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Manual Yamaha WR450F (2008)

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  • Yamaha WR450F (2008) - page 1

    5TJ-28199-45 WR450F OWNER’S SERVICE MANUAL MANUEL D’ATELIER DU PROPRIETAIRE FAHRER- UND WARTUNGSHANDBUCH MANUAL DE SERVICIO DEL PROPIETARIO PRINTED IN JAPAN 2007.10-1.6 × 1 CR (E,F,G,S) WR450F PRINTED ON RECYCLED PAPER Y AMAHA MO T OR CO . , L TD . 2500 SHINGAI IW A T A SHIZUOKA JAP AN 2008 2008 ...

  • Yamaha WR450F (2008) - page 2

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  • Yamaha WR450F (2008) - page 3

    WR450F 5TJ-28199-45-E0 2008 OW NER’S SERVICE MANUAL ...

  • Yamaha WR450F (2008) - page 4

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  • Yamaha WR450F (2008) - page 5

    WR450F OWNER'S SERVICE MANUAL ©2007 by Yamaha Motor Co., Ltd. 1st Edition, October 2007 All rights reserved. Any reprin ting or unauthorized use wi thout the written permission of Yamaha Motor Co., Ltd. is expressly prohib ited. Printed in Japan ...

  • Yamaha WR450F (2008) - page 6

    FOREWORD INTRODUCTION Congratul ations on your pu rchase of a Yamaha WR series. This model is the culmination of Yamaha' s vast ex- perience in the production of paceset- ting racing machines. It represents the highest grade of craftsmanship and reliability that have made Yama- ha a leader. This manual explain s operation, in- spection, basic ...

  • Yamaha WR450F (2008) - page 7

    TO THE NEW OWNER This manual will provide you with a good basic understanding of fea- tures, operation, and basic mainte- nance and inspection items of this machine. Please read this manual carefully and comple tely before oper- ating your new machine. If you have any questions regarding the ope ra- tion or maintenan ce of your machine, please cons ...

  • Yamaha WR450F (2008) - page 8

    HOW TO READ DESCRIPTIONS To help identify parts and clarify pro- cedure steps, there are exploded dia - grams at the start of each removal and disassembly section. 1. An easy-to-see exploded diagram "1" is provided for removal and disassembly jobs. 2. Numbers "2" are given in the or- der of the jobs in the exploded di- agram. A ...

  • Yamaha WR450F (2008) - page 9

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

  • Yamaha WR450F (2008) - page 10

    CONTENTS CHAPTER 1 GENERAL INFOR- MATION DESCRIPTION ................. 1-1 MACHINE IDENTIFICATION ............. 1-2 INCLUDED PARTS .......... 1-2 IMPORTANT INFORMATION................. 1-2 CHECKING OF CONNEC- TION ................................. 1-3 SPECIAL TOOLS ............. 1-4 CONTROL FUNCTIONS .. 1-8 MULTI-FUNCTION DISPLAY .................. ...

  • Yamaha WR450F (2008) - page 11

    1-1 DESCRIPTION GENERAL INFORMATION DESCRIPTION • The machine you have purchased may differ slightly from those shown in the following. • Designs and specifications are subject to chang e without notice. 1. Clutch lever 2. Hot starter lever 3. Engine stop switch 4. Multi-function displ ay 5. Main switch 6. Start switch 7. Front brake lever 8. T ...

  • Yamaha WR450F (2008) - page 12

    1-2 MACHINE IDENTIFICATION MACHINE IDENTIFICATION There are two signifi cant reasons for knowing the serial number of your machine: 1. When ordering parts, you can give the number to your Yamaha dealer for positive identification of the model you own. 2. If your machine is stolen, the au- thorities will need the number to search for and identify yo ...

  • Yamaha WR450F (2008) - page 13

    1-3 CHECKING OF CONNECTION ALL REPLACEMENT PARTS 1. We recommend to use Yamaha genuine parts for all replace- ments. Use oil and/or grease rec- ommended by Yamaha for assembly and adj ustment. GASKETS, OIL SEALS AND O- RINGS 1. All gaskets, oil seals, and O-rings should be replaced when an en- gine is overhauled. Al l gasket sur- faces, oil seal li ...

  • Yamaha WR450F (2008) - page 14

    1-4 SPECIAL TOOLS SPECIAL TOOLS The proper spe cial tools are necessary for complet e and accura te tune-up and asse mbly. Using the correct sp ecial tool will help prevent damage caused by the use of improper too ls or improvised techniques . The shape an d part number used fo r the special tool differ by coun try, so two types are provided. Refer ...

  • Yamaha WR450F (2008) - page 15

    1-5 SPECIAL TOOLS Damper rod holder YM-01494, 90890-01494 Use this tool to remove and install the damper rod. Fork seal driver YM-A0948, 90890-01502 This tool is used when install th e fork oil seal. Sheave holder YS-1880-A, 90890-01701 This tool is used for when loosening or tightening the flywheel magneto securing nut. Pocket tester YU-3112-C, 90 ...

  • Yamaha WR450F (2008) - page 16

    1-6 SPECIAL TOOLS Clutch holding tool YM-91042, 90890-04086 This tool is used to hold the clutch when removing or installing th e clutch boss securing nut. Valve guide remover Intake 4.5 mm (0.18 in) Exhaust 5.0 mm (0.20 in) YM-4116, 90890-04116 YM-4097, 90890-04097 This tool is needed to remove and install the valve gui de. Valve guide installer I ...

  • Yamaha WR450F (2008) - page 17

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  • Yamaha WR450F (2008) - page 18

    1-8 CONTROL FUNCTIONS CONTROL FUNCTIONS MAIN SWITCH Functions of the respective switch po- sitions are as follows: ON: The engine can be started only at this position. OFF: All electrical circuits are switched off. Main switch indicator light The main switch "1" is equipped with an indicator light "2" to avoid forget- ting to tu ...

  • Yamaha WR450F (2008) - page 19

    1-9 MULTI-FUNCTION DISPLAY COLD STARTER KNOB When cold, the engine requires a richer air-fuel mixture for starting. A separate starter circuit, which i s con- trolled by the cold starter knob "1", supplies this mixture. Pull the cold starter knob out to open the circuit for starting. When the engine has warmed up, push it in to close the ...

  • Yamaha WR450F (2008) - page 20

    1-10 MULTI-FUNCTION DISPLAY To reset the digits, se lect the tripme- ter involved and push the "RST" but- ton for 2 seconds or more. CHANGEOVER TO BASIC MODE/ RACE MODE • Measurement using the time r func- tion can be made in RACE MODE. • Indicator will light up as an identifier that shows RACE MODE has been selected. • RACE MODE ca ...

  • Yamaha WR450F (2008) - page 21

    1-11 MULTI-FUNCTION DISPLAY If the machine is run while timer mea - surement is not made, n o change will occur to the digit in tripmeter A (TRIP A). 5. To resume the mea surement, again pushing the "SLCT1" button and "SLCT2" button at the same time. Resetting measurement data Resetting can be made in the follow- ing two manners ...

  • Yamaha WR450F (2008) - page 22

    1-12 MULTI-FUNCTION DISPLAY FUNCTION DIAGRAM A short push on the button changes the operation in the arrowed direction. A short push on the button changes the operation in both arrowed directions. A long push on the button changes the operation in the arrowed direction. A long push on the button changes the operation in both arrowed directions. Met ...

  • Yamaha WR450F (2008) - page 23

    1-13 MULTI-FUNCTION DISPLAY The following diagram illustrates th e multi-function display rega rding the direction and operation condition in- volved in each of its functions. A. A short push on the button changes the operation i n the ar- rowed direction. B. A short push on the button changes the operation i n both arrowed di rections. C. A long p ...

  • Yamaha WR450F (2008) - page 24

    1-14 STARTING AND BREAK-IN STARTING AND BREAK-IN FUEL Always use the recommended fuel as stated below. Also, be sure to use new gasoline the day of a race. Use only unleaded gaso line. The use of leaded g asoline will cause severe damage to the engi ne inter- nal parts such as valv es, piston rings, and exhaust system, etc. If knocking or pingi ng ...

  • Yamaha WR450F (2008) - page 25

    1-15 STARTING AND BREAK-IN The engine fails to start Pull the hot starter lever all the way out and while holding the lever, kick the kickstarter crank 10 to 20 times to clear the engine. Then, re start the en- gine. Refer to "Restarting an engine after a fall". Observe the fo llowing break-in procedures during ini tial opera tion to ensu ...

  • Yamaha WR450F (2008) - page 26

    1-16 TORQUE-CHECK POINTS TORQUE-CHECK POINTS Concerning the tightening torque, refer to "TIGHTENING TORQUES" section in the CHAPTER 2. Frame construction Frame to rear frame Combined seat and fuel tank Fuel tank to frame Exhaust system Silencer to rear frame Engine mounting Frame to engine Engine bracket to engine Engine bracket to frame ...

  • Yamaha WR450F (2008) - page 27

    1-17 CLEANING AND STORAGE CLEANING AND STORAGE CLEANING Frequent cleaning of your machine will enhance its appe arance, maintain good overall perfo rmance, and ex- tend the life of many components. 1. Before washing the machine, block off the en d of the exhaust pipe to prevent water from enter- ing. A plastic bag secured with a rubber band may be ...

  • Yamaha WR450F (2008) - page 28

    2-1 GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model name: WR450FX (CDN, AUS, NZ) WR450F (EUROPE, ZA) Model code numbe r: 5TJK (CDN) 5TJL (EUROPE) 5TJM (AUS, NZ, ZA) Dimensions: CDN, ZA AUS, NZ EUROPE Overall length 2,175 mm (85.63 in) 2,190 mm (86.22 in) 2,200 mm (86.61 in) Overall width 825 mm (32.48 in) ←← Overall height 1, ...

  • Yamaha WR450F (2008) - page 29

    2-2 GENERAL SPECIFICATIONS (Except for CDN) SAE10W30, SAE10W40, SAE15W40, SAE20W40 or SAE20W50 API service SG type or higher, JASO standard MA Oil capacity: Engine oil Periodic oil change 0.95 L (0.84 Imp qt, 1.00 US qt) With oil filter replacement 1.0 L (0.88 Imp qt, 1.06 US qt) Total amount 1.2 L (1.06 Imp qt, 1.27 US qt) Coolant capacity (includ ...

  • Yamaha WR450F (2008) - page 30

    2-3 GENERAL SPECIFICATIONS Chassis: CDN, ZA AUS, NZ EUROPE Frame type Semi double cra- dle ←← Caster angle 27.3 ° 27.0 ° 26.8 ° Trail 117 mm (4.61 in) 116 mm (4.57 in) 115 mm (4.53 in) Tire: Type With tube Size (front) 80/100-21 51M (CDN, ZA) 90/90-21 54R (AUS, N Z, EUROPE) Size (rear) 110/100-18 64M (CDN, Z A) 130/90-18 69R (AUS, NZ, EUROPE ...

