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Manual Yamaha YZ450FA

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  • Yamaha YZ450FA - page 1

    PRINTED IN JAP AN 2010.05—0.8 × 1 ! (E) Y AMAHA MO T OR CO . , L TD . 2500 SHINGAI IW A T A SHIZUOKA JAP AN PRINTED ON RECYCLED P APER PROTECT YOUR INVESTMENT Use Genuine YAMAHA Parts And Accessories YZ 450F A 2011 O WNER’S SER VICE MANU AL YZ 450F A 33D-28199-11 LIT -11626-24-22 2011 q Read this manual carefull y before operating this vehic l ...

  • Yamaha YZ450FA - page 2

    Q Read this manual carefull y before operating this vehicle. This manual should sta y with this vehicle if it is sold. 33D-9-10_cover 09.7.16 13:11 ページ 2 ...

  • Yamaha YZ450FA - page 3

    YZ450FA OWNER'S SERVICE MANUAL ©2010 by Yamaha Motor Corporation, U.S.A. 1st Edition, May 2010 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Corporation, U.S.A. is expressly prohibited. Printed in Japan P/N. LIT-11626-24-22 ...

  • Yamaha YZ450FA - page 4

    INTRODUCTION Congratulations on your purchase of a Yamaha YZ series. This model is the culmination of Ya- maha's vast experience in the p roduction of pacesetting racing machines. It repre sents the highest grade of craftsmansh ip and reliability that have made Yamaha a leader. This manual explains o peration, inspection, ba- sic maintenance a ...

  • Yamaha YZ450FA - page 5

    SAFETY INFORMATION THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED COURSE. It is illegal for this machin e to be operated on any public street, road, or highway. Off-road use on public lands may also be illegal. Please check local regulations be- fore riding. • THIS MACHINE IS TO BE OPERATED BY AN EXPERIENCED RIDER ONLY. D ...

  • Yamaha YZ450FA - page 6

    YAMAHA MOTOR CORPORATION, U.S.A. YZ MOTORCYCLE LIMITED WARRANTY ...

  • Yamaha YZ450FA - page 7

    HOW TO USE THIS MANUAL FINDING THE REQUIRED PAGE 1. This manual consists of eight cha pters; "General Information", "Specifications", "Regular inspec- tion and adjustments", "Engine", "Cha ssis", "Fuel system", "Electrical" and "Tuning". 2. The table of contents is at t ...

  • Yamaha YZ450FA - page 8

    HOW TO READ DESCRIPTIONS To help identify parts and clarify procedure step s, there are exploded diagrams at the start of each removal and disassembly section. 1. An easy-to-see exploded diagram "1" is pr ovided for removal and disassembly job s. 2. Numbers "2" are given in the order of the jobs in the exploded diagram. A number ...

  • Yamaha YZ450FA - page 9

    ILLUSTRATED SY MBOLS (Refer to the illustration) Illustrated symbols "1" to "7" are used to iden ti- fy the specifications appearin g 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), Elect ric cur- rent (A) Illustr ...

  • Yamaha YZ450FA - page 10

    MEMO ...

  • Yamaha YZ450FA - page 11

    TABLE OF CONTENTS GENERAL INFORMATION 1 SPECIFICATIONS 2 REGULAR INSPECTION AND ADJUSTMENTS 3 ENGINE 4 CHASSIS 5 FUEL SYSTEM 6 ELECTRICAL 7 TUNING 8 ...

  • Yamaha YZ450FA - page 12

    CONTENTS CHAPTER 1 GENERAL INFORMATION LOCATION OF IMPORTANT LABELS ..... 1-1 DESCRIPTION ........................................... 1-2 CONSUMER INFORMATION .................... 1-3 FEATURES ............................................... . 1-4 INCLUDED PARTS .................................... 1-6 IMPORTANT INFORMATION .................... 1-8 ...

  • Yamaha YZ450FA - page 13

    CHAPTER 3 REGULAR INSPECTION AND ADJUSTMENTS MAINTENANCE INTERVALS .................... 3-1 PRE-OPERATION INSPECTION AND MAINTENANCE ......................................... 3-6 ENGINE ...................................................... 3-7 CHASSIS .................................................. 3-20 ELECTRICAL .............................. ...

  • Yamaha YZ450FA - page 14

    CHAPTER 5 CHASSIS FRONT WHEEL AND REAR WHEEL ....... 5-2 FRONT BRAKE AND REAR BRAKE ........ 5-9 FRONT FORK ................................. ......... 5-23 HANDLEBAR ........................................... 5-36 STEERING ............................................... 5-42 SWINGARM ............................................. 5-47 REAR SHOCK A ...

  • Yamaha YZ450FA - page 15

    1-1 LOCATION OF IMPORTANT LABELS GENERAL INFORMATION LOCATION OF IMPORTANT LABELS Please read the following important la bels ca refully before operating this vehicle. Premium unleaded gasoline only. 3FB-2415E-02 4AA-22259-80 WARNING This unit contains high pressure nitrogen gas. Mishandling can cause explosion. Read owner’s manual for instructio ...

  • Yamaha YZ450FA - page 16

    1-2 DESCRIPTION DESCRIPTION • The machine you have purchased may differ sl ight ly from those shown in the following. • Designs and specifications ar e subject to change without notice. 1. Clutch lever 2. Front brake lever 3. Throttle grip 4. Radiator cap 5. Fuel tank cap 6. Engine stop switch 7. Kickstarter crank 8. Fuel tank 9. Radiator 10. C ...

  • Yamaha YZ450FA - page 17

    1-3 CONSUMER INFORMATION CONSUMER INFORMATION There are two significant reasons for knowing the serial number of your machine: 1. When ordering parts, you can give the num- ber to your Yamaha dealer for posit ive iden- tification of the model you own. 2. If your machine is stolen, the authorit ies will need the number to search for and identify you ...

  • Yamaha YZ450FA - page 18

    1-4 FEATURES FEATURES OUTLINE OF THE FI SYSTEM The main function of a fuel supply system is to pr ovide fuel to the combustion ch amber at the opti- mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera- ture.Inthe conventional carburetor system, th e air-fuel ratio of the mixture that is sup plied to the ...

  • Yamaha YZ450FA - page 19

    1-5 FEATURES FI SYSTEM The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regu lator maintains the fuel pressure that is applied t o the fuel injector at only 324 kPa (3.24 kgf/cm ² , 47.0 psi). According- ly,when the energizing signal from the ECU energizes th e fuel injector, the fuel passage opens, caus- ing the ...

  • Yamaha YZ450FA - page 20

    1-6 INCLUDED PARTS INCLUDED PARTS DETACHABLE SIDESTAND This sidestand "1" is used to support only the machine when standing or transporting it. • Never apply additional force to the side- stand. • Remove this sidestand before starting out. VALVE JOINT This valve joint "1" prevents fuel from flowing out and is installed to th ...

  • Yamaha YZ450FA - page 21

    1-7 INCLUDED PARTS FUEL HOSE JOINT COVER The fuel hose joint covers "1" are u sed to pre- vent mud, dust, and other foreign materia l from entering the fuel pump when the fuel hose is disconnected. COUPLER FOR CONNECTING OPTIONAL PART This coupler "1" is used for connection to an op- tional Power Tuner and so on. When no optiona ...

  • Yamaha YZ450FA - page 22

    1-8 IMPORTANT INFORMATION IMPORTANT INFORMATION PREPARATION FOR REMOVAL AND DISASSEMBLY 1. Remove all dirt, mud, dust, and foreign ma- terial before removal and disassembly. • When washing the machine with high pres- sured water, cover the parts follows. Air duct Silencer exhaust port Drain hole on the cylinder head ( right side) Water pump housi ...

  • Yamaha YZ450FA - page 23

    1-9 IMPORTANT INFORMATION LOCK WASHERS/PLATES AND COTTER PINS 1. All lock washers/plates "1" and cotter pins must be replaced when they are removed. Lock tab(s) should be bent along the bolt or nut flat(s) after the bolt or nut has been prop- erly tightened. BEARINGS AND OIL SEALS 1. Install the bearing(s) "1" and oil se al(s) & ...

  • Yamaha YZ450FA - page 24

    1-10 HANDLING THE ELECTRONIC PARTS HANDLING THE ELECTRONIC PARTS Electronic parts are very sensitive. Handle with care and do not give impact. • Mankind has static electricity . It`s voltage is very high and electronic parts are v ery sensitive. • It is possible that inner small components of electronic parts are destroyed by sta tic electricit ...

