Yamaha 2011 YZ250 Owner'S Manual Download Page 75

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4-11

CARBURETOR AND REED VALVE

4. Install:

• Starter plunger "1"

5. Install:

• Pilot jet "1"
• Main jet "2"

6. Install:

• Needle valve "1"
• Float "2"
• Float pin "3"

• After installing the needle valve to

the float, install them to the carbure-
tor.

• Check the float for smooth move-

ment.

7. Install:

• Float chamber "1"
• Plate "2"
• Screw (float chamber) "3"

8. Install:

• Air vent hose [L=580 mm (22.8

in)] "1"

• Air vent hose [L=400mm (15.7 in)]

"2"

• Overflow hose [L=280mm (11.0

in)] "3"

• Clamp "4"

Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.

Install the air vent hoses and overflow
hose to the carburetor with their ends
not having the cuts "a" toward the car-
buretor.

9. Install:

• Jet needle "1"
• Collar "2"
• Spring "3"
• Needle holder "4"

To throttle valve "5".

Install the spring with its smaller dia.
"a" facing the collar.

10. Install:

• Throttle cable "1"
• Locknut "2"

• Mixing chamber top "3"
• Spring (throttle valve) "4"
• Ring "5"
• Throttle valve "6"

• While compressing the spring, con-

nect the throttle cable.

• Align the projection "a" on the ring

with the groove "b" in the needle
holder "7".

11. Install:

• Mixing chamber top "1"
• Screw (mixing chamber top) "2"

To carburetor "3".

• Insert the throttle valve into the car-

buretor body while pulling up the le-
ver "4".

• After installing, check the throttle

grip for smooth movement.

INSTALLING THE CARBURETOR

1. Install:

• Carburetor "1"

Install the projection between the car-
buretor joint slots.

2. Tighten:

• Screw (carburetor joint) "1"

Locknut:

4 Nm (0.4 m•kg, 2.9
ft•lb)

Summary of Contents for 2011 YZ250

Page 1: ...YCLED PAPER 2015 YZ250 YZ250F2 2015 q Read this manual carefully before operating this vehicle q Il convient de lire attentivement ce manuel avant la première utilisation du véhicule q Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch bevor Sie das Fahrzeug in Betrieb nehmen q Leggere attentamente questo manuale prima di utilizzare questo veicolo 1SS 28199 33_cover indd 1 2014 05 29 11 59...

Page 2: ... remis avec le véhicule en cas de vente de ce dernier Q Leggere attentamente questo manuale prima di utilizzare il veicolo Questo manuale dovrebbe accompagnare il veicolo se viene venduto Q Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch bevor Sie das Fahrzeug in Betrieb nehmen Diese Bedienungsanleitung muss wenn das Fahrzeug verkauft wird beim Fahrzeug verbleiben 1SS 28199 33_cover ind...

Page 3: ...2 2015 2015 YZ250 YZ250 1SS 28199 33 E0 1SS 28199 33 E0 OWNER S SERVICE MANUAL OWNER S SERVICE MANUAL Read this manual carefully before operating this vehicle Read this manual carefully before operating this vehicle ...

Page 4: ......

Page 5: ...ER S SERVICE MANUAL 2014 by Yamaha Motor Co Ltd 1st Edition June 2014 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: ...IS MACHINE IS TO BE OPER ATED BY AN EXPERIENCED RID ER ONLY Do not attempt to operate this ma chine at maximum power until you are totally familiar with its character istics THIS MACHINE IS DESIGNED TO BE RIDDEN BY THE OPERATOR ONLY Do not carry passengers on this machine ALWAYS WEAR PROTECTIVE APPAREL When operating this machine al ways wear an approved helmet with goggles or a face shield Also w...

Page 7: ...wn to find the required fore edge symbol mark and go to a page for required item and de scription MANUAL FORMAT All of the procedures in this manual are organized in a sequential step by step format The information has been complied to provide the me chanic with an easy to read handy reference that contains comprehen sive explanations of all disassembly repair assembly and inspection op erations I...

Page 8: ...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 Electric current A Ill...

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: ... AND MAINTENANCE 3 5 ENGINE 3 6 CHASSIS 3 10 ELECTRICAL 3 20 CHAPTER 4 ENGINE SEAT FUEL TANK AND SIDE COVERS 4 1 EXHAUST PIPE AND SILENCER 4 3 RADIATOR 4 5 CARBURETOR AND REED VALVE 4 7 CYLINDER HEAD CYLINDER AND PISTON 4 13 CLUTCH 4 21 KICK SHAFT AND SHIFT SHAFT 4 25 YPVS GOVERNOR 4 31 WATER PUMP 4 33 CDI MAGNETO 4 36 ENGINE REMOVAL 4 38 CRANKCASE AND CRANKSHAFT 4 42 TRANSMISSION SHIFT CAM AND SH...

Page 11: ...1 1 LOCATION OF IMPORTANT LABELS GENERAL INFORMATION LOCATION OF IMPORTANT LABELS Please read the following important labels carefully before operating this vehicle CANADA 1 ...

Page 12: ...1 2 LOCATION OF IMPORTANT LABELS EUROPE ...

Page 13: ...1 3 LOCATION OF IMPORTANT LABELS AUS NZ ZA ...

Page 14: ...ains high pressure nitrogen gas Mishandling can cause explosion Do not incinerate puncture or open Turn off the main switch after riding to avoid draining the battery Use unleaded gasoline only Measure tire pressure when tires are cold Adjust tire pressure Improper tire pressure can cause loss of control Loss of control can result in severe injury or death ...

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

Page 16: ...nstalled to the fuel tank breather hose In this installation make sure the arrow faces the fuel tank and also downward SET PIN This set pin 1 is used to remove and install the push rod of the engine Be sure to use the set pin If the set pin is not used the power valve constituent parts will result in damage NIPPLE WRENCH This nipple wrench 1 is used to tighten the spoke IMPORTANT INFORMATION PREPA...

Page 17: ...tweight 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 after one use Replace distorted cir clips When installing a circlip 1 make sure that the sharp edged corner 2 i...

Page 18: ...use Illustration Crankcase separating tool YU 01135 B 90890 01135 These tool is used to remove the crankshaft from either case Flywheel puller YM 01189 90890 01189 This tool is used to remove the fly wheel magneto Rotor holding tool YU 01235 90890 01235 This tool is used when loosening or tightening the flywheel magneto se curing nut Dial gauge and stand YU 03097 B 90890 01252 Stand YU 01256 These...

Page 19: ...1500 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 Spoke nipple wrench YM 01521 90890 01521 This tool is used to tighten the spoke Pocket tester YU 03112 C 90890 03112 Use this tool to inspect...

Page 20: ...ark tester YM 34487 Ignition checker 90890 06754 This instrument is necessary for checking the ignition system compo nents Digital tachometer YU 39951 B 90890 06760 This tool is needed for observing en gine rpm Yamaha bond No 1215 90890 85505 Three bond No 1215 This sealant Bond is used for crankcase mating surface etc Tool name Part number How to use Illustration ...

Page 21: ...r to activate the front brake REAR 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...