  • Yamaha WR450F (2008) - page 31

    2-4 MAINTENANCE SPECIFICATIONS MAINTENANCE S PECIFICATIONS ENGINE Item Standard Limit Cylinder head: Warp limit ---- 0.05 mm (0.002 in) Cylinder: Bore size 95.00–95.01 mm (3.7402 –3.7406 in) ---- Out of round limit ---- 0.05 mm (0.002 in) Camshaft: Drive method Chain drive (Left) ---- Camshaft cap inside diameter 22.000–22.021 mm (0.8661–0. ...

  • Yamaha WR450F (2008) - page 32

    2-5 MAINTENANCE SPECIFICATIONS Valve, valve seat, valve guide: Valve clearance (cold) IN 0.10–0.15 mm (0.0039–0.0059 in ) ---- EX 0.20–0.25 mm (0.0079–0.0098 in ) ---- Valve dimensions: "A" head diameter (IN) 26.9–27.1 mm (1.0591–1.0669 in) ---- "A" head diameter (EX) 27.9–28.1 mm (1.0984–1.1063 in) ---- "B& ...

  • Yamaha WR450F (2008) - page 33

    2-6 MAINTENANCE SPECIFICATIONS Stem runout limit ---- 0.01 mm (0.0004 in) Valve spring: Free length (IN) 39.46 mm (1.55 in) 38.46 mm (1.51 in) Free length (EX) 37.61 mm (1.48 in) 36.61 mm (1.44 in) Set length ( valve closed ) (IN) 27.87 mm (1.10 in) ---- Set length ( valve closed ) (EX) 28.38 mm (1.12 in) ---- Compressed force (installed) (IN) 13 0 ...

  • Yamaha WR450F (2008) - page 34

    2-7 MAINTENANCE SPECIFICATIONS Piston rings: Top ring: Type Barrel ---- Dimensions (B × T) 1.2 × 3.5 mm (0.05 × 0.14 in) ---- End gap (installed) 0.20–0.30 mm (0 .008–0.012 in) 0.55 mm (0.022 in) Side clearance (insta lled) 0.030–0.065 mm (0.0012–0.0026 in) 0.12 mm (0.005 in) 2nd ring: Type Taper ---- Dimensions (B × T) 1.00 × 3.35 mm ...

  • Yamaha WR450F (2008) - page 35

    2-8 MAINTENANCE SPECIFICATIONS Clutch: Friction plate thickness 2.92–3.08 mm (0.115–0.121 in) 2.8 mm (0.110 in) Quantity 8 ---- Clutch plate 1 thickness 1.9–2.1 mm (0.075–0.083 in ) ---- Quantity 4 ---- Warp limit ---- 0.1 mm (0.004 in) Clutch plate 2 thickness 1.5–1.7 mm (0.059–0.067 in ) ---- Quantity 3 ---- Warp limit ---- 0.1 mm (0. ...

  • Yamaha WR450F (2008) - page 36

    2-9 MAINTENANCE SPECIFICATIONS Lubrication system: Oil filter type Paper type ---- Oil pump type Trochoid type ---- Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008 in) Side clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009 in) Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.1 7 mm (0.0067 in) Bypass val ...

  • Yamaha WR450F (2008) - page 37

    2-10 MAINTENANCE SPECIFICATIONS CHASSIS Item Sta ndard Limit Steering system: Steering bearing type Taper roller bearing ---- Front suspension: CDN AUS, NZ, ZA, EUROPE Front fork travel 300 mm (11.8 in) ← ---- Fork spring free length 460 mm (18.1 in) ← 455 mm (17.9 in) Spring rate, STD K = 4.5 N/mm (0.459 kg/ mm, 25.7 lb/in) ← ---- Optional s ...

  • Yamaha WR450F (2008) - page 38

    2-11 MAINTENANCE SPECIFICATIONS ELECTRICAL Drive chain: Type/manufacturer DID520VM/DAIDO ---- Number of links 113 links + joint ---- Chain slack 48–58 mm (1.9–2.3 in) ---- Chain length (15 links) ---- 239.3 mm (9.42 in) Front disc brake: Disc outside dia. × Thickness 250 × 3.0 mm (9.84 × 0.12 in) 250 × 2.5 mm (9.84 × 0.10 in) Pad thickness ...

  • Yamaha WR450F (2008) - page 39

    2-12 MAINTENANCE SPECIFICATIONS Charging system: System type AC magneto ---- Model (stator)/manufacture r 5TJ 50/YAMAHA ---- Normal output 14 V/120 W at 5,000 r/min ---- Charging coil resistance (color) 0.28 8–0.432 Ω at 20 °C (68 °F) (White– Ground) ---- Lighting coil resistance (color) 0.224–0.336 Ω at 20 °C (68 °F) (Yellow– Ground) ...

  • Yamaha WR450F (2008) - page 40

    2-13 TIGHTENING TORQUES TIGHTENING TORQUES ENGINE △ - marked portion shall be checked for torque ti ghtening after brea k-in or before each race. *1: Tighten the cylinder head bo lts to 30 Nm (3.0 m•kg, 22 ft•l b) in the prop er tightening sequence, remove and retighten the cylinder head bolts to 20 Nm (2.0 m•kg, 14 ft•lb) in the proper t ...

  • Yamaha WR450F (2008) - page 41

    2-14 TIGHTENING TORQUES Radiator pipe 1, 2 M10 × 1.0 2 10 1.0 7.2 Impeller M8 × 1.25 1 14 1.4 10 Water pump housing cover M6 × 1.0 3 10 1.0 7.2 Coolant drain bol t M6 × 1.0 1 10 1.0 7.2 Oil pump cove r M4 × 0.7 1 2 0.2 1.4 Oil pump M6 × 1.0 2 10 1.0 7.2 Oil pump drive gear sha ft M6 × 1.0 1 10 1.0 7.2 Engine oil drain bolt (oil filter) M6 × ...

  • Yamaha WR450F (2008) - page 42

    2-15 TIGHTENING TORQUES CHASSIS △ - marked portion shall be checked for torque ti ghtening after brea k-in or before each race. Part to be tightened Thread size Q'ty Tightening torque Nm m•kg ft•lb △ Upper bracket and outer tube M8 × 1.25 4 21 2.1 15 △ Lower bracket and outer tube M8 × 1.25 4 21 2.1 15 △ Upper bracket and steeri ...

  • Yamaha WR450F (2008) - page 43

    2-16 TIGHTENING TORQUES △ Driven sprocket and wheel hub M8 × 1.25 6 50 5.0 36 △ Nipple (spoke) — 72 3 0.3 2.2 △ Disc cover and rear brake caliper M6 × 1.0 2 10 1.0 7.2 △ Protector and rear brake calip er M6 × 1.0 2 7 0.7 5.1 Chain puller adjust bolt and locknut M8 × 1.25 2 19 1.9 13 Engine mounting: △ Engine uppe r bracket and frame ...

  • Yamaha WR450F (2008) - page 44

    2-17 TIGHTENING TORQUES 1. First, tighten the steering ring nut app roximately 38 Nm (3.8 m•kg, 27 ft•l b) by using the steerin g 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 Tighten the rotor nut to 65 Nm (6.5 m•k g, 47 ft•lb), loose n and retighten th ...

  • Yamaha WR450F (2008) - page 45

    2-18 TIGHTENING TORQUES GENERAL TORQUE SPECIFICA TIONS This chart specifies torque for stan- dard fasteners with standard I.S.O. pitch threads. Torque specifications for special components or assem- blies are included in the applicable sections of this book. To avoid warpage, tighten multi-fastener as- semblies in a crisscr oss fashion, in progress ...

  • Yamaha WR450F (2008) - page 46

    2-19 LUBRICATION DIAGRAMS LUBRICATION DIAGRAMS 1. Oil filter element 2. Oil pump 3. Drive axle 4. Main axle 5. Crankshaft 6. Connecting rod A. From cylinder B. To oil tank ...

  • Yamaha WR450F (2008) - page 47

    2-20 LUBRICATION DIAGRAMS 1. Intake camshaft 2. Exhaust camshaft A. To main axle B. From oil pump ...

  • Yamaha WR450F (2008) - page 48

    2-21 CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM 1. Fuel tank breather hose 2. Clamp 3. Diode 4. Hot starter cable 5. Throttle position sensor lead 6. Wire harness 7. Hump (frame) 8. Negative battery lead 9. Starter motor lead 10. Neutral switch le ad 11. AC magneto lead 12. Brake hose 13. Rectifier/regulator lead 14. Carburetor breather hose 15. C ...

  • Yamaha WR450F (2008) - page 49

    2-22 CABLE ROUTING DIAGRAM C. Fasten the diode (at the mark- ing), throttle cable and hot start- er cable onto the frame. Locate the clamp end facing towa rd the lower right of the frame and with the tie end facing downward . D. Fasten the wire harness, throttle position sensor lead and clutch cable onto the frame. Pass the clamp through the hole i ...

  • Yamaha WR450F (2008) - page 50

    2-23 CABLE ROUTING DIAGRAM 1. Throttle cable (pull) 2. Throttle cable (return) 3. Catch tank hose 4. Ignition coil 5. Clamp 6. Air induction hose (air cut-off valve - rear of cylinder he ad) 7. Catch tank breather hose A. Cross the pull and push throttle cables. B. Fasten the catch tank ho se and air induction hose (air cut-off valve-rear of cylind ...

  • Yamaha WR450F (2008) - page 51

    2-24 CABLE ROUTING DIAGRAM 1. Brake ma ster cylinder 2. Brake hose holder 3. Brake ho se A. Install the brake hose so that its pipe portion 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. ...

  • Yamaha WR450F (2008) - page 52

    2-25 CABLE ROUTING DIAGRAM 1. Clamp 2. Positive battery lead 3. Battery 4. Negative battery lead 5. Taillight coupler 6. CDI unit coupler (6-pin) 7. CDI unit coupler (3-pin) 8. CDI unit coupler (6-pin) A. Fasten the wire harness to th e upper engine bracket (left side). Locate the clamp end fa cing to- ward the upper side of the frame with the tie ...

  • Yamaha WR450F (2008) - page 53

    2-26 CABLE ROUTING DIAGRAM E. Connect the wire harness to the starter relay. F. Fasten the catch tank breather hose and catch tank hose to the rear frame. Clamp them close to where they are joined to the frame. Fasten the pipe tightly enough not to crush it. Locate the clamp end facing towa rd the rear of the frame with the tie end facing downward. ...

  • Yamaha WR450F (2008) - page 54

    2-27 CABLE ROUTING DIAGRAM 1. Throttle cable 2. Clamp 3. Brake ho se 4. Clutch cable 5. Hose guide 6. Main switch coupler 7. Wire harness 8. Headlight coupler 9. Hot starter cable 10. Multi-function displ ay bracket 11. Main switch 12. Upper bracket 13. Clutch switch coupler 14. Engine stop switch coupler 15. Multi-function display cou pler 16. Sta ...