  • Yamaha YZ450FA - page 25

    1-11 CHECKING OF CONNECTION 5. Check: •C o n t i n u i t y (with the pocket tester) • If there is no continui ty, clean the terminals. • When checking the wire harness, perform steps (1) to (5). • As a quick remedy, use a contact revitalizer available at most part store s. When you check the voltage or electrical co nti- nuity, insert the m ...

  • Yamaha YZ450FA - page 26

    1-12 SPECIAL TOOLS SPECIAL TOOLS The proper special tools are necessary for complete and accurate tune-u p and assembly. Using the correct special tool will help prevent damage caused by the use of im proper tools or improvised tech- niques. The shape and part number u sed for the special tool differ by country, so two types are pro- vided. Refer t ...

  • Yamaha YZ450FA - page 27

    1-13 SPECIAL TOOLS Steering nut wrench YU-33975, 90890-01403 This tool is used when tigh ten the steering ring nut to speci- fication. Cap bolt wrench YM-01500, 90890-01500 This tool is used to loosen or tighten the base valve. Cap bolt ring wrench YM-01501, 90890-01501 This tool is used to loosen or tighten the damper assembly. Fork seal driver YM ...

  • Yamaha YZ450FA - page 28

    1-14 SPECIAL TOOLS Pressure gauge. YU-03153, 90890-03153 This tool is used to me asure the fuel pressure. FI diagnostic tool YU-03182, 90890-03182 This tool is used to check the fault codes and diagnose any problems. Fuel pressure adapter YM-03186, 90890-03186 This tool is used to attach the pressure gauge. Test harness S-pressure sen- sor (3P) YU- ...

  • Yamaha YZ450FA - page 29

    1-15 SPECIAL TOOLS Clutch holding tool YM-91042, 90890-04086 This tool is used to hold the clutch when removing or in- stalling the clutch boss secur- ing nut. Valve guide remover 5.5 mm (0.22 in) YM-01122 This tool is needed to remove and install the valve guide . Valve guide installer 5.5 mm (0.22 in) YM-04015 This tool is needed to in stall the ...

  • Yamaha YZ450FA - page 30

    1-16 SPECIAL TOOLS Dynamic spark tester YM-34487 Ignition checker 90890-06754 This instrument is necessary for checking the ignitio n sys- tem components. Digital tachometer YU-39951-B, 90890-06760 This tool is needed for ob- serving engine rpm. YAMAHA Bond No. 1215 (ThreeBond ® No. 1215) 90890-85505 This sealant (Bond) is used for crankcase matin ...

  • Yamaha YZ450FA - page 31

    1-17 CONTROL FUNCTIONS CONTROL FUNCTIONS ENGINE STOP SWITCH The engine stop switch "1" is located on the left handlebar. Continue pushing the e ngine stop switch till the engine comes to a stop. CLUTCH LEVER The clutch lever "1" is located on the left h an- dlebar; it disengages or engages th e clutch. Pull the clutch lever to t ...

  • Yamaha YZ450FA - page 32

    1-18 CONTROL FUNCTIONS 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. STARTER KNOB/IDLE SCREW The starter knob/idle screw "1" is used when starting a cold engine. Pull the starter knob/idle screw out to open the circuit for startin ...

  • Yamaha YZ450FA - page 33

    1-19 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 gasoline. The use o f leaded gasoline will cause severe dama ge to the engine internal parts such a s valves, piston rings, and exhaust syste m, etc. Your Yamaha engine has bee ...

  • Yamaha YZ450FA - page 34

    1-20 STARTING AND BREAK-IN 6. When the engine starts running, warm it up one or two minutes at a steady speed (of 3,000 to 5,000 r/min), and then return the starter knob/ idle screw to its original posi- tion. 7. Push the engine stop switch "1". Do not warm up the engine for extended pe- riods of time. STARTING A WARM ENGINE To start a wa ...

  • Yamaha YZ450FA - page 35

    1-21 TORQUE-CHECK POINTS TORQUE-CHECK POINTS Concerning the tightening torque, refer to "T IGHTENING 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 YZ450FA - page 36

    1-22 CLEANING AND STORAGE CLEANING AND STORAGE CLEANING Frequent cleaning of your machin e will en- hance its appearance, maintain good o verall performance, and extend the life of many com- ponents. 1. Before washing the machine, block off the end of the exhaust pipe to prevent water from entering. A plastic bag secured with a rubber band may be u ...

  • Yamaha YZ450FA - page 37

    2-1 GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model name: YZ450FA (USA, CDN, AUS) YZ450F (EUROPE, NZ, ZA) Model code number: 33D5 (USA,CDN) 33D6 (EUROPE) 33D8 (AUS, NZ, ZA) Dimensions: USA, CDN EUROPE AUS, NZ, ZA Overall length 2,193 mm (86.34 in) 2,191 mm (86.26 in) 2,194 mm (86.38 in) Overall width 825 mm (32.48 in) ←← Over ...

  • Yamaha YZ450FA - page 38

    2-2 GENERAL SPECIFICATIONS 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 (including all routes): 1.13 L (0.99 Imp qt, 1.19 US qt) Air filter: Wet type element Fuel: Type Premium unleaded gasoline ...

  • Yamaha YZ450FA - page 39

    2-3 GENERAL SPECIFICATIONS Chassis: USA, CDN EUROPE AUS, NZ, ZA Frame type Semi double cradle ←← Caster angle 26.9° 26.8° 26.9° Trail 118.6 mm (4.67 in) 117.5 mm (4.63 in) 119.0 mm (4.69 in) Tire: Type With tube Size (front) 80/100-21 51M Size (rear) 120/80-19 63M (For USA, CDN, AUS, NZ, ZA) 110/90-19 62M (For EUROPE) Tire pressure (front an ...

  • Yamaha YZ450FA - page 40

    2-4 MAINTENANCE SPECIFICATIONS MAINTENANCE SPECIFICATIONS ENGINE Item Standard Limit Cylinder head: Warp limit ---- 0.05 mm (0.002 in) Cylinder: Bore size 97.00–97.01 mm (3.8189–3.8193 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 (0.8661–0.86 ...

  • Yamaha YZ450FA - page 41

    2-5 MAINTENANCE SPECIFICATIONS Camshaft runout limit ---- 0.03 mm (0.0012 in) Timing chain: Timing chain type/No. of links 98XRH2010-122M/122 ---- Timing chain adjustme nt method Automatic ---- 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 dimens ...

  • Yamaha YZ450FA - page 42

    2-6 MAINTENANCE SPECIFICATIONS "D" margin thickness (IN) 1.3 mm (0.0512 in) ---- "D" margin thickness (EX) 1.0 mm (0.0394 in) ---- Stem outside diameter (IN) 5.475–5.490 mm (0.2156–0.2161 in) 5.445 mm (0.2144 in) Stem outside diameter (EX) 5.465–5.480 mm (0.2152–0.2157 in) 5.435 mm (0.2140 in) Guide inside diameter (IN) ...

  • Yamaha YZ450FA - page 43

    2-7 MAINTENANCE SPECIFICATIONS Tilt limit* (IN) ---- 2.5°/1.8 mm (2.5°/0.071 in) Tilt limit* (EX) ---- 2.5°/1.6 mm (2.5°/0.063 in) Direction of winding (top view) (IN) Clockwise ---- Direction of winding (top view) (EX) Clockwise ---- Piston: Piston to cylinder clearance 0.020–0.045 mm (0.0008–0.0018 in) 0.1 mm (0.004 in) Piston size " ...

  • Yamaha YZ450FA - page 44

    2-8 MAINTENANCE SPECIFICATIONS 2nd ring: Type Taper ---- Dimensions (B × T) 1.00 × 3.10 mm (0.04 × 0.12 in) ---- End gap (installed) 0.35–0 .50 mm (0.014–0.020 in) 0.85 mm (0.033 in) Side clearance 0.020–0.060 mm (0.0008–0.0024 in) 0.120 mm (0.0047 in) Oil ring: Dimensions (B × T) 1.5 × 2.55 mm (0.06 × 0.10 in) ---- End gap (installed ...

  • Yamaha YZ450FA - page 45

    2-9 MAINTENANCE SPECIFICATIONS Clutch spring free length 50.0 mm (1.97 in) 49.0 mm (1.93 in) Quantity 6 ---- Clutch housing thrust clearanc e 0.10–0.35 mm (0.0039–0.0138 in) ---- Clutch housing radial cle arance 0.010–0.044 mm (0.0004–0.0017 in) ---- Clutch release method Inner push, cam push ---- Shifter: Shifter type Cam drum and guide ba ...

