal Shift the brake pedal backward Drive chain 1 Drive chain support 1 2 Lower chain tensioner 1 3 Bolt rear shock absorber relay arm 1 Hold the swingarm 4 Bolt connecting rod 1 5 Pivot shaft 1 6 Swingarm 1 ...

Page 165: ...EMBLING THE SWINGARM Order Part name Q ty Remarks 1 Cap 2 Refer to removal section 2 Relay arm 1 3 Connecting rod 1 4 Collar 2 5 Oil seal 2 6 Thrust bearing 2 7 Bushing 2 8 Oil seal 8 9 Bearing 10 Refer to removal section ...

Page 166: ...l seal 3 Damage Replace INSTALLING THE BEARING AND OIL SEAL 1 Install Bearing 1 Oil seal 2 To swingarm Apply the molybdenum disulfide grease on the bearing when install ing Install the bearing by pressing it on the side having the manufacture s marks or numbers First install the outer and then the inner bearings to a specified depth from inside 2 Install Bearing 1 Washer 2 Oil seal 3 To relay arm ...

Page 167: ...olybdenum disulfide grease on the bolt circumference and threaded portion Do not tighten the nut yet 6 Install Swingarm 1 Pivot shaft 2 Apply the molybdenum disulfide grease on the pivot shaft Insert the pivot shaft from right side 7 Check Swingarm side play a Free play exists Replace thrust bearing Swingarm up and down move ment b Unsmooth movement binding rough spots Grease or replace bearings b...

Page 168: ...t lower chain tensioner 5 14 Install Drive chain support 1 Drive chain support cover 2 Bolt drive chain support L 50 mm 1 97 in 3 Nut drive chain support 4 Bolt drive chain support cover L 10 mm 0 39 in 5 Nut relay arm 70 Nm 7 0 m kg 50 ft lb Nut lower chain tension er 16 Nm 1 6 m kg 11 ft lb Nut drive chain sup port 7 Nm 0 7 m kg 5 1 ft lb Bolt drive chain support cover 7 Nm 0 7 m kg 5 1 ft lb ...

Page 169: ...SIDE COVERS section in the CHAPTER 4 Silencer Refer to EXHAUST PIPE AND SILENCER section in the CHAPTER 4 1 Clamp air filter joint 1 Only loosening 2 Rear frame 1 3 Bolt rear shock absorber relay arm 1 Hold the swingarm 4 Bolt rear shock absorber frame 1 5 Rear shock absorber 1 6 Locknut 1 Only loosening 7 Adjuster 1 Only loosening 8 Spring seat 2 9 Lower spring guide 1 10 Upper spring guide 1 11 ...

Page 170: ...5 38 REAR SHOCK ABSORBER 12 Bearing 2 Refer to removal section Order Part name Q ty Remarks ...

Page 171: ... sorber be sure to extract the nitrogen gas from valve 1 Wear eye protec tion to prevent eye damage from es caping gas and or metal chips To dispose of a damaged or worn out rear shock absorber take the unit to your Yamaha dealer for this disposal procedure REMOVING THE BEARING 1 Remove Stopper ring upper bearing 1 Press in the bearing while pressing its outer race and remove the stopper ring 2 Re...

Page 172: ...disulfide grease on the dust seal lips and col lars Apply the lithium soap base grease on the O rings 2 Install Bushing 1 Collar 2 Dust seal 3 Apply the molybdenum disulfide grease on the bearing and dust seal lips Install the dust seals with their lips facing outward 3 Install Rear shock absorber 4 Install Bolt rear shock absorber frame 1 Washer 2 Nut rear shock absorber frame 3 Apply the molybde...

Page 173: ...5 41 REAR SHOCK ABSORBER Bolt rear frame lower 3 7 Tighten Bolt air filter joint 1 Bolt rear frame lower 32 Nm 3 2 m kg 23 ft lb Bolt air filter joint 3 Nm 0 3 m kg 2 2 ft lb ...

Page 174: ...le position sensor 3 Neutral switch 4 CDI magneto 5 Ignition coil 6 Spark plug 7 CDI unit COLOR CODE B Black Br Brown G Green L Blue O Orange P Pink R Red Sb Sky blue W White Y Yellow B L Black Blue B W Black White B Y Black Yellow G B Green Black L W Blue White R W Red White B W B W B L B Y Sb Sb G B L Y L Y P B B B B G O W R P G W R P B Br W W B Y G Br G R R O B Sb Sb Y Y W Y W G G B P P Br Br R...

Page 175: ... following special tools in this inspection Spark gap test Spark Clean or replace spark plug No spark Check entire ignition system for connection couplers leads and ignition coil No good Repair or replace OK Check engine stop switch No good Replace OK Check ignition coil primary coil and secondary coil No good Replace OK Check CDI magneto pickup coil and charging coil No good Replace OK Check neut...

Page 176: ...emove the ignition coil cap 2 Inspect Primary coil resistance Out of specification Replace 3 Inspect Secondary coil resistance Out of specification Replace 4 Inspect Sealed portion of ignition coil a Spark plug terminal pin b Threaded portion of spark plug c Wear Replace CHECKING THE CDI MAGNETO 1 Inspect Pickup coil resistance Out of specification Replace 2 Inspect Charging coil 1 resistance Out ...

Page 177: ... engaged Re place Set the tester selection position to Ω 1 CHECKING THE CDI UNIT Check all electrical components If no fault is found replace the CDI unit Then check the electrical compo nents again Tester lead Pink lead 1 Tester lead Black lead 2 Charging coil 2 resis tance Tester se lector posi tion 44 66 Ω at 20 C 68 F Ω 10 Tester lead Sky blue lead 1 Tester lead Ground 2 Result Conductive whil...