  • Yamaha WR450F (2008) - page 55

    2-28 CABLE ROUTING DIAGRAM D. Secure the coupl er by inserting it into the multi-function display bracket. E. Pass the throttle cables, clutch cable and hot starter cable be- tween the upper bracket and multi-function displ ay bracket. F. Fasten the multi-function display leads to the bracket. Cut off the tie end. G. Secure the coupler by pushing i ...

  • Yamaha WR450F (2008) - page 56

    3-1 MAINTENANCE INTERVALS REGULAR INSPECTION AND ADJUSTMENTS MAINTENANCE IN TERVALS The following schedule is intended as a gen eral guide to maint enance and l ubrication. Bear in mind that such factors as weather, terrain, geographical location, and individual u sage will alter the requ ired maintenance and lubrication intervals. If you are a dou ...

  • Yamaha WR450F (2008) - page 57

    3-2 MAINTENANCE INTERVALS CLUTCH Inspect and adjust ●● Insp ect housing, friction plate, clutch plate and spring. Replace ● TRANSMISSION Inspect ● Replace bearing ● SHIFT FORK, SHIFT CAM, GUIDE BAR Inspect ● Inspect wear. ROTOR NUT Retighten ●● MUFFLER Inspect and retighten ●● Clean ● Replace ● CRANK Inspect and clean ●● ...

  • Yamaha WR450F (2008) - page 58

    3-3 MAINTENANCE INTERVALS FUEL TANK, COCK Clean and insp ect ●● BRAKES Adjust lever position a nd pedal height ●● Lubricate pivot point ●● Check brake disc surface ●● Check fluid level and leakage ●● Retighten brake d isc bolts, cali- per bolts, master cylinder bolts and union bolts ●● Replace pads ● Replace brake fluid ? ...

  • Yamaha WR450F (2008) - page 59

    3-4 MAINTENANCE INTERVALS TIRE, WHEELS Inspect air pressure , wheel run- out, tire wear and spoke loose- ness ●● Retighten sprocke t bolt ●● Inspect bearings ● Replace bearings ● Lubricate ● Lithium ba se grease THROTTLE, CONTROL CABLE Check routing and connectio n ●● Lubricate ●● Yamaha cable lube or SAE 10W-30 motor oil HOT ...

  • Yamaha WR450F (2008) - page 60

    3-5 PRE-OPERATION INSPECTION AND MAINTENANCE PRE-OPERATION INSPECTION AND MAINTENANCE Before riding for break-in operation or practice, make sure the machine is in goo d operating condition. Before using this machine, ch eck the following points. GENERAL INSPECTION AND MAINTENANCE Item Routine Page Coolant Check that coolant is fill ed up to the ra ...

  • Yamaha WR450F (2008) - page 61

    3-6 ENGINE ENGINE REMOVING THE SEAT, FUEL TANK AND SIDE COVERS Order Part name Q'ty Remarks Turn the fuel cock to "OFF". Disconnect the fuel hose. 1S e a t 1 2 Air scoop (left and right) 2 3 Bolt (fuel tank) 2 4 Fuel tank 1 5 Left side cover 1 Open the air filter case cover. 6 Right side cover 1 Refe r to removal section. 7 Headlight ...

  • Yamaha WR450F (2008) - page 62

    3-7 ENGINE REMOVING THE SIDE COVER 1. Remove: • Bolt (side cover) • Right side cover "1" Draw the side cover backward to re- move it because its claw "a" is insert- ed in the air filter case. ...

  • Yamaha WR450F (2008) - page 63

    3-8 ENGINE REMOVING THE EXHAUST PIPE AND SILENCER Order Part name Q'ty Remarks Right side cover Refer to "REMOVING THE SEAT, FUEL TANK AND SIDE COVERS" section. 1 Bolt (silencer clamp) 1 Onl y 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) 1 8 Bolt (ex ...

  • Yamaha WR450F (2008) - page 64

    3-9 ENGINE CHECKING THE SILENCER AND EXHAUST PIPE 1. Inspect: • Gasket "1" Damage → Replace. INSTALLING THE SILENCER AND EXHAUST PIPE 1. Install: • Gasket • Exhaust pipe "1" • Nut (exhaust pipe) "2" • Bolt (exhaust pipe) "3" First, temporarily tighten the nut (ex- haust pipe), then tighten the bol ...

  • Yamaha WR450F (2008) - page 65

    3-10 ENGINE Handling note s of coolant: The coolant is harmful so it should be handled with sp ecial care. • When cool ant splashes to your eye. Thoroughly wash your eye wi th water and see your do ctor. • When cool ant splashes to your clothes. Quickly wash it away with water and then with soap. • When co olant is swallowed . Quickly make hi ...

  • Yamaha WR450F (2008) - page 66

    3-11 ENGINE 2. Adjust: • Throttl e grip free play Throttle grip free play adjus tment steps: a. Slide the adjuster cover. b. Loosen the locknut "1". c. Tu rn the adjuster "2" until the specified free play is obtained. d. Tighten the lockn ut. Before adjusting the th rottle cable free play, the engine idle speed should be adjus ...

  • Yamaha WR450F (2008) - page 67

    3-12 ENGINE 5. Inspect: • Air filter element Damage → Replace. 6. Apply: • Foam-air-filter oil or equivalent oil to the el ement • Squeeze out the e xcess oil. Ele- ment shoul d be wet but not drip- ping. • Wipe off the oil left on the element surface using a clean dry cloth. (Ex- cess oil in the element may ad- versely affect engine star ...

  • Yamaha WR450F (2008) - page 68

    3-13 ENGINE • Do not add any chemical add i- tives or use oils with a grade of CD "a" or higher. • Do not use oi ls labeled "ENERGY CONSERVING II" "b" or higher. Engine oil also lubricates the clutch and additives could cause clutch slippage. • Do not allow foreign material to enter the crankcase. 5. Start the en ...

  • Yamaha WR450F (2008) - page 69

    3-14 ENGINE ADJUSTING THE PILOT SCREW 1. Adjust: • Pilot screw "1" Adjustme nt steps: To optimize the fuel flo w at a smaller throttle opening, e ach machine's pilot screw has been individuall y set at the factory. Before adju sting the pilo t screw, turn it in fully and count the number of turns. Record this number as the factory- ...

  • Yamaha WR450F (2008) - page 70

    3-15 ENGINE 5. Adjust: • Valve clearance Adjustme nt steps: a. Remove the camshaft (intake and exhaust). Refer to "CAMSHAFTS" section in the CHAPTER 5. 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 l ...

  • Yamaha WR450F (2008) - page 71

    3-16 ENGINE INTAKE EXHAUST ...

  • Yamaha WR450F (2008) - page 72

    3-17 CHASSIS CLEANING THE SPARK ARRESTER (For USA) • Be sure the exhaust pipe and si- lencer a re cool before cleaning the spark arre ster. • Do not sta rt the engine whe n cleaning the exhaus t system. 1. Remove: • Screw (silencer ca p) "1" 2. Remove: • Bolt (spark arrester) "1" 3. Remove: • Tail pipe "1" ? ...

  • Yamaha WR450F (2008) - page 73

    3-18 CHASSIS 2. Remove: • Brake lever cover 3. Adjust: • Brake lever position Brake lever position adjustment steps: a. Loosen the locknut "1". b. Turn the adjusti ng bolt "2" until the lever position "a" is within speci- fied position. c. Ti ghten the locknut. Be sure to tighten the locknut, as it will cause poor ...

  • Yamaha WR450F (2008) - page 74

    3-19 CHASSIS i. Insta ll the brake caliper "8" and tighten the pad pin "9". j. Insta ll 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 ...

  • Yamaha WR450F (2008) - page 75

    3-20 CHASSIS 3. Inspect: • Brake fluid level Refer to "CHECKING THE BRAKE FLUID LEVEL" section. 4. Check: • Brake pedal operation A softy or spongy feeling → Bleed 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 ...

  • Yamaha WR450F (2008) - page 76

    3-21 CHASSIS When installing th e drive chain, apply the lithium soap base grease on th e chain joint and O-rings. 7. Install: • Link plate • Press the link plate onto the chain joint using a drive chain riveter "5". • Rivet the end of the chain joint us- ing a drive chai n riveter. • After riveting the chain joint, make sure its ...

  • Yamaha WR450F (2008) - page 77

    3-22 CHASSIS 1. Elevate the front wheel by placing a suitable stand under the engine. 2. Remove the air bleed screw "1" and release the internal pressure from the front fork. 3. Install: • Air bleed screw ADJUSTING THE FRONT FORK REBOUND DAMPING FORCE 1. Adjust: • Rebound dampin g force By turning the adjuster "1". • STAND ...

  • Yamaha WR450F (2008) - page 78

    3-23 CHASSIS Never attempt to turn the adjuster beyond the maximum or minimum setting. 5. Tighten: •L o c k n u t 6. Install: • Rear frame (upper) • Rear frame (lower) ADJUSTING THE REAR SHOCK ABSORBER REBOUND DAMPING FORCE 1. Adjust: • Rebound dampin g force By turning the adjuster "1". • STANDARD POSITION: This is the position ...

  • Yamaha WR450F (2008) - page 79

    3-24 CHASSIS CHECKING THE TIRE PRESSURE 1. Measure: • Tire pressure Out of specification → Adjust. • Check the tire while it is cold. • Loose bead stoppers a llow the tire to slip off its position on t he 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 tir ...

  • Yamaha WR450F (2008) - page 80

    3-25 CHASSIS • The handlebar upper holder should be installed with the punched mark "a" forward. • Install the handleb ar so that the marks "b" are in place on both sides. • Install the han dlebar so that the pro- jection "c" of the handlebar upper holder is positioned at the mark on the handlebar a s shown. • ...

  • Yamaha WR450F (2008) - page 81

    3-26 CHASSIS LUBRI CATION To ensure smooth operation of all components, lubricate your machine during setup, afte r break-in, and after every race. 1. All control cable 2. Clutch lever pivot 3. Shift pedal pivot 4. Footrest pivot 5. Throttle-to-handlebar contact 6. Drive chain 7. Tube guide ca ble winding por- tion 8. Throttle cable end 9. Clutch c ...

  • Yamaha WR450F (2008) - page 82

    3-27 ELECTRICAL ELECTRICAL CHECKING THE SPARK PLUG 1. Remove: • Spark plug 2. Inspect: • Electrode "1" Wear/damage → Replace. • Insulator color "2" Normal condition is a medium to light tan color. Distinctly different color → Check the engine condition. When the engine runs for many hours at low speeds, the spark plug ...

  • Yamaha WR450F (2008) - page 83

    3-28 ELECTRICAL 3. Remove: • Battery band •B a t t e r y 4. Measure: • Battery charge Measurement steps: a. Connect a pocket tester "1" to the battery terminals. • The charge state of an MF battery can be checked by measuring its open-circuit voltage (i.e., the vol t- age when the positive terminal is disconnected). • No chargin ...

  • Yamaha WR450F (2008) - page 84

    3-29 ELECTRICAL Charging method using a variabl e voltage charger ...