Page 22: ...ate the machine in the lower gears at moderate throttle open ings for five to eight minutes Stop and check the spark plug condi tion it will show a rich condition during break in 5 Allow the engine to cool Restart the engine and operate the ma chine as in the step above for five minutes Then very briefly shift to the higher gears and check full throttle response Stop and check the spark plug 6 Aft...

Page 23: ...lower bracket Rear For link 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 f...

Page 24: ...ANING AND STORAGE CLEANING Frequent cleaning of your machine will enhance its appearance maintain good overall performance and ex tend the life of many components 1 Before washing the machine block off the end of the exhaust pipe to prevent water from enter ing A plastic bag secured with a rubber band may be used for this purpose 2 If the engine is excessively greasy apply some degreaser to it wit...

Page 25: ...re stroke 66 4 72 mm 2 6 2 8 in Compression ratio 8 9 10 6 1 Starting system Kick starter Lubrication system Premix 30 1 YAMALUBE 2 R Oil type or grade 2 stroke Transmission oil Recommended brand YAMALUBE SAE10W 40 API service SG type or higher JASO standard MA Periodic oil change 0 75 L 0 66 Imp qt 0 79 US qt Total amount 0 80 L 0 70 Imp qt 0 85 US qt Coolant capacity including all routes 1 20 L ...

Page 26: ...4 3 in Tire Type With tube Size front 80 100 21 51M Size rear 110 90 19 62M Tire pressure front and rear 100 kPa 1 00 kgf cm2 15 psi Brake Front brake type Single disc brake Operation Right hand operation Rear brake type Single disc brake Operation Right foot operation Suspension Front suspension Telescopic fork Rear suspension Swingarm link type monocross suspension Shock absorber Front shock abs...

Page 27: ...6 367 mm 2 6123 2 6129 in Measuring point H 17 5 mm 0 69 in Piston clearance 0 045 0 050 mm 0 0018 0 0020 in 0 100 mm 0 0039 in Piston offset 1 50 mm 0 0591 in EX side Piston pin Piston pin outside diameter 17 995 18 000 mm 0 7085 0 7087 in 17 975 mm 0 7077 in Piston ring Sectional sketch Plain B 1 00 mm 0 04 in T 2 55 mm 0 10 in End gap installed 0 40 0 55 mm 0 0157 0 0217 in 0 95 mm 0 0374 in Si...

Page 28: ...0 067 in Quantity 7 Warp limit 0 20 mm 0 008 in Clutch spring free length 50 00 mm 1 97 in 48 00 mm 1 89 in Quantity 6 Clutch housing thrust clearance 0 17 0 23 mm 0 007 0 009 in Clutch housing radial clearance 0 03 0 05 mm 0 0012 0 0022 in Clutch release method Inner push cam push Transmission Main axle deflection limit 0 01 mm 0 0004 in Drive axle deflection limit 0 01 mm 0 0004 in Shifter Shift...

Page 29: ...t size V S ø3 8 mm 0 15 in Starter jet G S 85 Power jet P W J 50 Float arm height F H 5 5 7 5 mm 0 22 0 30 in Reed valve Thickness 0 420 mm 0 0165 in Valve stopper height 10 3 10 7 mm 0 41 0 42 in Valve bending limit 0 2 mm 0 01 in Cooling Radiator core size Width 107 8 mm 4 24 in Height 240 0 mm 9 45 in Thickness 32 0 mm 1 26 in Radiator cap opening pressure 95 0 125 0 kPa 0 95 1 25 kg cm2 13 8 1...

Page 30: ...n Spring free length 260 0 mm 10 24 in Fitting length 248 0 mm 9 76 in Preload length Min Max 1 5 18 mm 0 06 0 71 in Spring rate STD K 48 00 N mm 4 89 kg mm 274 08 lb in Optional spring Yes Enclosed gas pressure 1 000 kPa 10 0 kg cm2 142 2 psi Swingarm Swingarm free play limit End 1 0 mm 0 04 in Side clearance 0 2 0 9 mm 0 01 0 04 in Wheel Front wheel type Spoke wheel Rear wheel type Spoke wheel F...

Page 31: ...l height vertical height above footrest top 0 0 mm 0 00 in Clutch lever free play lever end 7 0 12 0 mm 0 28 0 47 in Throttle grip free play 3 0 5 0 mm 0 12 0 20 in Item Standard Limit Item Standard Limit Ignition system Ignition timing B T D C 0 18 mm 0 007 in Advancer type Electrical CDI Magneto model stator Manufacturer 5CU 20 YAMAHA Charging coil 1 resistance color 720 0 1 080 0 Ωat 20 C 68 F ...

Page 32: ...5 Nm 0 5 m kg 3 6 ft lb YPVS Impeller M8 1 14 Nm 1 4 m kg 10 ft lb Water pump housing cover M6 4 10 Nm 1 0 m kg 7 2 ft lb Coolant drain bolt M6 1 10 Nm 1 0 m kg 7 2 ft lb Copper washer Radiator M6 6 10 Nm 1 0 m kg 7 2 ft lb Radiator guard M6 2 10 Nm 1 0 m kg 7 2 ft lb Radiator hose clamp M6 8 2 Nm 0 2 m kg 1 4 ft lb Air filter element M6 1 2 Nm 0 2 m kg 1 4 ft lb Carburetor joint M6 5 10 Nm 1 0 m ...

Page 33: ... stopper M6 2 10 Nm 1 0 m kg 7 2 ft lb Clutch cover M6 6 10 Nm 1 0 m kg 7 2 ft lb Primary drive gear M10 1 55 Nm 5 5 m kg 40 ft lb Clutch boss M20 1 75 Nm 7 5 m kg 54 ft lb Lock washer Clutch spring M6 6 10 Nm 1 0 m kg 7 2 ft lb Clutch cable adjust bolt and locknut M6 1 4 Nm 0 4 m kg 2 9 ft lb Push lever axle M5 1 6 Nm 0 6 m kg 4 3 ft lb Drive sprocket M20 1 75 Nm 7 5 m kg 54 ft lb Lock washer Shi...

Page 34: ...nting nut M6 1 4 Nm 0 4 m kg 2 9 ft lb Clutch lever holder M6 2 5 Nm 0 5 m kg 3 6 ft lb Clutch lever position locknut M5 1 5 Nm 0 5 m kg 3 6 ft lb Engine stop switch screw M3 1 0 5 Nm 0 05 m kg 0 36 ft lb Front brake master cylinder and bracket M6 2 9 Nm 0 9 m kg 6 5 ft lb Front brake master cylinder cap M4 2 2 Nm 0 2 m kg 1 4 ft lb Brake lever mounting bolt M6 1 6 Nm 0 6 m kg 4 3 ft lb Brake leve...

Page 35: ...elay arm and connecting rod M14 1 80 Nm 8 0 m kg 58 ft lb Connecting rod and frame M14 1 80 Nm 8 0 m kg 58 ft lb Rear shock absorber and frame M10 1 56 Nm 5 6 m kg 40 ft lb Rear shock absorber and relay arm M10 1 53 Nm 5 3 m kg 38 ft lb Rear shock absorber adjust locknut M56 1 30 Nm 3 0 m kg 22 ft lb Rear frame and frame upper M8 1 32 Nm 3 2 m kg 23 ft lb Rear frame and frame lower M8 2 29 Nm 2 9 ...