Page 178: ... IGNITION SYSTEM section Use the following special tools in this inspection Check entire ignition system for connection No good Repair or replace OK Check throttle position sensor Throttle position sensor coil No good Replace OK Check CDI magneto Charging coil No good Replace OK Check CDI unit Throttle position sensor input voltage No good Replace Pocket tester YU 3112 C 90890 03112 ...

Page 179: ...sition sensor 1 Screw throttle position sensor 2 Align the slot a in the throttle posi tion sensor with the projection b on the carburetor Temporarily tighten the screw throttle position sensor 5 Install Carburetor Throttle position sensor coupler 6 Adjust Engine idling speed Refer to ADJUSTING THE EN GINE IDLING SPEED section in the CHAPTER 3 7 Insert the thin electric conductors 2 lead into the ...

Page 180: ...1 Tighten the screw throttle position sensor using the T25 bit 14 Install the carburetor CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE 1 Disconnect the throttle position sensor coupler 2 Start the engine 3 Inspect Throttle position sensor input volt age Out of specification Replace the CDI unit Throttle po sition sen sor output voltage Tester se lector posi tion 0 58 0 78 V DCV Tester lead B...

Page 181: ...essarily Otherwise too much fuel may be discharged starting may become difficult or the engine may not run well After installing the carburetor check that the throttle operates correctly and opens and closes smoothly ATMOSPHERIC CONDITIONS AND CARBURETOR SETTINGS The air density i e concentration of oxygen in the air determines the rich ness or leanness of the air fuel mix ture Higher temperature ...

Page 182: ...THE JET NEEDLE The jet needle is adjusted by chang ing it The jet needle setting parts having the same taper angle are available in different straight portion diameters and in different taper starting posi tions a Diameter of the straight por tion b Reference needle c 0 5 leaner Changing from NFPR 5 to NFLR 5 has the same effect as a lowering of 0 5 clip position Effects of changing the jet needle...

Page 183: ...an 168 4MX 14943 91 Pilot jet Size Part number Rich 48 4MX 14948 06 45 4MX 14948 05 STD 42 4MX 14948 04 40 4MX 14948 03 Lean 38 4MX 14948 02 Jet needle Size Part number Rich NFPN 5TA 14916 PN NFPP 5TA 14916 PP NFPQ 5TA 14916 P1 STD NFPR 5TA 14916 PR NFPS 5TA 14916 PS NFPT 5TA 14916 PT Lean NFPU 5TA 14916 PU Rich NFLN 5TA 14916 LN NFLP 5TA 14916 LP NFLQ 5TA 14916 L1 NFLR 5TA 14916 LR NFLS 5TA 14916...

Page 184: ...tion 1 groove down The clip position is the jet needle groove on which the clip is installed The positions are numbered from the top Check that the accelerator pump operates smoothly except for rich mixture symp tom Rich mixture Raise jet needle clip position 1 groove up 1 4 3 4 throttle Hard breathing Lack of speed Lower jet needle clip position 1 groove down 1 4 1 2 throttle Slow speed pick up P...

Page 185: ...7 5 ENGINE This should be taken simply for an example It is necessary to set the carburetor while checking the operating conditions of the engine ...

Page 186: ...der a stony or hard road condi tion the tire pressure should be higher to prevent a flat tire FRONT FORK SETTING The front fork setting should be made depending on the rider s feeling of an actual run and the circuit conditions The front fork setting includes the fol lowing three factors 1 Setting of air spring characteris tics Change the fork oil amount 2 Setting of spring preload Change the spri...

Page 187: ... bolt 2 Remove the stand or block from the engine and with a rider astride the seat measure the sunken length b between the rear wheel axle center and the rear fender holding bolt 3 Loosen the locknut 1 and make adjustment by turning the spring adjuster 2 to achieve the stan dard figure from the subtraction of the length b from the length a If the machine is new and after it is broken in the same ...

Page 188: ...ING FRE E LEN GTH ap prox S O F T 4 5 1C3 00 Green 265 4 7 1C3 10 Red 265 4 9 1C3 20 Black 265 5 1 1C3 30 Blue 265 S T D 5 3 1C3 40 1C3 A0 Yellow 275 S TI F F 5 5 1C3 50 Pink 275 5 7 1C3 60 White 275 T Y P E SPRI NG RAT E SPRING PART NUM BER 22212 I D MARK Q TY SPR ING FRE E LEN GTH 4 3 5UN 00 Brown 1 260 T Y P E SPRI NG RAT E ap prox SPRING PART NUM BER 22212 I D MARK Q TY SPR ING FRE E LEN GTH S...

Page 189: ...tire range bottoming out Compression damping Turn adjuster clockwise about 2 clicks to in crease damping Oil amount Increase oil amount by about 5 10 cm3 0 2 0 4 Imp oz 0 2 0 3 US oz Spring Replace with stiff spring Stiff toward stroke end Oil amount Decrease oil amount by about 5 cm3 0 2 Imp oz 0 2 US oz Soft toward stroke end bottoming out Oil amount Increase oil amount by about 5 cm3 0 2 Imp oz...

Page 190: ...eavy and dragging Rebound damping Turn adjuster counterclockwise about 2 clicks to decrease damping Spring Replace with soft spring Poor road gripping Rebound damping Turn adjuster counterclockwise about 2 clicks to decrease damping Low compression damping Turn adjuster clockwise about 1 clicks to in crease damping High compression damping Turn adjuster clockwise about 1 6 turn to in crease dampin...

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Page 192: ...PRINTED IN JAPAN E PRINTED ON RECYCLED PAPER YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...

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Yamaha YZ250F X 2008, Owner'S Service Manual

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