  • Yamaha WR450F (2008) - page 85

    3-30 ELECTRICAL Charging method usin g a constant voltage charger ...

  • Yamaha WR450F (2008) - page 86

    3-31 ELECTRICAL 6. Install: •B a t t e r y • Battery band 7. Connect: • Battery leads (to the batte ry terminals) First, connect the positiv e lead "1", then the negative lead "2". 8. Check: • Battery terminals Dirt → Clean with a wire brush. Loose connection → Connect properly. 9. Lubricate: • Battery terminal 10. ...

  • Yamaha WR450F (2008) - page 87

    3-32 ELECTRICAL ADJUSTING THE HEADLIGHT BEAMS 1. Adjust: • Headlight beam (ve rtically) Adjusting steps: a. Turn the adjustin g screw "1" in di- rection "a" or "b". Direction "a" Headlight beam is raised. Direction "b" Headlight beam is lowered. ...

  • Yamaha WR450F (2008) - page 88

    4-1 ENGINE TUNING ENGINE CARBURETOR SETTING • The air/fuel mixture will vary de- pending on atmospheric conditi ons. Therefore, it is necessary to take into consideration the air pressure, ambient temperature, hu midity, etc., when adjusting the carburetor. • Perform a test run to check for prop- er engine performance (e.g., throt- tle response ...

  • Yamaha WR450F (2008) - page 89

    4-2 ENGINE ADJUSTING THE PILOT JET The richness of the air-fuel mixtu re with the throttle open 1/4 or less can be set by adjusti ng the pilot jet "1". Effects of adjusting the pilot jet (reference) A. Idle B. Fully open 1. #48 2. #42 3. #45 ADJUSTING THE JET NEEDLE GROOVE POSITION Adjusting the jet needl e "1" position affects ...

  • Yamaha WR450F (2008) - page 90

    4-3 ENGINE CARBURETOR SETTING PARTS Main jet Size Part number (-14943-) Rich #185 4MX-44 #182 4MX-94 #180 4MX-43 #178 4MX-93 #175 4MX-42 #172 4MX-92 #170 4MX-41 #168 4MX-91 #165 4MX-40 (STD) #162 4MX-90 *(STD) Lean #160 4MX-39 Pilot jet Size Part number (-14948-) Rich #55 4MX-09 #52 4MX-08 #50 4MX-07 *(STD) #48 4MX-06 (STD) Lean #45 4MX-05 Jet need ...

  • Yamaha WR450F (2008) - page 91

    4-4 ENGINE EXAMPLES OF CARBURETOR SETTING DEPENDING ON SYMPTOM * This should be taken simply for an example. It is necessary to set the carbureto r while checking the operating conditions of the engine. Symptom Setting Checking At full throttle Hard breathing Shearing noise Whitish spark plug ↓ Lean mixture Increase main jet cal ibration no. (Gra ...

  • Yamaha WR450F (2008) - page 92

    4-5 CHASSIS CHASSIS SELECTION OF THE SECONDARY REDUCTION RATIO (SPROCKET) <Requirement for selection of sec- ondary gear reduction ra tio> • It is generally said that the second- ary gear ratio should be reduced for a longer straight portion of a speed course and should be in creased for a course with many corners. Actual - ly, however, as ...

  • Yamaha WR450F (2008) - page 93

    4-6 CHASSIS A. Air spring characteristics in relation to oil l evel change B. Load C. Stroke 1. Max. oil level 2. Standard oil level 3. Min. oil level ADJUSTING THE SPRING PRELOAD The spring preload is adjusted by in- stalling the adjustment washer "1 " be- tween the fork spring "2" and damper rod "3". Do not install t ...

  • Yamaha WR450F (2008) - page 94

    4-7 CHASSIS 2. Setting of damping force • Change the rebound damping. • Change the compression damp- ing. CHOOSING SET LENGTH 1. Place a stand or bl ock under the engine to put the rear wheel above the floor, and measure the length "a" between the rear wheel axle center and the re ar fender holding bolt. 2. Remove the stand or bl ock ...

  • Yamaha WR450F (2008) - page 95

    4-8 CHASSIS SUSPENSION SETTING (FRONT FORK) • If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure gi ven in the same chart. • Before any change, set t he rear shock absorber sunken length to the standard figure 90–100 mm (3.5–3.9 in). Symptom Section ...

  • Yamaha WR450F (2008) - page 96

    4-9 CHASSIS SUSPENSION SETTING (REAR SHOCK ABSORBER) • If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure gi ven in the same chart. • Adjust the rebound damping in 2-click increments or decrements. • Adjust the low compression damping in 1-click incre ...

  • Yamaha WR450F (2008) - page 97

    5-1 RADIATOR ENGINE RADIATOR REMOVING THE RADIATOR Order Part name Q'ty Remarks Drain the coolant. Refer to "CHANGING THE COOLANT" sec - tion in the CHAPTER 3. Seat, fuel tank and left side cover Refer to "REMOVING THE SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 3. Exhaust pipe Refer to "REMOVING THE EXHAUS ...

  • Yamaha WR450F (2008) - page 98

    5-2 RADIATOR 11 Pipe 1/O-ring 1/1 12 Catch tank breather hose 1 13 Catch tank 1 Order Part name Q'ty Remarks ...

  • Yamaha WR450F (2008) - page 99

    5-3 RADIATOR HANDLING NOTE Do not remove the radiator cap when the engine and ra diator are hot. Scaldi ng hot fluid and ste am may be blown out under pressure, which could ca use serious in jury. When the engin e has cooled, open the radiator cap by th e following procedure: Place a thick rag, like a towel, over the radiator cap, sl owly rotate th ...

  • Yamaha WR450F (2008) - page 100

    5-4 CARBURETOR CARBURETOR REMOVING THE CARBURETOR Order Part name Q'ty Remarks Seat and fuel ta nk Refer to "REMOVING THE SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 3. Rear shock absorber Refer to "REAR SHOCK ABSORBER" sec- tion in the CHAPTER 6. 1C l a m p 2 2 Throttle position sensor lead coupler 1 3 Throttle ...

  • Yamaha WR450F (2008) - page 101

    5-5 CARBURETOR 13 Bracket (cylinder head breather pipe) 1 14 Carburetor joint 1 Order Part name Q'ty Remarks ...

  • Yamaha WR450F (2008) - page 102

    5-6 CARBURETOR DISASSEMBLING THE CARBURETOR Order Part name Q'ty Remarks 1 Carburetor breather hose 4 2 Valve lever housing cover 1 3 Screw (throttle shaft) 1 4 Throttle valve 1 5 Need le holder 1 6 Jet needle 1 7 Accelerator pump cover 1 8S p r i n g 1 9 Diaphragm (accelerator pump) 1 10 Air cut valve cover 1 11 Spring (air cut valve) 1 12 Di ...

  • Yamaha WR450F (2008) - page 103

    5-7 CARBURETOR 19 Main jet 1 20 Needle jet 1 21 Spacer 1 22 Pilot jet 1 23 Starter jet 1 24 Push rod 1 Pull the push rod. 25 Throttle shaft assembly 1 26 Push rod link lever assembly 1 27 Pilot air jet 1 28 Cold starter plunger 1 Order Part name Q'ty Remarks ...

  • Yamaha WR450F (2008) - page 104

    5-8 CARBURETOR HANDLING NOTE Do not loosen th e screw (throttle position sensor) "1" except when changing the th rottle position sen- sor due to failur e because it will cause a drop in engine pe rfor- mance. REMOVING THE PILOT SCREW 1. Remove: • Pilot screw "1" To optimize th e fuel flow at a small throttle opening, e ach mac ...

  • Yamaha WR450F (2008) - page 105

    5-9 CARBURETOR e. If both are fine, adjust the float height by bending th e float tab "b" on the float. f. Recheck the float height. CHECKING THE FLOAT 1. Inspect: • Float "1" Damage → Replace. CHECKING THE STARTER PLUNGER 1. Inspect: • Cold starter plunger "1" • Hot starter plunger "2" Wear/damage ? ...

  • Yamaha WR450F (2008) - page 106

    5-10 CARBURETOR • Apply the fluoro chemical grease on the bearings. • Fit the projection "a" on the throttle shaft assembly into the slot "b" in the throttle posit ion sensor. • Make sure the stopper "c" of the spring fits into the recess in the car- buretor . • Turn the throttle shaft assembl y left while hold ...

  • Yamaha WR450F (2008) - page 107

    5-11 CARBURETOR 17. Install: • Throttle valve assembly "1" • Screw (throt tle shaft) "2" Install the valve lever rollers "3" into the slits "a" of the throttle valve. 18. Install: • O-ring "1" • Valve lever housing cover "2" • Bolt (valve lever housing cov er) "3" 19. I ...

  • Yamaha WR450F (2008) - page 108

    5-12 CARBURETOR 7. Install: • Throttle cable cover "1" • Bolt (thr ottle cable cover) "2" 8. Install: • Throttle po sition sensor lead cou- pler "1" • Clamp "2 " Refer to "CABLE R OUTING DIA- GRAM" section in the CHAPTER 2. 9. Install: • Clamp "1 " Refer to "CABLE R OUTING D ...

  • Yamaha WR450F (2008) - page 109

    5-13 AIR INDICTOIN SYSTEM AIR INDICTOIN SYSTEM REMOVING THE AIR INDUCTION SYSTEM Order Part name Q'ty Remarks 1 Bracket 1 2 Air cut-off valve assembly 1 3 Air induction hose (ai r cut-off valve - front of cyl- inder head) 1 4 Air induction pipe 1 5 Gasket 1 6 Air induction hose (air cut-off valve - rear of cylin- der head) 1 7 Air induction ho ...

  • Yamaha WR450F (2008) - page 110

    5-14 AIR INDICTOIN SYSTEM CHECKING THE AIR INDUCTION SYSTEM 1. Inspect: • Air induction hose Crack/damage → Replace. • Air induction pipe Crack/damage → Replace. 2. Check: • Operation of air cut valve Pass air through the pipe and check the air cut valve for opera- tion. Does not meet the followi ng con- dition → Replace the air cut val ...

  • Yamaha WR450F (2008) - page 111

    5-15 CAMSHAFTS CAMSHAFTS REMOVING THE CYLINDER HEAD COVER Order Part name Q'ty Remarks Seat and fuel ta nk Refer to "REMOVING THE SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 3. Air cut-off valve assembly Refer to "AIR INDUCTION SYSTEM" section. Engine upper bracket (right) Refer to "ENGINE REMOVAL" se ...

  • Yamaha WR450F (2008) - page 112

    5-16 CAMSHAFTS REMOVING THE CAMSHAFTS Order Part name Q'ty Remarks 1 Timing mark accessing screw 1 Refer to removal section. 2 Crankshaft 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 Gasket 1 Refer to removal section. 6 Bolt ...