  • Yamaha YZ450FA - page 46

    2-10 MAINTENANCE SPECIFICATIONS CHASSIS 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) 0.17 mm (0.007 in) Byp ...

  • Yamaha YZ450FA - page 47

    2-11 MAINTENANCE SPECIFICATIONS Rear suspension: USA, CDN EUROPE, AUS, NZ, ZA Shock absorber travel 13 2.0 mm (5.20 in) ← ---- Spring free length 260 mm (10.24 in) ← 254.8 mm (10.03 in) Fitting length 252 mm (9.9 2 in) 253 mm (9.96 in) ---- Preload length <Min.–Max.> 1.5–18 mm (0.06–0.71 in) ← Spring rate, STD K = 56.0 N/mm (5.7 k ...

  • Yamaha YZ450FA - page 48

    2-12 MAINTENANCE SPECIFICATIONS ELECTRICAL Rear disc brake: Disc outside dia.×Thickness 245 × 4.0 mm (9.65 × 0.16 in) 245 × 3.5 mm (9.65 × 0.14 in) Deflection limit ---- 0.15 mm (0.006 in) Pad thickness 6.4 mm (0.25 in) 1.0 mm (0.04 in) Master cylinder inside dia. 11.0 mm (0.433 in) ---- Caliper cylinder inside dia. 25.4 mm (1.000 in) × 1 --- ...

  • Yamaha YZ450FA - page 49

    2-13 TIGHTENING TORQUES TIGHTENING TORQUES ENGINE △ - marked portion shall b e checked for torque tightening after bre ak-in or before each race. Part to be tightened Thread size Q'ty Tightening torque Nm m•kg ft•lb Spark plug M10S × 1.0 1 13 1.3 9.4 Camshaft cap M6 × 1.0 8 10 1. 0 7.2 Cylinder head blind plug screw M12 × 1.0 2 28 2.8 ...

  • Yamaha YZ450FA - page 50

    2-14 TIGHTENING TORQUES Coolant drain bolt M6 × 1.0 1 10 1.0 7.2 Oil pump cover M4 × 0.7 1 2 0.2 1.4 Oil pump M6 × 1.0 2 10 1.0 7.2 Oil pump drive gear shaft M6 × 1.0 1 10 1.0 7.2 Oil filter element cover M6 × 1.0 2 10 1.0 7.2 Oil pressure check bolt M6 × 1.0 2 10 1.0 7.2 Crankshaft end accessing screw M36 × 1. 5 1 10 1.0 7.2 Timing mark acc ...

  • Yamaha YZ450FA - page 51

    2-15 TIGHTENING TORQUES *1: Tighten the cylinder head bolts to 30 Nm (3.0 m• kg, 22 ft•lb) in the proper tigh tening sequence, remove and retighten the cylinder head bolts to 20 Nm (2.0 m•kg, 14 ft•lb) in the proper tightening sequence, and then tighten the cylinde r head bolts further to reach the specified a ngle 150° in the proper tight ...

  • Yamaha YZ450FA - page 52

    2-16 TIGHTENING TORQUES △ Front wheel axle holder M8 × 1.25 4 21 2.1 15 △ Front brake disc and wheel hub M6 × 1.0 6 12 1.2 8.7 △ Rear brake disc and wheel hub M6 × 1.0 6 14 1.4 10 △ Footrest bracket and frame M10 × 1.25 4 55 5.5 40 △ Brake pedal mounting M8 × 1.25 1 26 2.6 19 Brake pedal position locknut M6 × 1.0 1 6 0.6 4.3 △ Rea ...

  • Yamaha YZ450FA - page 53

    2-17 TIGHTENING TORQUES 1. First, tighten the steering rin g nut approximately 38 Nm (3.8 m•kg, 27 ft•lb) by using the steering nut wrench, then loosen the steering ring nut o ne turn. 2. Retighten the steering ring nu t 7 Nm (0.7 m•kg, 5.1 ft•lb). △ Fuel tank mounting boss and frame M10 × 1.2 5 1 20 2.0 14 △ Fuel tank (front) M6 × 1. ...

  • Yamaha YZ450FA - page 54

    2-18 TIGHTENING TORQUES ELECTRICAL Part to be tightened Thread size Q'ty Tightening torque Nm m•kg ft•lb Stator M5 × 0.8 3 8 0.8 5.8 Rotor M12 × 1.25 1 65 6.5 47 Crankshaft position sensor M6 × 1.0 2 10 1.0 7.2 Throttle position sensor M5 × 0.8 1 3 0.3 2.2 Injector M5 × 0.8 2 3 0.3 2.2 Ignition coil M5 × 0.8 2 4 0.4 2.9 Coolant tempe ...

  • Yamaha YZ450FA - page 55

    2-19 TIGHTENING TORQUES GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasten- ers with standard I.S.O. pitch threads. Torque specifications for special components or as- semblies are included in the applicab le sec- tions of this book. To avoid warpage, tigh ten multi-fastener assemblies in a crisscross f ash- ion, in progr ...

  • Yamaha YZ450FA - page 56

    2-20 TIGHTENING TORQUES DEFINITION OF UNITS Unit Read Definition Measure mm millimeter 10 -3 meter Length cm centimeter 10 -2 meter Length kg kilogram 10 3 gram Weight N Newton 1 kg × m/sec 2 Force Nm Newton meter N × m Torque m•kg Meter kilogram m × kg Torque Pa Pascal N/m 2 Pressure N/mm Newton per millimeter N/mm Spring rate L Liter — Vol ...

  • Yamaha YZ450FA - page 57

    ...

  • Yamaha YZ450FA - page 58

    2-21 LUBRICATION DIAGRAMS LUBRICATION DIAGRAMS ...

  • Yamaha YZ450FA - page 59

    2-22 LUBRICATION DIAGRAMS 1. Oil strainer 2. Oil check bolt 3. Scavenging pump 4. Oil feed pump 5. Oil filter element 6. Crankshaft 7. Oil nozzle 8. Exhaust camshaft 9. Intake camshaft 10. Main axle 11. Drive axle 12. Oil level check window 13. Oil tank ...

  • Yamaha YZ450FA - page 60

    2-23 CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM ...

  • Yamaha YZ450FA - page 61

    2-24 CABLE ROUTING DIAGRAM 1. Fuel tank breather hose 2. Coupler for connecting optiona l part 3. Cylinder head breather hose 4. Hose holder 5. Radiator hose 3 A. Insert the end of the fuel tank breather hose into the hole in the steering stem. B. Fit the accessory coupler into the connec- tor to fasten it to the bracket. C. Point the end of the cy ...

  • Yamaha YZ450FA - page 62

    2-25 CABLE ROUTING DIAGRAM F-F A B D-D C-C E F F C C D D B A E 100mm ...

  • Yamaha YZ450FA - page 63

    2-26 CABLE ROUTING DIAGRAM 1. Clutch cable 2. Throttle cable (return) 3. Throttle cable (pull) 4. Cable holder 5. Clamp 6. Rectifier/regulator 7. Ignition coil 8. Ignition coil coupler 9. AC magneto coupler 10. Radiator hose 2 11. Ground lead terminal 12. Plug cap 13. Igni tion coil bra cket 14. Clamp (lock) 15. Clamp (clip) 16. AC magneto lead 17. ...

  • Yamaha YZ450FA - page 64

    2-27 CABLE ROUTING DIAGRAM B B F G A-A C-C D-D E-E B-B G F C C D D E E A A ...

  • Yamaha YZ450FA - page 65

    2-28 CABLE ROUTING DIAGRAM 1. Tension pipe 2. Coolant temperature sensor coupler 3. Front engine bracket 4. Fuel pump coupler 5. Fuel pump 6. Intake air temperature sensor coup ler 7. Radiator hose 2 8. Radiator breather hose 9. Radiator hose 1 10. Radiator hose 4 11. Radiator pipe 2 12. Radiator hose 3 13. Cylinder head breather hose 14. Frame 15. ...

  • Yamaha YZ450FA - page 66

    2-29 CABLE ROUTING DIAGRAM ...

  • Yamaha YZ450FA - page 67

    2-30 CABLE ROUTING DIAGRAM 1. Ignition coil coupler 2. Coolant temperature sensor lead 3. Atmospheric pressure sensor coupler 4. Intake air temperature sensor lead 5. Clamp 6. Intake air pressure se nsor coupler 7. Cover 8 Fuel hose 9. Fuel pump lead 10. Fuel injector coupler 11. Throttle body 12. High tension code 13. Throttle cable 14. AC magneto ...