Page 36: ...r M6 4 10 Nm 1 0 m kg 7 2 ft lb Rear fender front M6 2 7 Nm 0 7 m kg 5 1 ft lb Rear fender rear M6 2 12 Nm 1 2 m kg 8 7 ft lb Mud flap 2 1 Nm 0 1 m kg 0 7 ft lb Number plate M6 1 7 Nm 0 7 m kg 5 1 ft lb Item Thread size Q ty Tightening torque Remarks Item Thread size Q ty Tightening torque Remarks Stator M6 3 7 Nm 0 7 m kg 5 1 ft lb Rotor M12 1 56 Nm 5 6 m kg 40 ft lb Ignition coil M6 2 7 Nm 0 7 m...

Page 37: ...nts 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 We...

Page 38: ...t side of the throttle cable and en gine stop switch lead B Align the throttle cable locating tape with the cable guide C Pass the throttle cable clutch cable and engine stop switch lead above the radiator hose D Clamp the engine stop switch lead to the frame Tighten the clamp so that the engine stop switch lead is not pulled when the handlebar is turned to the right and left E Clamp the throttle ...

Page 39: ...tening nut H Pass the air vent hose overflow hose and crankcase breather hose between the frame and connecting rod I Locate the clamp ends in the ar rowed range J Pass the throttle cable behind the air vent hose K Pass the air vent hose overflow hose and crankcase breather hose so that they do not contact the rear shock absorber L Clamp the air vent hoses ...

Page 40: ...I magneto lead to the frame at its locating tape Clamp it at the rear of the radia tor fitting boss C Do not allow the neutral switch lead to slacken except over the radiator hose D Pass the neutral switch lead through the holder E Pass the radiator breather hose outside the engine bracket and inside the down tube Then pass the radiator breather hose inside the CDI magneto lead F Clamp the CDI mag...

Page 41: ...reather hose and neutral switch lead in front of the radia tor hose Then pass the radiator breather hose inside the CDI magneto lead and neutral switch lead I Pass the radiator breather hose and ignition coil lead between the frame and the radiator left J Locate the clamp ends in the ar rowed range K Bring the connector cover into contact with the coupler ...

Page 42: ...e right engine bracket B Pass the high tension cord to the right of the radiator hose so that the high tension cord does not contact the radiator hose C Pass the CDI unit lead between the frame and the radiator right and then above the radiator fit ting boss D Bring the connector cover into contact with the coupler E Pass the radiator breather hose behind the radiator hose F Insert the CDI unit ba...

Page 43: ...ion directs as shown and lightly touches the projec tion on the 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 master cylinder ...

Page 44: ... that its pipe portion directs as shown and lightly touches the projec tion on the master cylinder B Pass the engine stop switch lead in the middle of the clutch holder C Clamp the engine stop switch lead to the handlebar D Pass the brake hose in front of the number plate and through the cable guide E Pass the clutch cable through the cable guide on the number plate 0 in 0 mm 0 mm 0 in ...

Page 45: ...nspection is required by reference to the list below Item After break in Every race about 2 5 hours Every third about 7 5 hours Every fifth about 12 5 hours As re quired Remarks PISTON Inspect and clean Inspect crack Replace Inspect carbon deposits and eliminate them PISTON RING Inspect Check ring end gap Replace PISTON PIN SMALL END BEARING Inspect Replace CYLINDER HEAD Inspect carbon deposits an...

Page 46: ...hain slack 48 0 58 0 mm 1 89 2 28 in Replace COOLING SYSTEM Check coolant level and leakage Check radiator cap opera tion Replace coolant Every two years Inspect hoses OUTSIDE NUTS AND BOLTS Retighten Refer to STARTING AND BREAK IN section in the CHAPTER 1 AIR FILTER Clean and lubricate Use foam air filter oil or equiv alent oil Replace FRAME Clean and inspect FUEL TANK COCK Clean and inspect Item...

Page 47: ... 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 Retighten DRIVE CHAIN GUIDE AND ROLLERS Inspect SWINGARM Inspect lube and retighten Molybdenum disulfide grease RELAY ARM CONNECT ING ROD Inspect lube and retighten Molybdenum disulfide grease STEERING HEAD Inspect free play and re tighte...

Page 48: ...en sprocket bolt Inspect bearings Replace bearings Lubricate Lithium base grease THROTTLE CONTROL CA BLE Check routing and connec tion Lubricate Yamaha cable lube or SAE 10W 40 motor oil Item After break in Every race about 2 5 hours Every third about 7 5 hours Every fifth about 12 5 hours As re quired Remarks ...

Page 49: ...drive chain slack and alignment Check that the drive chain is lubricated properly P 3 13 14 Wheels Check for excessive wear and tire pressure Check for loose spokes and have no excessive play P 3 16 17 Steering Check that the handlebar can be turned smoothly and have no ex cessive play P 3 17 18 Front forks and rear shock absorber Check that they operate smoothly and there is no oil leakage P 3 14...

Page 50: ...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 51: ...st Clutch lever free play Handlebar side a Turn the adjuster 1 until the specified clutch lever free play is obtained If the clutch lever free play cannot be obtained on the handlebar side use the adjuster on the clutch cable side Clutch cable side a Slide the clutch cable cover b Loosen the locknut 1 c Turn the adjuster 2 until the specified clutch lever free play is obtained d Tighten the locknu...

Page 52: ...nt by squeezing 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 h...

Page 53: ... of turns To optimize the fuel flow at a smaller throttle opening each machine s pilot air screw has been individually set at the factory Before adjusting the pilot air screw turn it in fully and count the number of turns Record this number as the factory set number of turns out ADJUSTING THE ENGINE IDLING SPEED 1 Start the engine and thoroughly warm it up 2 Adjust Engine idling speed Adjustment s...

Page 54: ...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 55: ...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 56: ...d 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 F...

Page 57: ... specification 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 turni...

Page 58: ...E FRONT FORK REBOUND DAMPING FORCE 1 Adjust Rebound 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 adjuster may be damaged Always adjust each front fork to the same setting Uneven adjust ment can cause poor h...

Page 59: ...Never attempt to turn the adjuster beyond the maximum or minimum setting e Tighten the locknut 5 Install Rear frame upper Rear frame lower ADJUSTING THE REAR SHOCK ABSORBER REBOUND DAMPING FORCE 1 Adjust Rebound 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 Which align the punch mark a...

Page 60: ... tire while it is cold Loose bead stoppers allow the tire to slip off its position on the rim when the tire pressure is low A tilted tire valve 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 The following procedure applies to al...

Page 61: ...ring ring nut us ing the steering nut wrench Avoid over tightening g Check the M stem by turning it lock to lock If there is any binding remove the steering stem assem bly and inspect the steering bear ings h Install the washer 5 upper bracket 6 washer 7 steering stem nut 8 handlebar 9 han dlebar upper holders 10 and number plate 11 The handlebar upper holder should be installed with the punched m...

Page 62: ...3 18 CHASSIS ...