  • Yamaha WR450F (2008) - page 113

    5-17 CAMSHAFTS REMOVING THE CAMSHAFT 1. Remove: • Timing mark accessing screw "1" • Crankshaft end accessing screw "2" 2. Align: • T.D.C. mark With align mark. Checking steps: a. Turn the crankshaft counterclock- wise with a wren ch. b. Align the T.D.C. mark "a" on th e rotor with the align mark "b" on ...

  • Yamaha WR450F (2008) - page 114

    ...

  • Yamaha WR450F (2008) - page 115

    5-19 CAMSHAFTS Do not turn the cranksha ft during the camshaft insta llation. Damage or improper valve timing will re- sult. d. Install the clips, camshaft caps "4" and bolts (camshaft cap) "5". • Before removing the clip s, cover the cylinder head with a clean rag to prevent the clips from into the cylin- der head cavity. • ...

  • Yamaha WR450F (2008) - page 116

    5-20 CYLINDER HEAD CYLINDER HEAD REMOVING THE CYLINDER HEAD Tighten the cylinder head bolts to 30 Nm (3.0 m•kg, 22 ft•lb ) in the proper ti ghtening sequenc e, remove and retighten the cylinder head bolts to 20 Nm (2.0 m•kg , 14 ft•lb) in the prop er tightening sequ ence, and then tighten th e cylinder head bolts further to reach the specif ...

  • Yamaha WR450F (2008) - page 117

    5-21 CYLINDER HEAD CHECKING THE CYLINDER HEAD 1. Eliminate: • Carbon deposits (from the com- bustion chambers) Use a rounded scraper. Do not use a sharp instrument to avoid damaging or scratching: • Spark plug threads • Valve seats 2. Inspect: • Cylinder head Scratches/damage → Replace. 3. Measure: • Cylinder head warpage Out of specifi ...

  • Yamaha WR450F (2008) - page 118

    5-22 CYLINDER HEAD 3. Install: • Bolt (cylinder head) "1" Bolt (cylinder head): 10 Nm (1.0 m•kg, 7.2 ft•lb) ...

  • Yamaha WR450F (2008) - page 119

    5-23 VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS REMOVING THE VALVES AND VALVE SPRINGS Order Part name Q'ty Remarks Cylinder head Refer to "CYLINDER HEAD" section. 1 Valve lifter 5 Refer to removal sectio n. 2 Adjusting pad 5 Refer to removal section. 3 Valve cotter 10 Refer to removal section. 4 Valve spring retainer 5 5 Valve ...

  • Yamaha WR450F (2008) - page 120

    5-24 VALVES AND VALVE SPRINGS REMOVING THE VALVE LIFTER AND VALVE COTTER 1. Remove: • Valve lifter "1" • Pad "2" Identify each lifter "1" and pad "2" po- sition very carefully so that they can be reinstalled in their original pla ce. 2. Check: • Valve sealing Leakage at the valve seat → In- spect the ...

  • Yamaha WR450F (2008) - page 121

    5-25 VALVES AND VALVE SPRINGS 4. Measure: • Margin thickness "a" Out of specification → Replace. 5. Measure: • Runout (valve stem) Out of specification → Replace. • When installing a new valve always replace the guide. • If the valve is removed or replaced always replace the oil seal. 6. Eliminate: • Carbon deposits (from th ...

  • Yamaha WR450F (2008) - page 122

    5-26 VALVES AND VALVE SPRINGS CHECKING THE VALVE SPRINGS 1. Measure: • Valve spring free length "a" Out of specification → Replace. 2. Measure: • Compressed spring force "a" Out of specification → Replace. b. Installed length 3. Measure: • Spring tilt "a" Out of specification → Replace. CHECKING THE VALVE L ...

  • Yamaha WR450F (2008) - page 123

    5-27 CYLINDER AND PISTON CYLINDER AND PISTON REMOVING THE CYLINDER AND PISTON Order Part name Q'ty Remarks Cylinder head Refer to "CYL INDER HEAD" section. 1 Bolt (cylinder) 1 2 Cylinder 1 3 Gasket 1 4 Dowel pin 2 5 Piston pin clip 2 Refer to removal section. 6 Piston pin 1 Refer to removal section. 7 Piston 1 Refer to removal sectio ...

  • Yamaha WR450F (2008) - page 124

    5-28 CYLINDER AND PISTON REMOVING THE PISTON AND PISTON RING 1. Remove: • Piston pin clip "1" • Piston pin "2" • Piston "3" • Put identification marks on each piston head for reference during re- installation. • Before removing each piston pin, deburr the clip groove and pin hole area. If the piston pin groov ...

  • Yamaha WR450F (2008) - page 125

    5-29 CYLINDER AND PISTON 3. Measure: • Ring end gap Out of specification → Replace. You cannot measure the end gap on the expander spacer of the oil control ring. If the oil control ring rails show excessive gap, replace all three rings. CHECKING THE PISTON PIN 1. Inspect: • Piston pin Blue discoloration/gro oves → Re- place, then inspect t ...

  • Yamaha WR450F (2008) - page 126

    5-30 CLUTCH CLUTCH REMOVING THE CLUTCH Order Part name Q'ty Remarks Drain the engine oil . Refer to "CHANGING THE ENGINE OIL" section in the CHAPTER 3. Brake pedal Refer to "ENGINE REMOVAL" section. Clutch cable Disconnect at engine side. 1 Clutch cover 1 2 Gasket 1 3 Dowel pin 2 4 Clutch spring 6 5 Pressure plate 1 6 Push ...

  • Yamaha WR450F (2008) - page 127

    5-31 CLUTCH 14 Nut (clutch boss) 1 Refer to removal section. 15 Lock washer 1 Refer to removal sectio n. 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 ...

  • Yamaha WR450F (2008) - page 128

    5-32 CLUTCH REMOVING THE CLUTCH BOSS 1. Remove: •N u t " 1 " • Lock washer "2" • Clutch boss "3" Straighten the lock washer tab and use the clutch holding tool "4" to hold the clutch boss. A. For USA and CDN B. Except for USA and CDN CHECKING THE CLUTCH HOUSING AND BOSS 1. Inspect: • Clutch housing &q ...

  • Yamaha WR450F (2008) - page 129

    5-33 CLUTCH 2. Install: • Lock washer "1" • Nut (clutch boss) "2" Make sure to tighten to specifica- tion; otherw ise, it may damage the other part that is fastened togeth- er. • Install the lock washer with its con- caves fitted over the convexes of the clutch boss. • Use the clutch holding tool "3" to hold th ...

  • Yamaha WR450F (2008) - page 130

    5-34 OIL FILTER ELEMENT AND WATER PUMP OIL FILTER ELEMENT AND WATER PUMP REMOVING THE OIL FILTER ELEMENT AND WATER PUMP Order Part name Q'ty Remarks Right engine guard Refer to "ENGINE REMOVAL" section. Drain the engine oil . Refer to "CHANGING THE ENGINE OIL" section in the CHAPTER 3. Drain the coolant. Refer to "CHAN ...

  • Yamaha WR450F (2008) - page 131

    5-35 OIL FILTER ELEMENT AND WATER PUMP 9 Gasket 1 10 Dowel pin/O-ring 3/1 11 Impeller 1 Refer to removal section. 12 Washer 1 Refer to removal section. 13 Impeller shaft 1 Refer to removal section. 14 Oil seal 1 1 Refer to removal sectio n. 15 Oil seal 2 1 Refer to removal sectio n. 16 Bearing 1 Refer to removal section. Order Part name Q'ty R ...

  • Yamaha WR450F (2008) - page 132

    5-36 OIL FILTER ELEMENT AND WATER PUMP REMOVING THE IMPELLER SHAFT 1. Remove: • Impeller "1" • Washer "2" • Impeller shaft "3" Hold the impeller shaft on its width across the flats "a" with spanners, etc. and remove the impeller. REMOVING THE OIL SEAL It is not necessary to disassemble the water pump, u ...

  • Yamaha WR450F (2008) - page 133

    5-37 OIL FILTER ELEMENT AND WATER PUMP 2. Install: • Right crankcase cover "1" •B o l t " 2 " •B o l t • Apply the engine oil on the impeller shaft end. • When installing the crankcase cov- er onto the crankca se, be sure that the impeller shaft end "2" aligns with the balancer end slot "3". • Tig ...

  • Yamaha WR450F (2008) - page 134

    5-38 BALANCER BALANCER REMOVING THE BALANCER Order Part name Q'ty Remarks Primary driven gear Refer to "CLUTCH" secti on. Right crankcase cover Refer to "OIL FILTER ELEMENT AND WA- TER PUMP" section. Stator Refer to "CDI MAGNETO" section. 1 Nut (balancer) 1 Refer to removal section. 2 Nut (primary drive gear) 1 R ...

  • Yamaha WR450F (2008) - page 135

    5-39 BALANCER REMOVING THE BALANCER 1. Straighten the lock wa sher tab. 2. Loosen: • Nut (balancer) "1" • Nut (primary drive gear) "2" • Nut (balancer shaft driven gear) "3" Place an aluminum plate "a" b etween the teeth of the balancer shaft drive gear "4" and driven gear "5". CHECK ...

  • Yamaha WR450F (2008) - page 136

    5-40 OIL PUMP OIL PUMP REMOVING THE OIL PUMP Order Part name Q'ty Remarks Primary driven gear Refer to "CLUTCH" section. 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 Dowel pin 2 6 Outer rotor 2 1 7 Circlip 1 8 Inner rotor ...

  • Yamaha WR450F (2008) - page 137

    5-41 OIL PUMP 15 Oil pump drive shaft 1 16 Rotor housing 1 Order Part name Q'ty Remarks ...

  • Yamaha WR450F (2008) - page 138

    5-42 OIL PUMP CHECKING THE OIL PUMP 1. Inspect: • Oil pump drive gear • Oil pump drive shaft • Rotor housing • Oil pump cover Cracks/wear/damage → Replace. 2. Measure: • Tip clearance "a" (between the inner rotor "1" and outer rotor "2") • Side clea rance "b" (between the outer rotor "2&quo ...

  • Yamaha WR450F (2008) - page 139

    5-43 KICK SHAFT AND SHIFT SHAFT KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT AND SHIFT SHAFT Order Part name Q'ty Remarks Oil pump Refer to "OIL PUMP" section. 1 Kick idle gear 1 2 Kick shaft assembly 1 Ref er to removal section. 3 Spring guide 1 4 Torsion spring 1 5 Ratch et wheel 1 6 Kick gear 1 7 Kick shaft 1 8 Washer 1 9 Sh ...

  • Yamaha WR450F (2008) - page 140

    5-44 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 ...

  • Yamaha WR450F (2008) - page 141

    5-45 KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT ASSEMBLY 1. Remove: • Kick shaft assembly "1" Unhook the torsion spring "2" from the hole "a" in the crankcase. REMOVING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY 1. Remove: • Bolt (shift guide) • Shift gui de "1" • Shift lever assembly "2&qu ...