  • Yamaha YZ450FA - page 68

    2-31 CABLE ROUTING DIAGRAM ...

  • Yamaha YZ450FA - page 69

    2-32 CABLE ROUTING DIAGRAM 1. Brake master cylinder 2. Brake hose holder 3. Brake hose A. Install the brake hose so that its pipe por- tion directs as shown and lightly touches the projection on the brake calip er. 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 YZ450FA - page 70

    2-33 CABLE ROUTING DIAGRAM ...

  • Yamaha YZ450FA - page 71

    2-34 CABLE ROUTING DIAGRAM 1. Throttle cable 2. Clutch cable 3. Clamp 4. Engine stop switch lead 5. Hose guide 6. Main harness A. Route the clutch cable to the rear of the number plate band. B. Fasten the engine stop switch lead to the handlebar. C. Route the brake hose to the front of t he number plate. D. Pass the clutch cable through the cable g ...

  • Yamaha YZ450FA - page 72

    3-1 MAINTENANCE INTERVALS REGULAR INSPECTION AND ADJUSTMENTS MAINTENANCE INTERVALS •The following schedule is inte nded as a general guide to mainte nance and lubrication. Bear in mind that such factors as weather, terrain, geographical lo cation, and individual usage will alter the re- quired maintenance and lubrication intervals. If you are a d ...

  • Yamaha YZ450FA - page 73

    3-2 MAINTENANCE INTERVALS PISTON Inspect ● Inspect crack. Clean ● Inspect carbon deposits and eliminate them. Replace ●● Replace the piston, pis- ton pin, piston pin clip, and piston ring all as a set. PISTON RING Inspect ● Check ring end gap. Replace ●● Replace the piston, pis- ton pin, piston pin clip, and piston ring all as a set. ...

  • Yamaha YZ450FA - page 74

    3-3 MAINTENANCE INTERVALS EXHAUST PIPE, SI- LENCER, PROTEC- TOR Inspect and retighten ●● Clean ● Replace fiver ●● * * When the exhaust sound becomes louder or when a performance drop is felt. CRANK Inspect and clean ●● THROTTLE BODY Inspect ● SPARK PLUG Inspect and clean ●● Replace ● DRIVE CHAIN Use chain lube. Lubricate, slac ...

  • Yamaha YZ450FA - page 75

    3-4 MAINTENANCE INTERVALS ENGINE GUARD Replace ● Breakage FRAME Clean and inspect ●● FUEL TANK, FUEL PUMP inspect ●● FUEL HOSE Inspect ● Replace ● Every four years BRAKES Adjust lever position and pedal height ●● Lubricate pivot point ●● Check brake disc sur- face ●● Check fluid level and leakage ●● Retighten brake dis ...

  • Yamaha YZ450FA - page 76

    3-5 MAINTENANCE INTERVALS REAR SHOCK AB- SORBER Inspect and adjust ●● Lube ● (After rain ride) ● Molybdenum disulfide grease Retighten ●● DRIVE CHAIN GUIDE AND ROLLERS Inspect ●● SWINGARM Inspect, lube and re- tighten ●● Molybdenum disulfide grease RELAY ARM, CON- NECTING ROD Inspect, lube and re- tighten ●● Molybdenum disul ...

  • Yamaha YZ450FA - page 77

    3-6 PRE-OPERATION INSPECTION AND MAINTENANCE PRE-OPERATION INSPECTION AND MAINTENANCE Before riding for break-in operation, practice o r a race, make sure the machine is in g ood operating condition. Before using this machine, check the following points. GENERAL INSPECTION AND MAINTENANCE Item Routine Page Coolant Check that coolant is filled up to ...

  • Yamaha YZ450FA - page 78

    3-7 ENGINE ENGINE CHECKING THE COOLANT LEVEL Do not remove the radiator cap "1", drain bolt and hoses when the engine and radia- tor are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury. When the en- gine has cooled, place a thick towel over the radiator cap, slowly rotate the cap counter ...

  • Yamaha YZ450FA - page 79

    3-8 ENGINE • Do not mix more than one type of ethylene glycol antifreeze containing corrosion in- hibitors for aluminum engine. • Do not use water containing impurities 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 eye with water a ...

  • Yamaha YZ450FA - page 80

    3-9 ENGINE CHECKING THE COOLING SYSTEM 1. Inspect: • C oolant le vel 2. Attach: • Radiator cap tester "1" and adapter "2" 3. Apply the specified pressure. • Do not apply pressure more than specified pressure. • Radiator should be filled fully. 4. Inspect: •P r e s s u r e Impossible to maintain the spe cified pres- sur ...

  • Yamaha YZ450FA - page 81

    3-10 ENGINE • Before adjustment, expose the adjuster by moving the boot "3" and cap "4" away. • M ake minute adjustment on the lever sid e us- ing the adjuster "5". • After adjustment, check proper operation of clutch lever. 3. Install: •C a p " 1 " • Boot "2" ADJUSTING THE T HROTTLE CABLE ...

  • Yamaha YZ450FA - page 82

    3-11 ENGINE 2. Apply: • Lithium soap base grease On the throttle cable end "a". 3. Install: • Throttle grip cap • Screw (throttle grip cap) • Cover (grip cap) • Cover (throttle cable cap) CHECKING THE THROTTLE VALVE PULLY COVER DRAIN HOSE Drain the water that stays in the throttle valve pulley cover after a machine wash or a rai ...

  • Yamaha YZ450FA - page 83

    3-12 ENGINE 6. Clean: • Air filter element Clean them with solve nt. After cleaning, remove the remainin g solvent by squeezing the element. • Do not twist the element when squeezing the element. • Leaving too much of solvent in the ele- ment may result in poor starting. 7. Inspect: • Air filter element Damage → Replace. 8. Apply: • Foa ...

  • Yamaha YZ450FA - page 84

    3-13 ENGINE 3. Install: • Air filter • Fuel tank • Air scoop (left/right) • Seat CHECKING THE FUEL LINE 1. Remove: • Seat • Fuel tank • Air scoop (left/right) • Air filter case •C o v e r 2. Check: • Fuel hose "1" Cracks/damage → Replace. Loose connection → Reconnect. 3. Install: •C o v e r • Air filter case ? ...

  • Yamaha YZ450FA - page 85

    3-14 ENGINE CHANGING THE ENGINE OIL 1. Start the engine and let it warm up for sever- al minutes. 2. Stop the engine and place an oil pan under the drain bolt. 3. Remove: • Oil filler cap "1" • Drain bolt (with gasket) "2" • Drain bolt (with gasket) "3" Drain the engine oil. 4. If the oil filter is to be replaced ...

  • Yamaha YZ450FA - page 86

    3-15 ENGINE 7. Install: • Oil filler cap 8. Inspect: • Engine (for oil leaks) •O i l l e v e l CHECKING THE OIL PRESSURE 1. Check: • Oil pressure Checking steps: a. Slightly loosen the oil pressure check bolt "1". b. Start the engine and keep it idling until oil starts to seep from the oil pressure che ck bolt. If no oil comes out ...

  • Yamaha YZ450FA - page 87

    3-16 ENGINE ADJUSTING THE VALVE CLEARAN CE • This section is intended for those who have basic knowledge and skill concerning the ser- vicing of Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning ser- vicing are requested n ot to undertake inspec- tion, adjustment, disa ssembly, ...

  • Yamaha YZ450FA - page 88

    3-17 ENGINE c. Mea sure the valve clearance "e" using a feeler gauge "1". Record the measured reading if the clearance is incorrect. 5. Adjust: • Valve clearance Adjustment steps: a. Remove the camshaft (intake a nd exhaust). Refer to "CAMSHAFTS" section in the CHAPTER 4. b. Remove the valve lifter "1" and ...

  • Yamaha YZ450FA - page 89

    3-18 ENGINE Use the new pad number only as a guide when verifying the valve clearance adjustment. f. Install the new pads "4" and the valve lifters "5". • Apply the engine oil on the valve lifters. • Apply the molybdenum disulfide oil on the valve stem ends. • Valve lifter must turn smoothly when rotated with a finger. • ...

  • Yamaha YZ450FA - page 90

    3-19 ENGINE INTAKE EXHAUST ...

  • Yamaha YZ450FA - page 91

    3-20 CHASSIS CHASSIS BLEEDING THE HYDRAULIC BRAKE SYSTEM Bleed the brake system if: • The system has been disassembled. • A brake hose has been loosened or re- moved. • The brake fluid is very low. • The brake operation is faulty. A dangerous loss of braking perform ance may occur if the brake system is not proper- ly bled. 1. Remove: • B ...