Page 63: ...dlebar contact 6 Drive chain 7 Throttle roller cable guide 8 Throttle roller sliding surface 9 Tube guide cable winding por tion 10 Throttle cable end 11 Clutch cable end A Use Yamaha cable lube or equivalent on these areas B Use SAE 10W 40 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 a...

Page 64: ...ug Crankcase cover left 2 Attach Dial gauge 1 Spark plug hole dial stand 2 3 Rotate the magneto rotor 1 until the piston reaches top dead cen ter TDC When this happens the needle on the dial gauge will stop and reverse directions even though the rotor is being turned in the same direction 4 Set the dial gauge to zero at TDC 5 From TDC rotate the rotor clock wise until the dial gauge indicates that...

Page 65: ...HE SEAT FUEL TANK 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 Fitting band 1 Remove on fuel tank side 4 Bolt fuel tank 2 5 Fuel tank 1 6 Left side cover 1 Refer to removal section 7 Right side cover 1 Refer to removal section 8 Number plate 1 Refer to removal section 6 Nm 0 6 m kg 4 3 ft lb 6 Nm 0 6 m kg 4 ...

Page 66: ...he air filter case REMOVING THE NUMBER PLATE 1 Remove Bolt number plate Number plate 1 The projection a is inserted into the band of the number plate Pull the band off the projection before removal Remove the clutch cable 2 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 ...

Page 67: ...on 1 Bolt silencer 2 2 Washer ø 26 mm 1 02 in 1 3 Washer ø 22 mm 0 87 in 1 4 Silencer 1 5 Collar L 15 5 mm 0 61 in 1 6 Collar L 13 5 mm 0 53 in 1 7 Grommet front 1 8 Grommet rear 1 9 Tension spring 2 10 Bolt exhaust pipe 2 11 Exhaust pipe 1 14 Nm 1 4 m kg 10 ft lb 25 Nm 2 5 m kg 18 ft lb 10 Nm 1 0 m kg 7 2 ft lb 12 Nm 1 2 m kg 8 7 ft lb 12 Nm 1 2 m kg 8 7 ft lb 12 Nm 1 2 m kg 8 7 ft lb ...

Page 68: ...ipe Fully apply Quick gasket Yamaha bond No 1215 or equivalent as shown 5 Install Bolt fiber 1 Silencer 2 Bolt silencer front 3 Bolt silencer rear 4 Side cover right Yamaha bond No 1215 90890 85505 Three bond No 1215 Bolt fiber 10 Nm 1 0 m kg 7 2 ft lb Bolt silencer front 12 Nm 1 2 m kg 8 7 ft lb Bolt silencer rear 12 Nm 1 2 m kg 8 7 ft lb Side cover right 7 Nm 0 7 m kg 5 1 ft lb ...

Page 69: ... FUEL TANK AND SIDE COVERS section 1 Radiator guard 2 2 Radiator hose clamp radiator hose 2 2 Only loosening 3 Radiator hose 1 1 4 Left radiator 1 5 Radiator hose 4 1 6 Right radiator 1 7 Radiator hose 2 2 8 Radiator breather hose 1 2 Nm 0 2 m kg 1 4 ft lb 2 Nm 0 2 m kg 1 4 ft lb 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb ...

Page 70: ...the ra diator Bent fin Repair replace INSTALLING THE RADIATOR 1 Install Radiator breather hose 1 Radiator hose 2 2 To right radiator 3 2 Install Right radiator 1 Washer 2 Bolt right radiator 3 Radiator hose 4 4 Refer to CABLE ROUTING DIA GRAM section in the CHAPTER 2 3 Install Left radiator 1 Washer 2 Bolt left radiator 3 Radiator hose 1 4 Refer to CABLE ROUTING DIA GRAM section in the CHAPTER 2 4...

Page 71: ... section 1 Solenoid valve lead 1 Disconnect the solenoid valve lead 2 Throttle position sensor lead 1 Disconnect the throttle position sensor lead 3 Clamp carburetor joint 2 Loosen the screw carburetor joint 4 Carburetor 1 5 Carburetor joint 1 6 Reed valve assembly 1 7 Stopper reed valve 2 8 Reed valve 2 9 Plate reed valve 1 10 Nm 1 0 m kg 7 2 ft lb 1 Nm 0 1 m kg 0 7 ft lb ...

Page 72: ... Throttle valve 1 Refer to removal section 3 Needle holder 1 4 Jet needle 1 5 Float chamber 1 6 Float pin 1 7 Float 1 8 Needle valve 1 9 Main jet 1 10 Pilot jet 1 11 Starter plunger 1 12 Throttle stop screw 1 13 Pilot air screw 1 Refer to removal section 14 Pilot jet 1 15 Starter plunger 1 4 Nm 0 4 m kg 2 9 ft lb ...

Page 73: ...for cleaning Blow out all passages and jets with compressed air Never use a wire CHECKING THE NEEDLE VALVE 1 Inspect Needle valve 1 Valve seat 2 Grooved wear a Replace Dust b Clean CHECKING THE THROTTLE VALVE 1 Check Free movement Stick Repair or replace Insert the throttle valve 2 into the carburetor body while pulling up the lever 1 and check for free move ment CHECKING THE JET NEEDLE 1 Inspect ...

Page 74: ...Install Carburetor joint 1 Bolt carburetor joint 2 ASSEMBLING THE CARBURETOR 1 Install Power jet 1 To carburetor 2 2 Install O ring 1 Solenoid valve 2 To carburetor Before installing the solenoid valve blow air on the solenoid valve and its installing location on the carburetor in order to re move any foreign particles such as chips etc Apply the engine oil on the sole noid valve thread 3 Install ...

Page 75: ...rd the car buretor 9 Install Jet needle 1 Collar 2 Spring 3 Needle holder 4 To throttle valve 5 Install the spring with its smaller dia a facing the collar 10 Install Throttle cable 1 Locknut 2 Mixing chamber top 3 Spring throttle valve 4 Ring 5 Throttle valve 6 While compressing the spring con nect the throttle cable Align the projection a on the ring with the groove b in the needle holder 7 11 I...

Page 76: ... and secure the clamp in alignment with the horizontal line b that passes the center of the carbure tor 4 Connect Throttle position sensor lead 1 Solenoid valve lead 2 Refer to CABLE ROUTING DIA GRAM section in the CHAPTER 2 5 Adjust Idle speed Refer to ADJUSTING THE EN GINE IDLING SPEED section in the CHAPTER 3 ...

Page 77: ... head side Carburetor Refer to CARBURETOR AND REED VALVE section 1 Spark plug 1 2 Engine bracket 2 3 Nut cylinder head 6 Loosen each nut 1 4 turn and remove them after all nuts are loosened 4 Cylinder head 1 5 Power valve housing 1 6 Push rod 1 Refer to removal section 7 Nut cylinder 4 8 Cylinder 1 34 Nm 3 4 m kg 24 ft lb 64 Nm 6 4 m kg 46 ft lb 20 Nm 2 0 m kg 14 ft lb 5 Nm 0 5 m kg 3 6 ft lb 25 N...