  • Yamaha WR450F (2008) - page 142

    5-46 KICK SHAFT AND SHIFT SHAFT INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY 1. Install: • Spring "1" • Pawl pin "2" •P a w l " 3 " To shift lever "4". Apply the engine oil on the spring, pawl pin and p awl. 2. Install: • Shift lever assembly "1" To shift guide "2". 3. Insta ...

  • Yamaha WR450F (2008) - page 143

    5-47 KICK SHAFT AND SHIFT SHAFT INSTALLING THE KICK IDLE GEAR 1. Install: • Kick idle gear "1" • Washer "2" • Circlip "3" • Apply the e ngine oil on the kick idle gear inner circumference. • Install the kick idle gear with its de- pressed side "a " toward you. ...

  • Yamaha WR450F (2008) - page 144

    5-48 AC MAGNETO AND STARTER CLUTCH AC MAGNETO AND STARTER CLUTCH REMOVING THE AC MAGNETO AND STARTER CLUTCH Order Part name Q'ty Remarks Drain the engine oil . Refer to "CHANGING THE ENGINE OIL" section in the CHAPTER 3. Seat and fuel ta nk Refer to "REMOVING THE SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 3. Di ...

  • Yamaha WR450F (2008) - page 145

    5-49 AC MAGNETO AND STARTER CLUTCH Tighten the rotor nut to 65 Nm (6.5 m•kg, 47 ft•lb), loosen and retighten th e rotor nut to 65 Nm (6.5 m•kg, 47 ft•lb). 12 Woodruff key 1 13 Starter clutch assembly co ver 1 Refer to removal section. 14 Starter clutch 1 Refer to removal section. 15 Starter clutch drive gear 1 16 Holder 1 17 Pickup coil 1 1 ...

  • Yamaha WR450F (2008) - page 146

    5-50 AC MAGNETO AND STARTER CLUTCH REMOVING THE ROTOR 1. Remove: • Nut (rot or) "1" • Washer Use the sheave holder "2". 2. Remove: • Rotor "1" Use the rotor puller "2". REMOVING THE STARTER CLUTCH 1. Remove: • Starter cl utch a ssembly cover "1" Insert a thin screwdriver or the like under th ...

  • Yamaha WR450F (2008) - page 147

    5-51 AC MAGNETO AND STARTER CLUTCH • Pass the AC magneto lead "5" un- der the pickup coil. • Pass the AC magneto lead "4" un- der the holder as shown. • Take care not to catch the AC mag- neto lead between crankcase cover ribs. • Tighten the bolt (stator) usi ng the T25 bit. • Apply the sealant to the grommet of the AC ...

  • Yamaha WR450F (2008) - page 148

    5-52 AC MAGNETO AND STARTER CLUTCH Install the co ver (idle gear 1) wi th its mark "a" facing upw ard. 11. Connect: • AC magneto lead Refer to "CABLE R OUTING DIA- GRAM" section in the CHAPTER 2. 12. Install: • Shift pedal "1" • Bolt (shift pedal) When installing the shift pedal onto the shift shaft, be su re tha ...

  • Yamaha WR450F (2008) - page 149

    5-53 ENGINE REMOVAL ENGINE REMOVAL REMOVING THE ENGINE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the frame. Refer to "HANDLING NOTE". Drain the engine oil . Refer to "CHANGING THE ENGINE OIL" section in the CHAPTER 3. Seat and fuel ta nk Refer to "REMOVING THE SEAT, FUEL TANK AND ...

  • Yamaha WR450F (2008) - page 150

    5-54 ENGINE REMOVAL Ignition coil Disconnect the AC magneto lead. Disconnect the starter motor lead. Refer to "ELECTRIC STARTING SYSTEM" section in the CHAPTER 7. Negative battery lead Disconnect at the engine side. 1 Engine guard 1 2 Neutr al switch 1 3 Drive chain sprocket cover 1 4 Nut (drive sprocket) 1 Ref er to removal section. 5 Lo ...

  • Yamaha WR450F (2008) - page 151

    5-55 ENGINE REMOVAL HANDLING NOTE Support the machine securely so there is no dange r of it falling over. REMOVING THE DRIVE SPROCKET 1. Remove: • Nut (drive sprocket) "1" • Lock washer "2" • Straighten the lock washer tab . • Loosen the nut while applyi ng the rear brake. 2. Remove: • Drive sprocket "1" • ...

  • Yamaha WR450F (2008) - page 152

    5-56 ENGINE REMOVAL 2. Install: • Lock washer "1" • Nut (drive sprocket) "2" Tighten the nut while applying the rear brake. Make sure to tighten to specifica- tion; otherw ise, it may damage the other part that is fastened togeth- er. 3. Bend the lock washer tab to lock the nut. 4. Install: • Drive chain sprocket guide • ...

  • Yamaha WR450F (2008) - page 153

    5-57 CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT REMOVING THE CRANKSHAFT Order Part name Q'ty Remarks Engine Refer to "ENGINE REMOVAL" section. Piston Refer to "CYLINDE R AND PISTON" section. Balancer Refer to "BALANCER" section. Kick shaft assembly Refer to "KICK SHAFT AND SHIFT SHAFT" section. Se ...

  • Yamaha WR450F (2008) - page 154

    5-58 CRANKCASE AND CRANKSHAFT 9 Left crankcase 1 Refer to removal section. 10 Oil strainer 1 11 Balancer shaft 1 Refer to removal section. 12 Crankshaft 1 Refer to removal sectio n. Order Part name Q'ty Remarks ...

  • Yamaha WR450F (2008) - page 155

    5-59 CRANKCASE AND CRANKSHAFT REMOVING THE 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 3 2 Bearing 10 Refer to remova l section. ...

  • Yamaha WR450F (2008) - page 156

    5-60 CRANKCASE AND CRANKSHAFT DISASSEMBLING THE CRANKCASE 1. Separate: • Right crankcase • Left crankcase Separation steps: a. Remove the crankcase bolts, hose guide an d clutch cable hold - er. Loosen each bolt 1/4 of a turn at a time and after all the bolts are loos- ened, remove them. b. Remove the right crankcase. • Place the crankcase wi ...

  • Yamaha WR450F (2008) - page 157

    5-61 CRANKCASE AND CRANKSHAFT CHECKING THE CRANKSHAFT 1. Measure: • Runout limit "a" • Small end free play limit "b" • Connecting rod big end side clearance "c" • Crank w idth "d" Out of specification → Replace. Use the dial gauge and a thick- ness gauge. CHECKING THE OIL STRAINER 1. Inspect: • Oi ...

  • Yamaha WR450F (2008) - page 158

    5-62 CRANKCASE AND CRANKSHAFT 4. Apply: • Sealant On the right crankc ase. Clean the contacting surface of left and right crankcase before applying the sealant. 5. Install: • Dowel pin "1" • O-ring "2" • Right crankcase To left crankcase. • Apply the lithium soap ba se grease on the O-ring. • Fit the right crankca se ...

  • Yamaha WR450F (2008) - page 159

    5-63 TRANSMISSION, SHIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION, SHIFT CAM AND SHIFT FORK Order Part name Q'ty Remarks Engine Refer to "ENGINE REMOVAL" section. Separate the crankcase. Refer to "CRANKCASE AND CRANK- SHAFT" section. 1 Main axle 1 Refer to remova l section. 2 Drive ...

  • Yamaha WR450F (2008) - page 160

    5-64 TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION 1. Remove: • Main axle "1" • Drive axle "2" • Shift cam • Shift fork 3 • Shift fork 2 • Shift fork 1 • Remove assembly with the collar "3" installed to the crankcase. • Remove assembly carefully. Note the position of each part. Pay pa ...

  • Yamaha WR450F (2008) - page 161

    5-65 TRANSMISSION, SHIFT CAM AND SHIFT FORK • Be sure the circlip sharp-edged cor- ner "a" is po sitioned oppo site side to the washer and gear "b". • Install the circlip with its ends "c" settled evenly on the spline crests. 4. Install: •C o l l a r " 1 " • Apply the lithium soap ba se grease on the ...

  • Yamaha WR450F (2008) - page 162

    6-1 FRONT WHEEL AND REAR WHEEL CHASSIS 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 Front wheel 1 5 Speed sensor 1 6 Co ...

  • Yamaha WR450F (2008) - page 163

    6-2 FRONT WHEEL AND REAR WHEEL REMOVING THE REAR WHEEL Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". 1 Nut (rear wheel axle) 1 2 Rear whe el 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 ...

  • Yamaha WR450F (2008) - page 164

    6-3 FRONT WHEEL AND REAR WHEEL HANDLING NOTE Support the machine securely so there is no dange r of it falling over. REMOVING THE REAR WHEEL 1. Remove: • Wheel "1" Push the wheel forward and remove the drive chain "2". REMOVING THE WHEEL BEARING 1. Remove: • Bearing "1" Remove the bearing using a general bearing pu ...

  • Yamaha WR450F (2008) - page 165

    6-4 FRONT WHEEL AND REAR WHEEL 2. Install: • Brake disc "1" • Bolt (brake disc) "2" Tighten the bolts in stage, using a crisscross pattern. 3. Install: •C o l l a r " 1 " Apply the lithium soap base grease on the oil seal lip. 4. Install: • Speed sensor "1" • Apply the lithium soap ba se grease on t ...

  • Yamaha WR450F (2008) - page 166

    6-5 FRONT WHEEL AND REAR WHEEL 2. Install: • Brake disc "1" • Bolt (brake disc) "2" Tighten the bolts in stage, using a crisscross pattern. 3. Install: • Rear wheel sprocket "1" • Bolt (rear wheel sprocket) "2" • Washer (rear wheel sprocket) "3" • Nut (rear wheel sprocket) "4" ...

  • Yamaha WR450F (2008) - page 167

    6-6 FRONT BRAKE AND REAR BRAKE FRONT BRAKE AND REAR BRAKE REMOVING THE FRONT BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Drain the brake fluid. Refer to removal section. 1 Brake hose hold er (protector) 2 2 Brake hose hold er (brake calipe r) 1 3 Union ...

  • Yamaha WR450F (2008) - page 168

    6-7 FRONT BRAKE AND REAR BRAKE REMOVING THE REAR BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. 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 ...

  • Yamaha WR450F (2008) - page 169

    6-8 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE CALIPER Order Part name Q'ty Remarks A. Front B. Rear AB 1P a d p i n 1 1 2 Brake pad 2 2 3 Pad support 1 1 4 Brake caliper piston 2 1 Re fer to removal section. 5 Brake caliper piston dust s eal 2 1 Refer to removal section. 6 Brake caliper piston seal 2 1 Refer to removal section. ...

  • Yamaha WR450F (2008) - page 170

    6-9 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE MASTER CYLINDER Order Part name Q'ty Remarks A. Front B. Rear 1 Brake master cylinder cap 1 2 Diaphragm 1 3 Reserv oir float 1 4 Brake master cylinder boot 1 5 Circlip 1 Use a long nose circlip pliers. 6 Washer 1 7 Push rod 1 8 Brake master cylinder kit 1 ...