  • Yamaha YZ450FA - page 92

    3-21 CHASSIS 2. Remove: • Brake lever cover 3. Adjust: • Brake lever position Brake lever position adjustment step s: a. Loosen the locknut "1". b. Turn the adjusting bolt "2" until the lever po- sition "a" is within specified po sition. c. Tigh ten the locknut. Be sure to tighten the locknut, as it will cause poor ...

  • Yamaha YZ450FA - page 93

    3-22 CHASSIS CHECKING AND REPLACING THE FRONT BRAKE PADS 1. Inspect: • Brake pad thickness "a" Out of specification → Replace as a set. 2. Replace: •B r a k e p a d Brake pad replacement step s: a. Remove the pad pin plug "1". b. Loosen the pad pin "2". c. Re move the brake caliper "3" from the front fo ...

  • Yamaha YZ450FA - page 94

    3-23 CHASSIS i. Install t he brake caliper "8" and tighten the pad pin "9". j. Inst all the pad pin plug "10". 3. Inspect: •B r a k e f l u i d l e v e l Refer to "CHECKING THE BRAKE FLUID LEVEL" secti on. 4. Check: • Brake lever operation A softy or spongy feeling → Bleed brake sys- tem. Refer to " ...

  • Yamaha YZ450FA - page 95

    3-24 CHASSIS e. Connect the transparent h ose "8" to the bleed screw "9" and place the suitable co n- tainer under its end. f. Loosen the bleed screw and push the brake caliper piston in. Do not reuse the drained brake fluid. g. Tighten the bleed screw. h. Install the brake pad "10" and pad pin "11". • Inst ...

  • Yamaha YZ450FA - page 96

    3-25 CHASSIS 2. Inspect: • Rear brake pad insulator "1" Damage → Replace. CHECKING THE BRAKE FLU ID LEVEL 1. Place the brake master cylinder so that its top is in a horizontal position. 2. Inspect: •B r a k e f l u i d l e v e l Fluid at lower level → Fill up. • Use only designated quality brake fluid to avoid poor brake perform ...

  • Yamaha YZ450FA - page 97

    3-26 CHASSIS 2. Remove: • Master link clip • Joint "1" • D rive chain "2" 3. Clean: • D rive chain Place it in kerosene, and brush off as much dirt as possible. Then remove the drive chain from the kerosene and dry the drive chain. 4. Check: • Drive chain stiffness "a" Clean and oil the drive chain and hold a ...

  • Yamaha YZ450FA - page 98

    3-27 CHASSIS 3. Adjust: • D rive chain slack Drive chain slack adjustment ste ps: a. Loosen the axle nut "1" and locknuts "2". b. Adjust the drive chain slack by turning the adjusters "3". c. Turn each adjuster exactly the same amount to maintain correct axle alignment. (There are marks "a" on each side of ...

  • Yamaha YZ450FA - page 99

    3-28 CHASSIS CLEANING THE FRONT FORK OIL SEAL AND DUST SEAL 1. Remove: •P r o t e c t o r • Dust seal "1" Use a thin screw driver, and be careful not to damage the inner fork tube and dust seal. 2. Clean: • Dust seal "a" •O i l s e a l " b " • Clean the dust seal and oil seal after every run. • Apply the li ...

  • Yamaha YZ450FA - page 100

    3-29 CHASSIS ADJUSTING THE FRONT FORK COMPRESSION DAMPING FORCE 1. Adjust: • Compression damping force By turning the adjuster "1". • STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position. Do not force the adjuster past the minimum or maximum extent of adjustment. Th ...

  • Yamaha YZ450FA - page 101

    3-30 CHASSIS • The I.D. mark "a" is marked at the end of the spring. • Spring specification varies according to the difference in the production lot. 3. Adjust: • Spring preload Adjustment steps: a. Loosen the locknut "1". b. Loosen the adjuster "2" until there is some clearance between the spring and adju ster. ...

  • Yamaha YZ450FA - page 102

    3-31 CHASSIS ADJUSTING THE REAR SHOCK ABSORBER LOW COMPRESSION DAMPING FORCE 1. Adjust: • Low compression damping force By turning the adjuster "1". • STANDARD POSITION: This is the position which is back by the spe- cific number of clicks from the fully turned-in position. (Which align the punch mark "a" on the adjuster wit ...

  • Yamaha YZ450FA - page 103

    3-32 CHASSIS • STANDARD POSITION: This is the position which is back by the spe- cific number of turns from the fully turned-in position. (Which align the punch mark "a" on the adjuster with the punch mark "b" on the adjuster body.) Do not force the adjuster past the minimum or maximum extent of adjustment. The ad - juster may ...

  • Yamaha YZ450FA - page 104

    3-33 CHASSIS CHECKING THE WHEELS 1. Inspect: • Wheel runout Elevate the wheel and turn it. Abnormal runout → Replace. 2. Inspect: • Bearing free play Exist play → Replace. CHECKING AND ADJUSTING THE STEERING HEAD 1. Place a stand under the engine to raise the front wheel off the ground. WARNING! Se- curely support the vehicle so tha t there ...

  • Yamaha YZ450FA - page 105

    3-34 CHASSIS e. Loosen the steering ring nut one turn. f. Retighten the steering ring nut using the steering nut wrench. Avoid over-tightening. g. Check the steering stem by turning it lock to lock. If there is any binding, remove the steering stem assembly and inspect the steering bearings. h. Install the washer "5", upper bra cket " ...

  • Yamaha YZ450FA - page 106

    3-35 CHASSIS LUBRICATION ...

  • Yamaha YZ450FA - page 107

    3-36 CHASSIS To ensure smooth operation of all componen ts, lubricate your machine during setup, after 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 conta ct 6. Drive chain 7. Tube guide cable winding portion 8. Throttle cable end 9. Clutch cable end A. Use ...

  • Yamaha YZ450FA - page 108

    3-37 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 ligh t tan color. Distinctly different color → Check the engine condition. An extended run at low speeds causes the in- sulator to be colore ...

  • Yamaha YZ450FA - page 109

    3-38 ELECTRICAL 4. Check: • Ignition timing Visually check the stationary pointer "a" is within the firing range "b" on the rotor. Incorrect firing range → Check rotor and Crankshaft position sensor. 5. Install: • Timing mark accessing screw Timing mark accessing screw: 6 Nm (0.6 m•kg, 4.3 ft•lb) ...

  • Yamaha YZ450FA - page 110

    3-39 TROUBLESHOOTING TROUBLESHOOTING The following guide for troub leshooting does not cover all the possible causes of proble ms. If the fol- lowing problems occur, perform the specified checks or maintenan ce jobs. If a problem occurs that is not listed in this manual or if the prob lem cannot be corrected by the procedures provided in th is manu ...

  • Yamaha YZ450FA - page 111

    3-40 TROUBLESHOOTING INSPECTION STEPS If the aforementioned problems have occurred, perform the following insp ection steps in the order given. Check that the fuel tank is filled with fresh gasoline. No good → Fill the fuel tank. OK ↓ Check that the fuel tank breather hose is not clogged. (Refer to "INCLUDED PARTS" section in the CHAP ...

  • Yamaha YZ450FA - page 112

    4-1 SEAT AND SIDE COVERS ENGINE This section is intended for those who have basic knowledge and skill concerning the se rvicing of Yamaha motorcycles (e.g., Yamaha dealers, service e ngineers, etc.) Those wh o have little knowl- edge and skill concerning servicing are req uested not to undertake inspect ion, adjustment, disas- sembly, or reassembly ...

  • Yamaha YZ450FA - page 113

    4-2 SEAT AND SIDE COVERS 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 projec- tion before removal. • Remove the clutch cable "2" from the cable guide "b" on the number plate. • ...

  • Yamaha YZ450FA - page 114

    4-3 EXHAUST PIPE AND SILENCER EXHAUST PIPE AND SILENCER REMOVING THE EXHAUST PIPE AND SILENCER Order Part name Q 'ty Remarks Seat Refer to "SEAT AND SIDE COV- ERS" section. Side cover (left and right) Refer to "SEAT AND SIDE COV- ERS" section. Rear fender Refer to "SEAT AND SIDE COV- ERS" section. 1 Bolt (silencer ...