Page 78: ... section 4 Small end bearing 1 Refer to removal section 5 Piston ring 2 Refer to removal section 6 Power valve cover 1 7 Side holder 2 8 Thrust plate 1 9 Bolt 3 10 Valve holder 1 1 11 Valve shaft 1 12 Link lever 1 13 Pulley 2 14 Link rod 1 15 Power valve 2 2 16 Valve holder 2 1 17 Power valve 1 1 6 Nm 0 6 m kg 4 3 ft lb 4 Nm 0 4 m kg 2 9 ft lb 4 Nm 0 4 m kg 2 9 ft lb 4 Nm 0 4 m kg 2 9 ft lb 4 Nm 0...

Page 79: ...more than necessary CHECKING THE CYLINDER HEAD 1 Eliminate Carbon deposits Use a rounded scraper 1 Take care to avoid damaging the spark plug threads Do not use a sharp instrument Avoid scratching the aluminum 2 Inspect Cylinder head water jacket Crust of minerals Rust Re place 3 Measure Cylinder head warpage Out of specification Resurface Warpage measurement and resur facing steps a Attach a stra...

Page 80: ...en the piston pin 1 is in place in the piston 2 There should be no noticeable for the play Free play exists Replace piston pin and or piston 4 Install Small end bearing Piston pin Into the small end of connecting rod 5 Check Free play There should be no noticeable free play Free play exists Inspect the connecting rod for wear Replace the pin and or connecting rod as required CHECKING THE PISTON RI...

Page 81: ...y 4 Valve shaft 5 Link rod 6 Washer 7 Wear Damage Replace Spring 1 2 8 Broken Replace CHECKING THE POWER VALVE HOLE ON CYLINDER 1 Remove Carbon deposits From power valve hole surface a Do not use a sharp instrument Avoid scratching the aluminum Side clearance Standard Limit 0 030 0 065 mm 0 0012 0 0026 in 0 100 mm 0 0039 in PISTON CLEARANCE CYLIN DER BORE PISTON DIAME TER Piston clearance Standard...

Page 82: ...tall the valve shaft with its cut b aligning with the thrust plate 7 and then rotate the valve shaft so that its cut faces upward 5 Install Valve holder 1 1 Bolt link lever 2 Bolt pulley 3 First tighten the bolt link lever and then tighten the bolts pulleys 6 Check Power valve 1 smooth movement Unsmooth movement Repair or replace 7 Install O ring 1 Side holder 2 Screw side holder 3 YPVS breather h...

Page 83: ...iston pin clip from falling into the crankcase cavi ty Apply the engine oil on the piston pin Do not allow the clip open ends to meet the piston pin slot b INSTALLING THE CYLINDER HEAD AND CYLINDER 1 Apply Engine oil To piston 1 piston ring 2 and cylinder surface 2 Install Cylinder 1 Make sure the piston rings are properly positioned Install the cyl inder with one hand while com pressing the pisto...

Page 84: ...er washer 2 Nut cylinder head 3 Tighten the nuts cylinder head in stage using a crisscross pattern 8 Install Engine bracket 1 Bolt engine bracket 2 Engine mounting bolt upper 3 9 Install Spark plug 1 Spark plug cap 2 Bolt power valve hous ing 5 Nm 0 5 m kg 3 6 ft lb Nut cylinder head 25 Nm 2 5 m kg 18 ft lb Bolt engine bracket 34 Nm 3 4 m kg 24 ft lb Engine mounting bolt upper 64 Nm 6 4 m kg 46 ft...

Page 85: ...ION OIL section in the CHAPTER 3 Bolt brake pedal Shift the brake pedal downward Rotor and stator Refer to CDI MAGNETO section Clutch cable Disconnect at engine side 1 Clutch cover 1 2 Bolt clutch spring 6 3 Clutch spring 6 4 Pressure plate 1 5 Friction plate 8 6 Clutch plate 7 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb ...

Page 86: ... 6 Nut clutch boss 1 Refer to removal section 7 Lock washer 1 Refer to removal section 8 Clutch boss 1 Refer to removal section 9 Thrust washer D ø44mm 1 73 in 1 10 Primary driven gear 1 11 Bearing 1 12 Thrust washer D ø42mm 1 65 in 1 13 Bolt push lever shaft 1 14 Push lever shaft 1 75 Nm 7 5 m kg 54 ft lb 6 Nm 0 6 m kg 4 3 ft lb ...

Page 87: ...TES 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 Wear damage bend Replace INSTALLING THE PUSH LEVER SHAFT 1 Install Push lever shaft 1 Copper washer 2 Bolt push l...

Page 88: ... rod 1 4 Apply the lithium soap base grease on the bearing and washer 7 Install Push rod 2 1 Push rod 1 2 Apply the transmission oil on the ends of the push rod 2 Install the push rod 2 with its small er end a toward you 8 Install Pressure plate 1 9 Install Clutch spring 1 Bolt clutch spring 2 Tighten the bolts in stage using a crisscross pattern 10 Install O ring 1 To clutch cover 11 Install Clut...

Page 89: ...pedal Shift the brake pedal downward Radiator hose 4 Disconnect at water pump side Bolt push rod Refer to CYLINDER HEAD CYLINDER AND PISTON section 1 Kickstarter lever 1 2 Crankcase cover right 1 3 Bolt Primary drive gear 1 Only loosening Refer to removal section 4 Primary driven gear 1 Refer to CLUTCH section 5 Primary drive gear 1 6 Thrust plate 1 10 Nm 1 0 m kg 7 2 ft lb 30 Nm 3 0 m kg 22 ft lb...

Page 90: ...k shaft assembly 1 Refer to removal section 3 Shift pedal 1 4 Shift shaft 1 5 Roller 1 6 Shift guide 1 Refer to removal section 7 Shift lever assembly 1 Refer to removal section 8 Stopper lever 1 9 Holder 1 10 Tension spring 1 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb 12 Nm 1 2 m kg 8 7 ft lb ...

Page 91: ... an impact to it when removing the bolt CHECKING THE KICK SHAFT AND RATCHET WHEEL 1 Check Ratchet wheel 1 smooth move ment Unsmooth movement Replace Kick shaft 2 Wear damage Replace Spring 3 Broken Replace CHECKING 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...

Page 92: ...e 2 The shift lever assembly is installed at the same time as the shift guide Apply the transmission oil on the bolt segment shaft 4 Install Bolt shift guide 1 INSTALLING THE SHIFT SHAFT 1 Install Roller 1 Washer 2 Shift shaft 3 Apply the transmission oil on the roll er and shift shaft INSTALLING THE KICK SHAFT ASSEMBLY 1 Install Kick gear 1 Washer 2 Circlip 3 Ratchet wheel 4 Spring 5 Washer 6 Cir...

Page 93: ...ard you INSTALLING THE PRIMARY DRIVE GEAR 1 Install Thrust plate 1 Primary drive gear 2 Governor drive gear 3 Washer 4 Bolt primary drive gear 5 Install the plain washer with its chamfered side a toward you Temporarily tighten the bolt at this point 2 Install Primary driven gear Refer to CLUTCH section 3 Tighten Bolt primary drive gear 1 Place an aluminum plate a between the teeth of the primary d...