  • Yamaha WR450F (2008) - page 171

    6-10 FRONT BRAKE AND REAR BRAKE HANDLING NOTE Support the machine securely so there is no dange r of it falling over. DRAINING THE BRAKE FLUID 1. Remove: • Brake master cylinder cap "1" • Protector (rear brake) Do not remove the diaphragm. A. Front B. Rear 2. Connect the transparent hose " 2" to the bleed screw "1" ...

  • Yamaha WR450F (2008) - page 172

    6-11 FRONT BRAKE AND REAR BRAKE 4. Inspect: • Brake master cylinder piston "1" • Brake master cylinder cup "2" Wear/damage/score marks → Re- place brake master cylinder kit. A. Front B. Rear CHECKING THE BRAKE CALIPER 1. Inspect: • Brake caliper cylinder inner sur- face "a" Wear/score marks → Replace brake ca ...

  • Yamaha WR450F (2008) - page 173

    6-12 FRONT BRAKE AND REAR BRAKE 4. Install: • Pad pin plug "4" INSTALLING THE REAR BRAKE CALIPER 1. Install: • Pad support "1" • Brake pad "2" • Pad pin "3" • Install the brake pads with th eir pro- jections "a" into the brake caliper re - cesses "b". • Tempora rily tighten the ...

  • Yamaha WR450F (2008) - page 174

    6-13 FRONT BRAKE AND REAR BRAKE 2. Install: • Brake lever "1" • Bolt (brake lever) "2" • Nut (brake lever) "3" Apply the silicone grease on the brake lever sliding surface, bolt an d contacting surface of the brake mas- ter cylinder piston. INSTALLING THE REAR BRAKE MASTER CYLINDER 1. Install: • Copper washer & ...

  • Yamaha WR450F (2008) - page 175

    6-14 FRONT BRAKE AND REAR BRAKE 3. Install: • Brake hose hol der "1" • Nut (brake h ose holder) "2" Align the top "a" of the brake hose holder with the paint "b" of the brake hose. 4. Pass the brake hose through the front brake hose guides "1". 5. Install: • Copper washer "1" • Bra ...

  • Yamaha WR450F (2008) - page 176

    6-15 FRONT BRAKE AND REAR BRAKE 3. Inspect: • Brake fluid level Fluid at lower l evel → Fill up. Refer to "CHECKING THE BRAKE FLUID LEVEL" section in the CHAPTER 3. 4. Install: • Reservoir float (front brake) • Diaphragm • Brake master cylinder cap "1" • Screw (bolt) {brake master cylin- der cap} "2" After ...

  • Yamaha WR450F (2008) - page 177

    6-16 FRONT FORK FRONT FORK REMOVING THE FRONT FORK Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Front wheel Refer to "FRONT WHEEL AND REAR WHEEL" section. Front brake caliper Refer to "FRONT BRAKE AND REAR BRAKE" section. Headlight Handleba ...

  • Yamaha WR450F (2008) - page 178

    6-17 FRONT FORK DISASSEMBLING THE F RONT FORK Order Part name Q'ty Remarks 1 Front fork cap bolt 1 Refer to removal section. 2 Fork spring 1 Drain the fork oil. 3 Dust seal 1 Refer to removal sectio n. 4 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 ...

  • Yamaha WR450F (2008) - page 179

    6-18 FRONT FORK HANDLING NOTE Support the machine securely so there is no dange r of it falling over. The front fork requires careful atten- tion. So it is recommended that the front fork be maintained at the deal- ers. To prevent an ac cidental explosion of air, the following instructions should be observed: • The front fork with a built- in pis ...

  • Yamaha WR450F (2008) - page 180

    6-19 FRONT FORK The bending value is shown by one half of the dial gauge reading. Do not attempt to straighten a bent inner tube as this may dangerous- ly weaken the tube . CHECKING THE OUTER TUBE 1. Inspect: • Outer tub e "1" Score marks/we ar/damage → Re- place. CHECKING THE FRONT FORK CAP BOLT 1. Inspect: • Front fork cap bolt &q ...

  • Yamaha WR450F (2008) - page 181

    6-20 FRONT FORK 8. Install: • Outer tub e "1" To inner tube "2". 9. Install: • Slide metal " 1" • Oil seal washer "2" To outer tube slot. Press the slide metal into the outer tube with fork seal driver "3". 10. Install: • Oil seal "1" Press the oil seal into the outer tube with for ...

  • Yamaha WR450F (2008) - page 182

    6-21 FRONT FORK Be sure to install the spring guide "2" when checking the oil level. Never fail to make the oil level ad- justment between the maximum and minimum level and always ad - just each front fork to the same setting. Uneven adjustmen t can cause poor h andling and loss of stability. 21. Measure: • Distance "a" Out of ...

  • Yamaha WR450F (2008) - page 183

    6-22 FRONT FORK 3. Adjust: • Front fork top end "a" 4. Tighten: • Pinch bolt (upper bracket) "1" • Pinch bolt (lower bracket) "2" Tighten the lower brac ket to speci- fied torque. If to rqued too much, it may cause the fron t fork to mal- function. 5. Install: • Speed sensor lead "1" • Plate 1 " ...

  • Yamaha WR450F (2008) - page 184

    6-23 HANDLEBAR HANDLEBAR REMOVING THE HANDLEBAR Order Part name Q'ty Remarks Headlight 1 Hot starter cable 1 Disconnect at the lever side. 2 Hot start er lever holder 1 3 Clutch cable 1 Disconnect at the lever side. 4 Clutch lever holder 1 Disconnect the clutch switch lead. 5 Engine stop switch 1 Disconnect the engine stop switch lead. 6 Brake ...

  • Yamaha WR450F (2008) - page 185

    6-24 HANDLEBAR REMOVING THE BRAKE MASTER CYLINDER 1. Remove: • Brake master cylinder bracket "1" • Brake master cylinder "2" • Do not let the brake master cylin- der hang on th e brake hose. • Keep the brake master cylin der cap side horizontal to prevent air from coming in. REMOVING THE GRIP 1. Remove: •G r i p " ...

  • Yamaha WR450F (2008) - page 186

    6-25 HANDLEBAR 5. Install: • Right grip "1" •C o l l a r " 2 " Apply the adhesive o n the tube guide "3". • Before applying the adhesive, wipe off grease or oil on the tube guide surface "a" with a lacquer thinner. • Install the grip to the tube guide so that the grip match mark "b" and tube ...

  • Yamaha WR450F (2008) - page 187

    6-26 HANDLEBAR 12. Install: • Clutch cable "1" • Hot starter cable "2" Apply the lithium soap base grease on the clutch cable end and hot start- er cable end. 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 &qu ...

  • Yamaha WR450F (2008) - page 188

    6-27 STEERING STEERING REMOVING THE STEERING Order Part name Q'ty Remarks TIGHTENING STEPS: • Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb) • Loosen it one turn. • Retighten it. 7 Nm (0.7 m•kg, 5.1 ft• lb) Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Headlight Handlebar Refer ...

  • Yamaha WR450F (2008) - page 189

    6-28 STEERING 9 Bearing race cover 1 10 Upper bearing 1 11 Lower bearing 1 Refer to removal section. 12 Bearing race 2 Refer to removal sectio n. Order Part name Q'ty Remarks ...

  • Yamaha WR450F (2008) - page 190

    6-29 STEERING HANDLING NOTE Support the machine securely so there is no dange r of it falling over. REMOVING THE STEERING RING NUT 1. Remove: • Steering ring nut "1" Use the steering nut wrench "2". Support the steering stem so that it may not fall d own. REMOVING THE LOWER BEARING 1. Remove: • Lower bearing "1" Us ...

  • Yamaha WR450F (2008) - page 191

    6-30 STEERING 6. Install: • Washer "1" 7. Install: • Front fork "1" • Upper bracket "2" • Main switch "3" • Front brake hose guide bracket "4" • Temporarily tighten the p inch bolts (lower brack et). • Do not tighten the pinch bolts (up- per bracket) yet. 8. Install: • Guide (speed s ...

  • Yamaha WR450F (2008) - page 192

    6-31 SWINGARM SWINGARM REMOVING THE SWINGARM Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING 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) ...

  • Yamaha WR450F (2008) - page 193

    6-32 SWINGARM DISASSEMBLING 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 remova l section. ...

  • Yamaha WR450F (2008) - page 194

    6-33 SWINGARM HANDLING NOTE Support the machine securely so there is no dange r of it falling over. REMOVING THE CAP 1. Remove: • Left cap "1" Remove with a slotted-head screw- driver inserted under the mark " a" on the left cap. REMOVING THE BEARING 1. Remove: • Bearing "1" Remove the bearing by pressing its outer ...

  • Yamaha WR450F (2008) - page 195

    6-34 SWINGARM INSTALLING THE SWINGARM 1. Install: • Bushing "1" • Thrust bearing "2" • Oil seal "3" •C o l l a r " 4 " To swingarm "5" Apply the molybdenum disulfide grease on the bushin gs, thrust bear- ings, oil seal lips and contact surfaces of the collar and thrust b earing. 2. Install: ...

  • Yamaha WR450F (2008) - page 196

    6-35 SWINGARM 10. Tighten: • Nut (connecting rod) "1" 11. Tighten: • Nut (relay arm) "1" 12. Install: •C a p " 1 " Install the right cap with its mark "a" facing forward. 13. Install: • Bolt (lower chain tensioner) "1" • Washer "2" •C o l l a r " 3 " • Lower chain t ...

  • Yamaha WR450F (2008) - page 197

    6-36 REAR SHOCK ABSORBER REAR SHOCK ABSORBER REMOVING THE REAR SHOCK ABSORBER Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Seat and side cover Refer to "REMOVING THE SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 3. Silencer Refer to "R ...

  • Yamaha WR450F (2008) - page 198

    6-37 REAR SHOCK ABSORBER 1 Locking tie 4 2 Taillight coupler 1 3 CDI unit coupler 3 4 Plastic band 1 5 Clamp (air filter joint) 1 Only loosening. 6R e a r f r a m e 1 7 Bolt (rear shock absorber-relay arm) 1 Hold the swingarm. 8 Bolt (rear shock absorber-frame) 1 9 Rear shock absorber 1 10 Locknut 1 Only l oosening. 11 Adjuster 1 Only loosen ing. 1 ...

  • Yamaha WR450F (2008) - page 199

    6-38 REAR SHOCK ABSORBER HANDLING NOTE • Support the machin e securely so there is no danger of it falling over. • This rear s hock absorber is pro- vided with a separate type tank filled with high- pressure nitro- gen gas. To pr event the danger of explosion, read and u nder- stand the follow ing information before handli ng the shock ab- sorb ...

  • Yamaha WR450F (2008) - page 200

    6-39 REAR SHOCK ABSORBER 3. Install: • Lower bearing "1" Install the bearing by pressing it on the side having the manufacture' s marks or numbers. INSTALLING THE SPRING (REAR SHOCK ABSORBER) 1. Install: • Spring "1" • Upper spring guide "2" • Lower spring guide "3" 2. Tighten: •A d j u s t e r ...