  • Yamaha YZ450FA - page 115

    4-4 EXHAUST PIPE AND SILENCER 10 Exhaust pipe 1 1 11 Gasket 3 12 Heat protector 1 Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 116

    4-5 EXHAUST PIPE AND SILENCER CHECKING THE SILENCER AND EXHAUST PIPE 1. Inspect: •G a s k e t " 1 " Damage → Replace. CHANGING THE SILENCER FIBER For USA and CDN 2. Remove: •B o l t " 1 " • Inner pipe "2" Do not hit the silencer stay " a" as it may do damage to the silencer. Remove the inner pipe wh i ...

  • Yamaha YZ450FA - page 117

    4-6 EXHAUST PIPE AND SILENCER Except for USA and CDN 1. Remove: • Rivet (front) "1" • Inner pipe "2" • Take care not to damage the rivet fitting holes (ø4.9 mm) "a" in removal. • Do not hit the silencer stay "b" as it may do damage to the silencer. Remove the inner pipe wh ile holding the silenc- er ...

  • Yamaha YZ450FA - page 118

    4-7 EXHAUST PIPE AND SILENCER 2. Install: • Silencer clamp (front) • Eexhaust pipe 2 "1" • Bolt (exhaust pipe 2) "2" Install and temporarily tighten the exhaust pipe 2 with its end positioned as shown with respect to the exhaust pipe 1. 3. Install: • Silencer clamp (rear) • Silencer "1" • Bolt (silencer) &q ...

  • Yamaha YZ450FA - page 119

    4-8 RADIATOR RADIATOR REMOVING THE RADIATOR Order Part name Q 'ty Remarks Drain the coola nt. Refer to "CHANGING THE COOL- ANT" section in the CHAPTER 3. Seat Refer to "SEAT AND SIDE COV- ERS" section. Fuel tank Refer to "FUEL TANK" section in the CHAPTER 6. Exhaust pipe Refer to "EXHAUST PIPE AND SI- LENCER& ...

  • Yamaha YZ450FA - page 120

    4-9 RADIATOR 8 Radiator breather hose 1 9 Left radiator 1 10 Radiator hose 1 1 11 Pipe 1/O-ring 1/1 Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 121

    4-10 RADIATOR HANDLING NOTE Do not remove the radiator cap when th e en- gine and radiator are hot. Scalding ho t fluid and steam may be blown out under pres - sure, which could cause serious injury. When the engine has cooled, open the radi- ator cap by the following procedure: Place a thick rag, like a towel, over the radi- ator cap, slowly rotat ...

  • Yamaha YZ450FA - page 122

    4-11 RADIATOR 4. Install: • Radiator breather hose "1" • Right radiator "2" Refer to "CABLE ROUTING DIAGRAM" section in the CHAPTER 2. 5. Install: • Radiator guard "1" First fit the inner hook portion "a" and then the outer one "b" onto the radiator. 6. Install: • Bolt (radiator gu ...

  • Yamaha YZ450FA - page 123

    4-12 CAMSHAFTS CAMSHAFTS REMOVING THE CYLINDER HEAD COVE R Order Part name Q 'ty Remarks Seat Refer to "SEAT AND SIDE COV- ERS" section. Fuel tank Refer to "FUEL TANK" section in the CHAPTER 6. Cover Refer to "THROTTLE BODY" section in the CHAPT ER 6. Engine upper bracket (left) 1 S park plug 1 2 Cylinder head bre ...

  • Yamaha YZ450FA - page 124

    4-13 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 YZ450FA - page 125

    4-14 CAMSHAFTS REMOVING THE CAMSHAFT 1. Remove: • Timing mark accessing screw "1" • Crankshaft end accessing screw "2" 2. Align: • Alignmen mark Checking steps: a. Turn the crankshaft counterclockwise with a wrench. b. Align the alignment mark "a" on the roto r with the alignment mark "b" on the crank- ...

  • Yamaha YZ450FA - page 126

    4-15 CAMSHAFTS CHECKING THE CAMSHAFT 1. Inspect: • Cam lobe Pitting/scratches/blue discoloration → Re- place. 2. Measure: • Cam lobe length "a" and "b" Out of specification → Replace. 3. Measure: • Runout (camshaft) Out of specific ation → Replace. 4. Measure: • Camshaft-to-cap clearance Out of specific ation → M ...

  • Yamaha YZ450FA - page 127

    4-16 CAMSHAFTS c. Inst all the clip, dowel pins and camshaft caps. • Tighten the bolts (camshaft cap) in a criss- cross pattern from innermost to outer cap s. • Do not turn the camshaft when measuring clearance with the Plastigauge ® . d. Remove the camshaft cap s and measure the width of the Plastigauge ® "1". 5. Measure: • Camsh ...

  • Yamaha YZ450FA - page 128

    4-17 CAMSHAFTS INSTALLING THE CAMSHAFT 1. Install: • Exhaust camshaft "1" • Intake camshaft "2" Installation steps: a. Turn the crankshaft counterclockwise with a wrench. • Apply the molybdenum disulfide oil on the camshafts. • Apply the engine oil on the decompression system. • Fill the cylinder head with engine oil u ...

  • Yamaha YZ450FA - page 129

    4-18 CAMSHAFTS d. Install the clips, camshaft caps "4" and bolts (camshaft cap) "5". • Before installing the clips, cover the cylinder head with a clean rag to prevent the clips from into the cylinder head cavity. • Tighten the bolts to the specified torque in two or three steps in the proper tighte ning se- quence as shown. ...

  • Yamaha YZ450FA - page 130

    4-19 CYLINDER HEAD CYLINDER HEAD REMOVING THE CYLINDER HEAD Order Part name Q 'ty Remarks Seat Refer to "SEAT AND SIDE COV- ERS" section. Fuel tank Refer to "FUEL TANK" section in the CHAPTER 6. Exhaust pipe and silencer Refer to "EXHAUST PIPE AND SI- LENCER" section. Radiator Refer to "RADIATOR" section ...

  • Yamaha YZ450FA - page 131

    4-20 CYLINDER HEAD Tighten the cylinder head bolts to 30 Nm (3.0 m•kg , 22 ft•b) in the proper tightening seque nce, re- move and retighten the cylinder head bo lts to 20 Nm (2.0 m•kg, 14 ft•lb) in the proper tightening se- quence, and then tighten th e cylinder head bolts fu rther to reach the specified angle 150° in the proper tightening ...

  • Yamaha YZ450FA - page 132

    4-21 CYLINDER HEAD CHECKING THE CYLINDER HEAD 1. Eliminate: • Carbon deposits (from the combustion chambers) Use a rounded scraper. Do not use a sharp instrument to avoid damag- ing or scratching: • Spark plug threads • Valve seats 2. Inspect: • Cylinder head Scratches/damage → Replace. Replace the titanium valve s with the cylinder head. ...

  • Yamaha YZ450FA - page 133

    4-22 CYLINDER HEAD a. Wash the threads and contact surfaces of the bolts, the contact surfaces of the plain washers, the co ntact surface of the cylinder head, and the threads of the crankcase. b. Apply the molybdenum disulfide grease on the threads and contact surfaces of the bolts and on both contact surfaces of the p lain washers. c. Inst all th ...

  • Yamaha YZ450FA - page 134

    4-23 VALVES AND VALVE SPRINGS VALVES AND VALVE SPRINGS REMOVING THE VALVES AND VALV E SPRINGS Order Part name Q 'ty Remarks Cylinder head Refer to "CYLINDER HEAD" section. 1 Valve lifter 4 Refer to removal section. 2 Adjusting pad 4 Refer to removal section. 3 Valve cotter 8 Refer to removal section. 4 Valve spring retainer 4 5 Valve ...

  • Yamaha YZ450FA - page 135

    4-24 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" position very carefully so that they can be reinstalled in their original place. 2. Check: • Valve sealing Leakage at the valve seat → Inspect the valve ...

  • Yamaha YZ450FA - page 136

    4-25 VALVES AND VALVE SPRINGS 2. Replace: • Valve guide Replacement steps: To ease guide removal, installation and to maintain correct fit heat the cylinder head in an over to 100 °C (212 °F). a. Remove the valve guide using a valve guide remover "1". b. Install the new valve guide using a valve guide remover "1" and valve g ...

  • Yamaha YZ450FA - page 137

    4-26 VALVES AND VALVE SPRINGS 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 re- place the oil seal. 6. Eliminate: • Carbon deposits (from the valve face and valve seat) 7. Inspect: •V a l v e s e a t Pitting/wear → ...