Page 94: ... shift pedal 2 Install the shift pedal so that the top of the shift pedal outer diameter a is highest without exceeding the line b connecting the center of the shift shaft and bottom of the screw crank case cover left 3 Bolt shift pedal 12 Nm 1 2 m kg 8 7 ft lb ...

Page 95: ...rks Crankcase cover right Refer to KICK SHAFT AND SHIFT SHAFT section 1 Governor assembly 1 2 Dowel pin 1 Refer to removal section 3 Retainer 1 4 Ball 4 5 Retainer weight 1 6 Washer 4 7 Thrust bearing 2 8 Collar 1 9 Plate 1 10 Compression spring 1 11 Governor gear 1 12 Governor shaft 1 ...

Page 96: ...ompression spring 2 Plate 3 Washer 4 Thrust bearing 5 Collar 6 Retainer weight 7 To governor shaft 8 Apply the lithium soap base grease on the thrust bearing 2 Install Ball 1 Retainer 2 To governor shaft 3 Apply the transmission oil on the re tainer and ball 3 Install Dowel pin 1 While compressing the spring in stall the dowel pin Make sure the dowel pin fits into the groove a in the retainer 4 In...

Page 97: ...HAFT AND SHIFT SHAFT section 1 Water pump housing cover 1 2 Impeller 1 Refer to removal section 3 Washer 1 Refer to removal section 4 Impeller shaft 1 Refer to removal section 5 Bearing 1 Refer to removal section 6 Oil seal 2 Refer to removal section 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb 14 Nm 1 4 m kg 10 ft lb ...

Page 98: ...h 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 Install the bearing by pressing its out er race parallel INSTALLING THE IMPELLER SHAFT 1 Install ...

Page 99: ...nstall Water pump housing cover 1 Bolt water pump housing cover 2 Copper washer coolant drain bolt 3 Coolant drain bolt 4 Bolt water pump hous ing cover 10 Nm 1 0 m kg 7 2 ft lb Coolant drain bolt 10 Nm 1 0 m kg 7 2 ft lb ...

Page 100: ...o SEAT FUEL TANK AND SIDE COVERS section Bolt Radiator Refer to RADIATOR section Disconnect the CDI magneto lead 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 7 Nm 0 7 m kg 5 1 ft lb 5 Nm 0 5 m kg 3 6 ft lb 56 Nm 5 6 m kg 40 ft lb ...

Page 101: ...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 Adjust Ignition timing Refer to CHECKING THE IGNI TION TIMING section in the CHAPTER 3 5 Tighten Screw stator 1 6 Check Ignition timing Re check the ignition timing 7 Connect CDI m...

Page 102: ...ETOR AND REED VALVE section Exhaust pipe and silencer Refer to EXHAUST PIPE AND SILENCER section Exhaust pipe stay rear Refer to EXHAUST PIPE AND SILENCER section Clutch cable Disconnect at engine side Radiator Refer to RADIATOR section Spark plug Disconnect the CDI magneto lead 1 Neutral switch 1 Disconnect the neutral switch lead 2 Drive chain sprocket cover 1 34 Nm 3 4 m kg 24 ft lb 64 Nm 6 4 m...

Page 103: ...t brake pedal 1 8 Brake pedal 1 9 Engine bracket 2 10 Engine mounting bolt 3 11 Pivot shaft 1 Remove completely 12 Engine 1 Refer to removal section Order Part name Q ty Remarks 34 Nm 3 4 m kg 24 ft lb 64 Nm 6 4 m kg 46 ft lb 26 Nm 2 6 m kg 19 ft lb 64 Nm 6 4 m kg 46 ft lb 75 Nm 7 5 m kg 54 ft lb 4 Nm 0 4 m kg 2 9 ft lb 85 Nm 8 5 m kg 61 ft lb 5 Nm 0 5 m kg 3 6 ft lb ...

Page 104: ... the engine from right side Pivot shaft 2 Nut pivot shaft 3 Engine mounting bolt lower 4 Nut engine mounting bolt lower 5 Engine mounting bolt front 6 Nut engine mounting bolt front 7 Engine bracket 8 Bolt engine bracket 9 Nut engine bracket 10 Engine mounting bolt upper 11 Nut engine mounting bolt up per 12 Apply the molybdenum disulfide grease on the pivot shaft INSTALLING THE BRAKE PEDAL 1 Inst...

Page 105: ... lock washer tab to lock the nut 4 Install Drive chain sprocket guide 1 Drive chain sprocket cover 2 Screw drive chain sprocket cov er 3 5 Connect Neutral switch lead Refer to CABLE ROUTING DIA GRAM section in the CHAPTER 2 Nut drive sprocket 75 Nm 7 5 m kg 54 ft lb Screw drive chain sprocket cover 5 Nm 0 5 m kg 3 6 ft lb ...

Page 106: ...Refer to KICK SHAFT AND SHIFT SHAFT section Stopper lever Refer to KICK SHAFT AND SHIFT SHAFT section Rotor and stator Refer to CDI MAGNETO section 1 Segment 1 Refer to removal section 2 Holder 2 3 Bolt Neutral switch lead holder 1 4 Bolt L 50 mm 1 97 in 7 5 Bolt L 60 mm 2 36 in 1 6 Bolt L 70 mm 2 76 in 3 7 Holder 2 8 Crankcase right 1 Refer to removal section 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m ...

Page 107: ...removal section 10 Crankshaft 1 Refer to removal section 11 Oil seal 2 12 Bearing 2 Refer to removal section Order Part name Q ty Remarks 10 Nm 1 0 m kg 7 2 ft lb 10 Nm 1 0 m kg 7 2 ft lb 30 Nm 3 0 m kg 22 ft lb 14 Nm 1 4 m kg 10 ft lb 10 Nm 1 0 m kg 7 2 ft lb ...

Page 108: ... the cases do not separate check for a remaining case bolt or fitting Do not force REMOVING THE CRANKSHAFT 1 Remove Crankshaft 1 Use the crankcase separating tool 2 Make appropriate bolts 3 as shown available by yourself and attach the tool with them 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 i...

Page 109: ...for USA and CDN 2 Check Shifter operation Transmission operation Unsmooth operation Repair 3 Install O ring 1 To right crankcase 2 4 Apply Sealant On the right crankcase 1 Clean the contacting surface of left and right crankcase before applying the sealant 5 Install Dowel pin 1 Right crankcase 2 To right crankcase 3 Fit the right crankcase onto the left crankcase Tap lightly on the case with soft ...

Page 110: ... with the dowel pin b Turn the segment clockwise until it stops and tighten the bolt If the segment gets an impact the stopper lever may be damaged Take care not to give an impact to it when tightening the bolt 9 Remove Sealant Forced out on the cylinder mating surface 10 Apply Engine oil To the crank pin bearing oil de livery hole and connecting rod big end washer 11 Check Crankshaft and transmis...

Page 111: ...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 112: ... SHIFT CAM AND SEGMENT 1 Inspect Shift fork 1 Wear damage scratches 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 21T 1 3rd pinion gear 18T 2 C...

Page 113: ...eal lip Install the spacer with its chamfered side a facing the crankcase 5 Install Shift fork 1 L 1 Shift fork 2 C10 2 Shift 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 C10 with the 3rd pinion gear 6 on the ...