  • Yamaha WR450F (2008) - page 201

    6-40 REAR SHOCK ABSORBER 7. Tighten: • Screw (air filter joint) "1" 8. Install: • Plastic band • Taillight coupler • Locking tie Screw (air filter joint): 3 Nm (0.3 m•kg, 2.2 ft•lb) ...

  • Yamaha WR450F (2008) - page 202

    7-1 ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS 1. Headlight 2. Multi-function displ ay 3. Engine stop switch 4. Clutch switch 5. Diode 6. Starter relay diode 7. Throttle position sensor 8. Starter relay 9. Fuse 10. Starting circuit cut-off relay 11. CDI unit 12. Taillight 13. N ...

  • Yamaha WR450F (2008) - page 203

    7-2 ELECTRICAL COMPONENTS AND WIRING DIAGRAM WIRING DIAGRAM 1. Headlight 2. Multi-function displ ay 3. Engine stop switch 4. Clutch switch 5. Diode 6. Starter relay diode 7. Throttle position sensor 8. Starter relay 9. Fuse 10. Starting circuit cut-off relay 11. CDI unit 12. Taillight 13. Neutral switch 14. Starter motor 15. AC magneto 16. Re ctifi ...

  • Yamaha WR450F (2008) - page 204

    7-3 IGNITION SYSTEM IGNITION SYSTEM INSPECTION STEPS Use the following steps for checking the possibility of the malfuncti oning engine being attributable to igni tion system failure and for checking the spa rk plug which will not spark. *1 marked: Refer to "CHECKING TH E FUSE" section in the CHAPTER 3. *2 marked: Refer to "CHECKING ...

  • Yamaha WR450F (2008) - page 205

    7-4 IGNITION SYSTEM SPARK GAP TEST 1. Disconnect the ignition coil from spark plug. 2. Remove the ignition co il cap. 3. Connect the dynamic spark tester "1" (ignition ch ecker "2") as shown. • Ignition coil "3" • Spark plug "4" A. For USA and CDN B. Except for USA and CDN 4. Kick the kickstarter crank. 5 ...

  • Yamaha WR450F (2008) - page 206

    7-5 ELECTRIC STARTING SYSTEM 4. Inspect: • Sealed portion of ignition coil "a" • Spark plug terminal pin "b" • Threaded portion of sp ark plug "c" Wear → Replace. CHECKING THE AC MAGNETO 1. Inspect: • Pickup coil resistance Out of specification → Replace. CHECKING THE NEUTRAL SWITCH 1. Inspect: • Neutral ...

  • Yamaha WR450F (2008) - page 207

    7-6 ELECTRIC STARTING SYSTEM INSPECTION STEPS If the starter motor will not operate, use the fo llowing inspection steps. *1 marked: Refer to "CHECKING TH E FUSE" section in the CHAPTER 3. *2 marked: Refer to "CHECKING AND CHARGIN G THE BATTERY" section in the CHAPTER 3. *3 marked: Refer to "CHECKING THE MAIN SWITCH" s ...

  • Yamaha WR450F (2008) - page 208

    7-7 ELECTRIC STARTING SYSTEM CHECKING THE COUPLERS AND LEADS CONNECTION 1. Check: • Couplers and leads con nection Rust/dust/looseness/short-circuit → Repai r or replace. CHECKING THE STARTER MOTOR OPERATION 1. Connect the posi tive battery ter- minal "1" and starter motor lead "2" with a jumper lead " 3". Not oper ...

  • Yamaha WR450F (2008) - page 209

    7-8 ELECTRIC STARTING SYSTEM 2. Inspect: • Rubber part "a" Tears/damage → Replace. ...

  • Yamaha WR450F (2008) - page 210

    7-9 ELECTRIC STARTING SYSTEM REMOVING THE STARTER MOTOR Order Part name Q'ty Remarks Exhaust pipe Refer to "REMOVING THE EXHAUST PIPE AND SILENCER" section in the CHAPTER 3. 1 Starter motor 1 ...

  • Yamaha WR450F (2008) - page 211

    7-10 ELECTRIC STARTING SYSTEM DISASSEMBLING THE STARTER MOTOR Order Part name Q'ty Remarks 1 Starter motor front cover 1 2 Washer (starter motor front cover) 1 3 Washer 1 4 Circlip 1 5O - r i n g 1 6 Starter motor yoke 1 7 Armature assembly 1 8 Starter motor rear cover 1 9 Brush 2 10 Brush spring 2 ...

  • Yamaha WR450F (2008) - page 212

    7-11 ELECTRIC STARTING SYSTEM CHECKING AND REPAIRING THE STARTER MOTOR 1. Check: • Commutator Dirt → Clean with 600 grit san dpa- per. 2. Measure: • Commutator diameter "a" Out of specification → Replace the starter motor. 3. Measure: • Mica undercut "a" Out of specification → Scrape the mica to the prope r measureme ...

  • Yamaha WR450F (2008) - page 213

    7-12 ELECTRIC STARTING SYSTEM • For installation, align the proj ec- tions on the washer with the slots in the front cover. • Align the match mark "a" on the starter motor yoke with the match mark "b" on the starter motor front cover. 5. Install: •B o l t " 1 " • O-ring "2" Apply the lithium soap base ...

  • Yamaha WR450F (2008) - page 214

    7-13 CHARGING SYSTEM CHARGING SYSTEM INSPECTION STEPS If the battery is not charged, use the followin g inspection steps. *1 marked: Refer to "CHECKING TH E FUSE" section in the CHAPTER 3. *2 marked: Refer to "CHECKING AND CHARGIN G THE BATTERY" section in the CHAPTER 3. • Remove the following p arts before i nspection. 1. Sea ...

  • Yamaha WR450F (2008) - page 215

    7-14 CHARGING SYSTEM CHECKING THE COUPLERS AND LEADS CONNECTION 1. Check: • Couplers and leads con nection Rust/dust/looseness/short-circuit → Repai r or replace. CHECKING THE CHARGING VOLTAGE 1. Start the engine. 2. Inspect: • Chargin g voltage Out of specification → If no failure is found in checking the source coil resistance, replace th ...

  • Yamaha WR450F (2008) - page 216

    7-15 THROTTLE POSITION SENSOR SYSTEM THROTTLE POSITION SENSOR SYSTEM INSPECTION STEPS If the throttle position senso r will not operate, use the follo wing inspection steps. Use the following special to ols in this inspection. Check entire ignition system for connection. No good → Repai r or replace. OK ↓ Check throttle position sen sor.(Thrott ...

  • Yamaha WR450F (2008) - page 217

    7-16 THROTTLE POSITION SENSOR SYSTEM HANDLING NOTE Do not loosen th e screw (throttle position sensor) "1" except when changing the th rottle position sen- sor due to failur e because it will cause a drop in engine pe rfor- mance. CHECKING THE COUPLERS AND LEADS CONNECTION 1. Check: • Couplers and leads con nection Rust/dust/looseness/s ...

  • Yamaha WR450F (2008) - page 218

    7-17 THROTTLE POSITION SENSOR SYSTEM Measure the output voltage accurate- ly with a digital e lectronic voltmeter that gives an easy reading of a small voltage. 10. Put the aligning marks "a" on the throttle position sensor and car- buretor. 11. Stop the engine. 12. Remove the carburetor. 13. Tighten: • Screw (throttle position sensor) ...

  • Yamaha WR450F (2008) - page 219

    7-18 LIGHTING SYSTEM LIGHTING SYSTEM INSPECTION STEPS Refer to th e following flow chart when inspect ing the lighting system for possible problems. • Remove the following p arts before i nspection. 1. Seat 2. Fuel tank 3. Left side cover • Use the following special to ols in this inspection. Check the bulb and bulb socket. No goo d → Rep lac ...

  • Yamaha WR450F (2008) - page 220

    7-19 LIGHTING SYSTEM CHECKING THE TAILLIGHT (LEDs) 1. Disconnect the taillight coupler. 2. Connect two jumper leads "1" from the battery terminals to the respective coupler terminal as shown. 3. Check: • LED (for proper operation) Does not light → Replace the tail - light assemb ly. • A wire that is used as a jumper lead must have a ...

  • Yamaha WR450F (2008) - page 221

    7-20 SIGNALING SYSTEM SIGNALING SYSTEM INSPECTION STEPS If the speedometer will not operate , use the following inspection steps. *1 marked: Refer to "CHECKING AND CHARGIN G THE BATTERY" section in the CHAPTER 3. • Remove the following p arts before i nspection. 1. Headlight • Use the following special to ols in this inspection. *1 Ch ...

  • Yamaha WR450F (2008) - page 222

    7-21 SIGNALING SYSTEM CHECKING THE COUPLERS AND LEADS CONNECTION 1. Check: • Couplers and leads con nection Rust/dust/looseness/short-circuit → Repai r or replace. CHECKING THE MULTI-FUNCTION DISPLAY INPUT VOLTAGE 1. Disconne ct the multi-function dis- play coupler. 2. Set the main switch to "ON". 3. Measure: • Multi-function displa ...

Manufacturer Yamaha Category Motorcycle

Documents that we receive from a manufacturer of a Yamaha WR450F (2008) can be divided into several groups. They are, among others:
- Yamaha technical drawings
- WR450F (2008) manuals
- Yamaha product data sheets
- information booklets
- or energy labels Yamaha WR450F (2008)
All of them are important, but the most important information from the point of view of use of the device are in the user manual Yamaha WR450F (2008).

A group of documents referred to as user manuals is also divided into more specific types, such as: Installation manuals Yamaha WR450F (2008), service manual, brief instructions and user manuals Yamaha WR450F (2008). Depending on your needs, you should look for the document you need. In our website you can view the most popular manual of the product Yamaha WR450F (2008).

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A complete manual for the device Yamaha WR450F (2008), how should it look like?
A manual, also referred to as a user manual, or simply "instructions" is a technical document designed to assist in the use Yamaha WR450F (2008) by users. Manuals are usually written by a technical writer, but in a language understandable to all users of Yamaha WR450F (2008).

A complete Yamaha manual, should contain several basic components. Some of them are less important, such as: cover / title page or copyright page. However, the remaining part should provide us with information that is important from the point of view of the user.

1. Preface and tips on how to use the manual Yamaha WR450F (2008) - At the beginning of each manual we should find clues about how to use the guidelines. It should include information about the location of the Contents of the Yamaha WR450F (2008), FAQ or common problems, i.e. places that are most often searched by users in each manual
2. Contents - index of all tips concerning the Yamaha WR450F (2008), that we can find in the current document
3. Tips how to use the basic functions of the device Yamaha WR450F (2008) - which should help us in our first steps of using Yamaha WR450F (2008)
4. Troubleshooting - systematic sequence of activities that will help us diagnose and subsequently solve the most important problems with Yamaha WR450F (2008)
5. FAQ - Frequently Asked Questions
6. Contact detailsInformation about where to look for contact to the manufacturer/service of Yamaha WR450F (2008) in a specific country, if it was not possible to solve the problem on our own.

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