  • Yamaha YZ450FA - page 138

    4-27 VALVES AND VALVE SPRINGS b. Apply molybdenum disulfide oil to the valve stem. c. Inst all the valve into the cylinder head. d. Turn the valve until the valve face and valve seat are evenly polished, the n clean off all of the compound. For best lapping results, lightly tap the valve seat while rotating the valve back and forth be- tween your h ...

  • Yamaha YZ450FA - page 139

    4-28 VALVES AND VALVE SPRINGS 3. Measure: • Spring tilt "a" Out of specification → Replace. CHECKING THE VALVE LIFTERS 1. Inspect: • Valve lifter Scratches/damage → Replace both lifters and cylinder head. INSTALLING THE VALVES 1. Apply: • Molybdenum disulfide oil Onto the valve stem and valve stem se al. 2. Install: •V a l v e ...

  • Yamaha YZ450FA - page 140

    4-29 VALVES AND VALVE SPRINGS 4. To secure the valve cotters onto the valve stem, lightly tap the valve tip with a piece of wood. Hitting the valve tip with excessive forc e could damage the valve. 5. Install: • Adjusting pad "1" • Valve lifter "2" • Apply the molybdenum disulfide oil on the valve stem end. • Apply the e ...

  • Yamaha YZ450FA - page 141

    4-30 CYLINDER AND PISTON CYLINDER AND PISTON REMOVING THE CYLINDER AND PISTON Order Part name Q 'ty Remarks Cylinder head Refer to "CYLINDER HEAD" section. 1 Bolt (cylinder) 1 2 Cylinder 1 3G a s k e t 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 se ...

  • Yamaha YZ450FA - page 142

    4-31 CYLINDER AND PISTON REMOVING THE PISTON AND PISTON RING 1. Remove: • Piston pin clip "1" • Piston pin "2" •P i s t o n " 3 " • Put identification marks on each piston head for reference during reinstallation. • Before removing each piston pin, deburr the clip groove and pin hole area. If the piston pin g ...

  • Yamaha YZ450FA - page 143

    4-32 CYLINDER AND PISTON b. If out of specification, repla ce the cylinder, and replace the piston and piston rings as set. c. Measure th e piston skirt diameter "P" with a micrometer. a. 9 mm (0.35 in) from the piston bottom edge d. If out of specification, repla ce the piston and piston rings as a set. e. Calculate the piston-to-cylin d ...

  • Yamaha YZ450FA - page 144

    4-33 CYLINDER AND PISTON CHECKING THE PISTON PIN 1. Inspect: • Piston pin Blue discoloration/grooves → Replace, then inspect the lubrication system. 2. Measure: • Piston pin-to-piston clearance Measurement steps: a. Measure the outside diameter (piston pin) "a". If out of specification, replace the piston pin. b. Measure the inside ...

  • Yamaha YZ450FA - page 145

    4-34 CYLINDER AND PISTON 3. Install: •P i s t o n " 1 " • Piston pin "2" • Piston pin clip "3" • Apply engine oil onto the piston. • Apply molybdenum disulfide oil onto the pis- ton pin. • Install the piston with the F mark "a" on it pointing to its intake (front) side. • Before installing the p ...

  • Yamaha YZ450FA - page 146

    4-35 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" sec- tion. Clutch cable Disconnect at engine side. 1C l u t c h c o v e r 1 2G a s k e t 1 3C l u t c h s p r i n g 6 4 P ressure plate ...

  • Yamaha YZ450FA - page 147

    4-36 CLUTCH 11 Clutch plate 7 12 Friction plate 8 13 Nut (clutch boss) 1 Refer to removal section. 14 Conical washer 1 Refer to removal section. 15 Clutch boss 1 Refer to removal section. 16 Thrust washer 1 17 Primary driven gear 1 18 Push lever shaft 1 Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 148

    4-37 CLUTCH REMOVING THE CLUTCH BOSS 1. Remove: •N u t " 1 " • Conical washer "2" • Clutch boss "3" Use the clutch hold ing 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 "1" Cracks/wear/damage ...

  • Yamaha YZ450FA - page 149

    4-38 CLUTCH CHECKING THE CLUTCH PLATES 1. Measure: • Clutch plate warpage Out of specification → Replace clutch plate as a set. Use a surface plate "1 " and thickness gauge "2". CHECKING THE PUSH LEVER SHAFT 1. Inspect: • Push lever shaft "1" Wear/damage → Replace. CHECKING THE PUSH ROD 1. Inspect: • Push rod ...

  • Yamaha YZ450FA - page 150

    4-39 CLUTCH 2. Install: • Conical washer "1" • N ut (clutch boss) "2" Make sure to tighten t o specification; other- wise, it may damage the other part that i s fastened together. • Apply engine oil to the threads and contact surface of the clutch boss nut. • Apply engine oil to the contact surfaces of the conical washer ...

  • Yamaha YZ450FA - page 151

    4-40 CLUTCH 5. Install: • Push rod 2 "1" • Ball "2" • Push rod 1 "3" Apply the engine oil on the push rod 1, 2 and ball. 6. Install: • Pressure plate "1" 7. Install: • Clutch spring • Bolt (clutch spring) Tighten the bolts in stage, using a crisscross pattern. 8. Install: • O-ring (clutch cover) ...

  • Yamaha YZ450FA - page 152

    4-41 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" sec- tion. Drain the engine oil. Refer to "CHANGING THE ENGINE OIL" section in the CHAPTER 3. Drain the coola nt. Refer to "C ...

  • Yamaha YZ450FA - page 153

    4-42 OIL FILTER ELEMENT AND WATER PUMP 5 Dowel pin 2 6 Kickstarter crank 1 7 Right crankcase cover 1 8G a s k e t 1 9 Dowel pin/O-ring 3/1 10 Impeller 1 Refer to removal section. 11 Washer 1 Refer to removal section. 12 Impeller shaft 1 Refer to removal section. 13 Oil seal 1 1 Refer to removal section. 14 Oil seal 2 1 Refer to removal section. 15 ...

  • Yamaha YZ450FA - page 154

    4-43 OIL FILTER ELEMENT AND WATER PUMP REMOVING THE IMPELLER SHAFT 1. Remove: • Impeller "1" •W a s h e r " 2 " • Impeller shaft "3" Hold the impeller shaft on its width across the flats "a" with spanners, etc. and remove the im- peller. REMOVING THE OIL SEAL It is not necessary to disassemble the water ...

  • Yamaha YZ450FA - page 155

    4-44 OIL FILTER ELEMENT AND WATER PUMP CHECKING THE BEARING 1. Inspect: • Bearing Rotate inner race with a finger. Rough spot/seizure → Replace. CHECKING THE OIL SEAL 1. Inspect: •O i l s e a l " 1 " Wear/damage → Replace. INSTALLING THE OIL SEAL 1. Install: • Oil seal "1" • Apply the lithium soap base grease on the ...

  • Yamaha YZ450FA - page 156

    4-45 OIL FILTER ELEMENT AND WATER PUMP INSTALLING THE RIGHT CRANKCASE COVER 1. Install: • D owel pin "1" • O-ring "2" • Collar "3" • Gasket "4" Apply the lithium soap base grease on the O- ring. 2. Install: • Right crankcase cover "1" •B o l t " 2 " • Apply the engine oil on ...

  • Yamaha YZ450FA - page 157

    4-46 OIL FILTER ELEMENT AND WATER PUMP INSTALLING THE WATER PUMP HOUSING 1. Install: • D owel pin "1" • Gasket "2" 2. Install: • Water pump housing "1" • Bolt (water pump housing) "2" • Washer "3" • Coolant drain bolt "4" 3. Install: • O-ring • R adiator pipe "1" ...

  • Yamaha YZ450FA - page 158

    4-47 BALANCER BALANCER REMOVING THE BALANCER Order Part name Q 'ty Remarks Primary driven gear Refer to "CLUTCH" section. Right crankcase cover Refer to "OIL FILTER ELEMENT AND WATER PUMP" section. Stator Refer to "AC MAGNETO" section. 1 Nut (balancer) 1 Refer to removal section. 2 Nut (primary drive gear) 1 Refer ...

  • Yamaha YZ450FA - page 159

    4-48 BALANCER 11 Balancer shaft driven gear 1 Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 160

    4-49 BALANCER REMOVING THE BALANCER 1. Straighten the lock washer tab. 2. Loosen: • Nut (balancer) "1" • Nut (primary drive gear) "2" • Nut (balancer shaft driven gear) "3" Place an aluminum plate "a" between the teeth of the balancer shaft drive gear "4" and driven gear "5". CHECKIN ...