Page 114: ...dertake inspection adjustment disassembly or reassembly only by reference to this manual It may lead to servicing trouble and mechanical damage FRONT WHEEL AND REAR WHEEL REMOVING THE FRONT WHEEL 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 Fron...

Page 115: ...chine 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 5 ...

Page 116: ...ake disc deflection 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 specification 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 Us...

Page 117: ...eal 5 Apply 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 mad...

Page 118: ...xle 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 sla...

Page 119: ...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 120: ...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 121: ...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 122: ...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 123: ...tion when expelling piston from cylinder Never attempt to pry out piston Caliper piston removal 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 bra...

Page 124: ... caliper piston dust seals whenever a caliper is disassembled INSTALLING THE BRAKE CALIPER PISTON 1 Clean Brake caliper Brake caliper piston seal Brake caliper piston dust seal Brake caliper piston 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...

Page 125: ...r cup sec ondary 2 To brake master cylinder piston 3 Apply the brake fluid on the brake master cylinder cup After installing cylinder cup should be installed as shown di rection Wrong installation cause improper brake performance 3 Install Spring 1 To brake master cylinder piston 2 Install the spring at the smaller diam eter side 4 Install Brake master cylinder kit 1 Washer front brake 2 Push rod ...

Page 126: ...ction b on the brake master cylinder 2 Install Brake master cylinder 1 Bolt brake master cylinder 2 3 Install Spring 1 Brake pedal 2 O ring 3 Bolt brake pedal 4 Clip 5 Apply the lithium soap base grease on the bolt O ring and brake pedal bracket 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...

Page 127: ...brake hose holders make sure the brake hose does not contact the spring rear shock absorber If it does correct its twist FILLING THE BRAKE FLUID 1 Fill Brake fluid Until the fluid level reaches LOWER level line a Use only the designated quality brake fluid otherwise the rubber seals may deteriorate causing leakage and poor brake performance Refill with the same type of brake fluid mixing fluids ma...

Page 128: ...nt brake Diaphragm Brake master cylinder cap 1 Screw brake master cylinder cap 2 After installation while pulling the brake lever in or pushing down on the brake pedal check whether there is any brake fluid leaking where the union bolts are installed respectively at the brake master cylinder and brake caliper A Front B Rear 5 Install rear brake only Protector 1 Bolt protector 2 Screw bolt brake ma...

Page 129: ...r to FRONT WHEEL AND REAR WHEEL section Front brake caliper 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 ...

Page 130: ...r to removal section 5 Inner tube 1 Refer to removal section 6 Outer tube 1 7 Piston metal 1 8 Protector guide 1 9 Slide metal 1 10 Oil seal washer 1 11 Oil seal 1 12 Base valve 1 Drain the fork oil Refer to removal section 13 Damper assembly 1 Drain the fork oil Refer to removal section 1 Nm 0 1 m kg 0 7 ft lb 29 Nm 2 9 m kg 21 ft lb 55 Nm 5 5 m kg 40 ft lb 29 Nm 2 9 m kg 21 ft lb 30 Nm 3 0 m kg ...

Page 131: ...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 132: ...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 materials ...

Page 133: ...ile 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 The overflow measures about 8 cm3 0 28 Imp oz 0 27 US oz 14 Check Damper assembly smooth move ment Tightness binding rough spots Repeat the steps 2 to ...

Page 134: ...ame ter 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 o...

Page 135: ... 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 wr...

Page 136: ...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 137: ...hrottle cable cap 1 Turn over the cap cover 6 Throttle cable 1 Disconnect at the throttle side 7 Throttle 1 Loosen the bolts 8 Cap cover 1 9 Collar 1 10 Left grip 1 Refer to removal section 11 Handlebar upper holder 2 12 Handlebar 1 13 Handlebar lower holder 2 0 5 Nm 0 05 m kg 0 36 ft lb 0 5 Nm 0 05 m kg 0 36 ft lb 9 Nm 0 9 m kg 6 5 ft lb 28 Nm 2 8 m kg 20 ft lb 4 Nm 0 4 m kg 2 9 ft lb 4 Nm 0 4 m ...

Page 138: ...5 25 HANDLEBAR DISASSEMBLING THE THROTTLE Order Part name Q ty Remarks 1 Grip cap lower 1 2 Grip cap upper 1 3 Grip assembly 1 4 Grip right 1 Refer to removal section 5 Tube guide 1 ...

Page 139: ...p lower 2 Bolt grip cap 3 Temporarily tighten the bolts grip cap INSTALLING THE HANDLEBAR 1 Install Handlebar lower holder 1 Washer 2 Nut handlebar lower holder 3 Install the handlebar lower holder with its side having the greater dis tance a from the mounting bolt center facing forward Apply the lithium soap base grease on the thread of the handlebar low er holders Installing the handlebar lower ...

Page 140: ...ing surface and ca ble guide Install the roller so that the UP PER mark a faces upward Pass the throttle cable in the groove b in the roller 8 Install Throttle cable cap 1 Screw throttle cable cap 2 9 Adjust Throttle grip free play Refer to ADJUSTING THE THROTTLE GRIP FREE PLAY section in the CHAPTER 3 10 Install Cap cover 1 11 Install Brake master cylinder 1 Brake master cylinder bracket 2 Bolt b...

Page 141: ...dimensions shown Pass the engine stop switch lead in the middle of the clutch lever hold er 14 Install Clutch cable 1 Apply the lithium soap base grease on the clutch cable end 15 Adjust Clutch lever free play Refer to ADJUSTING THE CLUTCH LEVER FREE PLAY section in the CHAPTER 3 Engine stop switch 0 5 Nm 0 05 m kg 0 36 ft lb Bolt clutch lever holder 5 Nm 0 5 m kg 3 6 ft lb 0 mm 0 in 0 mm 0 in ...

Page 142: ... 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 1 Front fender 1 2 Steering stem nut 1 3 Front fork 2 Refer to FRONT FORK section 4 Upper bracket 1 5 Steering ring nut 1 Refer to removal section 6 Lower bracket 1 7 Bearing race cover 1 8 Upper bearing 1 9 Lower bearing 1 Refer to removal section 1...

Page 143: ...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 144: ...nt 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 0 mm 0 in Pinch bolt upper brack ...

Page 145: ...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 146: ...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 147: ...nspect Oil 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 r...

Page 148: ...t relay arm 4 To swingarm Apply the molybdenum 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 rou...

Page 149: ...r 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 connecting rod 80 Nm 8 0 m kg 58 ft lb 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 sup...

Page 150: ...AUST 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 Lower spring guide 1 9 Upper spring guide 1 10 Spring rear shock absorber 1 11 Bearing 2 Refer to removal section 56 Nm 5 ...

Page 151: ...n disposal NOTES ON DISPOSAL YAMAHA DEALERS ONLY Before disposing the rear shock ab 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 ...

Page 152: ...eal 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 inward 3 Install Rear shock absorber 4 Install Bolt rear shock absorber frame 1 Washer 2 Nut rear shock absorber frame 3 Apply the molybdenum disulfide grease on the bol...

Page 153: ...5 40 REAR SHOCK ABSORBER 7 Tighten Bolt air filter joint 1 ...

Page 154: ...is manual It may lead to servicing trouble and mechanical damage ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS 1 CDI unit 2 Engine stop switch 3 Ignition coil 4 Throttle position sensor 5 Solenoid valve 6 Neutral switch 7 CDI magneto 8 Spark plug WIRING DIAGRAM 1 CDI unit 2 Engine stop switch 3 Ignition coil 4 Throttle position sensor 5 Solenoid valve 6 Neutral switch 7 CDI magnet...

Page 155: ...lowing special tools in this inspection Spark gap test Spark Clean or replace spark plug No spark Check entire ignition system for connection 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 spark plug cap No good Replace OK Check CDI magneto pickup coil and charging coil No good Replace OK Check n...

Page 156: ...ap by turn ing it counterclockwise and inspect Install the spark plug cap by turning it clockwise until it is tight CHECKING THE SPARK PLUG CAP 1 Inspect Spark plug cap Loose connection Tighten Deteriorated damaged Re place Spark plug cap resistance Out of specification Replace CHECKING THE CDI MAGNETO 1 Inspect Pickup coil resistance Out of specification Replace Minimum spark gap 6 0 mm 0 24 in T...

Page 157: ...tion 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 Black Red lead 1 Tester lead Black lead 2 Charging coil 1 resis tance Tester se lector posi tion 720 0 1 080 0 Ω at 20 C 68 F Ω 100 Tester lead Green Blue lead 1 Tester lead Green White lead 2 Charging coil 2 resis tance Tester se lecto...

Page 158: ...wing parts before inspection 1 Seat 2 Fuel tank Use 12V battery in this inspection Use the following special tools in this inspection Check each couplers and wire connection No good Repair or replace OK Check solenoid valve Check solenoid valve op eration Solenoid valve coil No good Replace OK Check CDI magneto Source coil No good Replace OK Replace CDI unit Pocket tester YU 03112 C 90890 03112 ...

Page 159: ...lenoid valve coupler 2 Connect 12V battery to the sole noid valve coupler 3 Inspect Solenoid valve 1 No click when connecting the bat tery Replace CHECKING THE SOLENOID VALVE COIL 1 Inspect Solenoid valve coil resistance Out of specification Replace Tester lead Red lead 1 Tester lead Red lead 2 Tester lead Red lead 1 Tester lead Red lead 2 Solenoid resistance Tester se lector posi tion 22 8 27 8 Ω...

Page 160: ... the following parts before inspection 1 Seat 2 Fuel tank 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 Source coil No good Replace OK Check CDI unit Throttle position sensor input voltage No good Replace Pocket tester YU 03...

Page 161: ...nsor 2 Align the slot a in the throttle posi tion sensor with the projection b on the carburetor while the lever 3 is held down Temporarily tighten the screw throttle position sensor 5 Install Mixing chamber top Carburetor Refer to CARBURETOR AND REED VALVE section in the CHAPTER 4 6 Adjust Idle speed for throttle position sensor adjustment Adjustment steps a Set the digital tachometer to the high...

Page 162: ... the screws throttle position sensor using the T20 bit tamper re sistant fastener type by aligning the marks a that were put before re moval 14 Install Carburetor Refer to CARBURETOR AND REED VALVE section in the CHAPTER 4 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...

Page 163: ...air i e the concentration of oxygen in it Higher temperature expands the air with its resultant reduced density Higher humidity reduces the amount of oxygen in the air by so much of the water vapor in the same air Lower atmospheric pressure at a high altitude reduces the density of the air TEST RUN After warming up the engine equipped with the standard type car buretor s and spark plug s run two o...

Page 164: ...ip by one groove and move down the needle to lean out the mixture 2 Too lean at intermediate speeds The engine breathes hard and will not pick up speed quickly Step up the jet needle clip by one groove and move up the needle to enrich the mixture ADJUSTING THE JET NEEDLE On the carburetors used in the YZ250 the main nozzle is press fit ted so it can not be replaced There fore carburetor setting re...

Page 165: ...eter taper starting posi tion and clip position Example A Lean larger diameter B Rich smaller diameter 1 1 8 throttle 2 1 4 throttle 3 1 2 throttle 4 1 1 throttle a Main nozzle CARBURETOR SETTING PARTS N3EW 3 N3EW 4 N3EJ 3 N8RW 3 Main jet 1 Size Part number 14943 Rich 190 4MX 45 188 4MX 95 185 4MX 44 182 4MX 94 STD 180 4MX 43 STD 178 4MX 93 175 4MX 42 172 4MX 92 170 4MX 41 168 4MX 91 165 4MX 40 Le...

Page 166: ...is 1 add 1 to the value chosen in the chart General condition Sandy condition Under 10 C 50 F 15 25 C 59 77 F Over 25 C 77 F Under 10 C 50 F 15 25 C 59 77 F Over 25 C 77 F Winter Spring Au tumn Summer Winter Spring Au tumn Summer Main jet A 178 178 178 182 180 178 B 180 178 178 182 180 178 Jet needle A N3CW 3 N3EW 2 N3EJ 2 N3CW 3 N3CW 3 N3CW 3 B N3EW 3 N3CW 3 N3EW 2 N3CW 4 N3EW 3 N3EW 3 Pilot jet ...

Page 167: ...osition of jet needle groove to which the clip is fitted The position is numbered from the top 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 White smoke Poor acceleration Raise jet needle clip position 1 groove up 0 1 4 throttle Hard breathing Speed down Use jet ...

Page 168: ...e course and some settings may be sacrificed Thus the settings should be matched to the portion of the course that has the greatest ef fect on the race result In such a case run through the entire course while making notes of lap times to find the best balance then deter mine the secondary reduction ratio If a course has a long straight por tion where a machine can run at maximum speed the machine...

Page 169: ...ear suspension take care so that the machine front and rear are balanced in position etc when setting the front fork 1 Use of soft spring Change the rebound damping Turn out one or two clicks Change the compression damp ing Turn in one or two clicks Generally a soft spring gives a soft riding feeling Rebound damping tends to become stronger and the front fork may sink deeply over a se ries of gaps...

Page 170: ... the soft spring for more re bound damping to compensate for its greater spring load Run with the rebound damping adjust er one or two clicks on the stiffer side and readjust it to suit your preference Adjusting the rebound damping will be followed more or less by a change in the compression damping For cor rection turn the low compression damping adjuster on the softer side When using a rear shoc...

Page 171: ...RING PRE LOAD in the CHAPTER 3 SPRING PART NUMBER 22212 Maximum Minimum 5UN 00 5UN 10 5UN 20 5UN 30 5UN 40 5UN 50 5UN 60 5UN 70 5UN A0 5UN B0 5UN C0 5UN D0 5UN E0 5UN F0 5UN G0 Position in which the spring is turned in 18 mm 0 71 in from its free length Position in which the spring is turned in 1 5 mm 0 06 in from its free length ...

Page 172: ...ntire 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 o...

Page 173: ...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...

Page 174: ...PRINTED IN JAPAN E PRINTED ON RECYCLED PAPER ...

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Yamaha 2011 YZ250, Owner'S Manual

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