  • Yamaha YZ450FA - page 161

    4-50 BALANCER 2. Install: • Balancer shaft driven gear "1" • Align the punched mark "a" on the balancer shaft drive gear with the punch ed mark "b" on the balancer shaft driven gear. • Install the balancer shaft driven gear and crankshaft with the lower splines "c" aligning with each other. 3. Install: ...

  • Yamaha YZ450FA - page 162

    4-51 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 WATER 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 YZ450FA - page 163

    4-52 OIL PUMP 12 Inner rotor 1 1 13 Dowel pin 1 14 Washer 1 15 Oil pump drive shaft 1 16 Rotor housing 1 Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 164

    4-53 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 clearance "b" (between the outer rotor "2" ...

  • Yamaha YZ450FA - page 165

    4-54 OIL PUMP 3. Install: • Oil pump cover "1" • Screw (oil pump cover) "2" • D owel pin "3" • Inner rotor 2 "4" • Circlip "5" • Apply the engine oil on the oil pump drive shaft end and inner rotor 2. • Fit the dowel pin into the groove in the inner rotor 2. 4. Install: • Outer rotor ...

  • Yamaha YZ450FA - page 166

    4-55 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 K ick idle gear 1 2 Kick shaft assembly 1 Refer to removal section. 3 S pring guide 1 4 Torsion spring 1 5 Ratchet wheel 1 6 K ick gear 1 7 K ick shaft 1 8 Washer 1 9 ...

  • Yamaha YZ450FA - page 167

    4-56 KICK SHAFT AND SHIFT SHAFT 14 Shift guide 1 Refer to removal section. 15 Shift lever assembly 1 Refer to removal section. 16 Shift lever 1 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 YZ450FA - page 168

    4-57 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 guide "1" • Shift lever assembly "2&quo ...

  • Yamaha YZ450FA - page 169

    4-58 KICK SHAFT AND SHIFT SHAFT CHECKING THE SHIFT SHAFT 1. Inspect: • Shift shaft "1" Bend/damage → Replace. • Spring "2" Broken → Replace. CHECKING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY 1. Inspect: • Shift guide "1" • Shift lever "2" •P a w l " 3 " • Pawl pin "4" • S ...

  • Yamaha YZ450FA - page 170

    4-59 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 pawl. 2. Install: • Shift lever assembly "1" To shift guide "2". 3. Instal ...

  • Yamaha YZ450FA - page 171

    4-60 KICK SHAFT AND SHIFT SHAFT INSTALLING THE KICK SHAFT ASSEMBLY 1. Install: • Kick gear "1" •W a s h e r " 2 " • Circlip "3" • Ratchet wheel "4" • Spring "5" •W a s h e r " 6 " • Circlip "7" To kick shaft "8". • Apply the molybdenum disulfide oil on t ...

  • Yamaha YZ450FA - page 172

    4-61 KICK SHAFT AND SHIFT SHAFT 5. Hook: • Torsion spring "1" Turn the torsion spring clockwise and hook into the proper hole "a" in the cra nkcase. INSTALLING THE KICK IDLE GEAR 1. Install: • Kick idle gear "1" •W a s h e r " 2 " • Circlip "3" • Apply the engine oil on the kick idle gear ...

  • Yamaha YZ450FA - page 173

    4-62 AC MAGNETO AC MAGNETO REMOVING THE AC MAGNETO Order Part name Q 'ty Remarks Seat Refer to "SEAT AND SIDE COV- ERS" section. Fuel tank Refer to "FUEL TANK" section in the CHAPER 6. Disconnect the AC magneto lead 1 Left crankcase c over 1 2G a s k e t 1 3 Dowel pin 2 4 Nut (rotor) 1 Refer to removal section. 5 Rotor 1 Re ...

  • Yamaha YZ450FA - page 174

    4-63 AC MAGNETO REMOVING THE ROTOR 1. Remove: • Nut (rotor) "1" •W a s h e r 2. Remove: •R o t o r " 1 " Use the rotor puller 2. CHECKING THE AC MAGNETO 1. Inspect: • Rotor inner surface "a" • Stator outer surface "b" Damage → Inspect the crankshaft runout and crankshaft bearing. CHECKING THE WOOD ...

  • Yamaha YZ450FA - page 175

    4-64 AC MAGNETO 2. Install: • Woodruff key "1" •R o t o r " 2 " • Degrease the contact surfaces of the tapered portions of the crankshaft and rotor. • When installing the woodruff key, make sure that its flat surface "a" is in parallel with the crankshaft center line "b". • When installing the rotor ...

  • Yamaha YZ450FA - page 176

    4-65 ENGINE REMOVAL ENGINE REMOVAL REMOVING THE ELECTRONIC PARTS Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the frame. Refer to "HANDLING NOTE". Seat Refer to "SEAT AND SIDE COV- ERS" section. Fuel tank Air filter case Radiator Refer to "RADIATOR" section. 1 Rectifier/regu ...

  • Yamaha YZ450FA - page 177

    4-66 ENGINE REMOVAL REMOVING THE ENGINE Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the frame. Refer to "HANDLING NOTE". Throttle body Refer to "THROTTLE BODY" section in the CHAPRE 6. Rear fender Refer to "SEAT AND SIDE COV- ERS" section. Exhaust pipe and silencer Refer to ...

  • Yamaha YZ450FA - page 178

    4-67 ENGINE REMOVAL 3 Lock washer 1 Refer to removal section. 4 Drive sprocket 1 Refer to removal section. 5C l i p 1 6 Bolt (brake pedal) 1 7 Brake pedal 1 8 Upper engine bracket 2 9 Lower engine bracket 2 10 Engine mounting bolt 4 11 Pivot shaft 1 Refer to removal section. 12 Engine 1 Refer to removal section. Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 179

    4-68 ENGINE REMOVAL HANDLING NOTE Support the machine securely so there is no danger 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 applying the rear brake. 2. Remove: • D rive sprocket "1" • D ...

  • Yamaha YZ450FA - page 180

    4-69 ENGINE REMOVAL • Upper engine bracket "8" • Bolt (upper engine bracket) "9" • Engine mounting bolt (upper) "10" • Apply the molybdenum disulfide grease on the pivot shaft. • Install the patch with the claw "a" facing out- side the chassis. INSTALLING THE BRAKE PEDAL 1. Install: • Spring " ...

  • Yamaha YZ450FA - page 181

    4-70 ENGINE REMOVAL 3. Bend the lock washer tab to lock the nut. 4. Install: • Drive chain sprocket guide • Drive chain sprocket cover "1" • Bolt(drive chain sprocket cover) "2" Bolt (drive chain sprocket cover): 7 Nm (0.7 m•kg, 5.1 ft•lb) ...

  • Yamaha YZ450FA - page 182

    4-71 CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT REMOVING THE CRANKSHAFT Order Part name Q 'ty Remarks Engine Refer to "ENGINE REMOVAL" sec- tion. Piston Refer to "CYLINDER AND PISTON" section. Balancer Refer to "BALANCER" section. Kick shaft asse mbly Refer to "KICK SHAFT AND SHIFT SHAFT" section. ...

  • Yamaha YZ450FA - page 183

    4-72 CRANKCASE AND CRANKSHAFT 6 Bolt [L = 70 mm (2.76 in)] 4 Refer to removal section. 7 Right crankcase 1 Refer to removal section. 8 Left crankcase 1 Refer to removal section. 9 Oil strainer 1 10 Balancer shaft 1 Refer to removal section. 11 Crankshaft 1 Refer to removal section. Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 184

    4-73 CRANKCASE AND CRANKSHAFT REMOVING THE CRANKCASE BEARIN G 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 Circlip 1 2O i l s e a l 3 3 B earing 10 Refer to removal section. ...

  • Yamaha YZ450FA - page 185

    4-74 CRANKCASE AND CRANKSHAFT DISASSEMBLING THE CR ANKCASE 1. Separate: • Right crankcase • Left crankcase Separation steps: a. Remove the crankcase bolts, hose guide and clutch cable holder. Loosen each bolt 1/4 of a turn at a time and af- ter all the bolts are loosened, remove them. b. Remove the right crankcase "1". • Place the c ...

  • Yamaha YZ450FA - page 186

    4-75 CRANKCASE AND CRANKSHAFT REMOVING THE CRANKCASE BEARIN G 1. Remove: • Bearing "1" • Remove the bearing from the crankcase by pressing its inner race. • Do not use the removed bearing. CHECKING THE TIMING CHAIN AND TIMING CHAIN GUIDE 1. Inspect: • Timing chain Cracks/stiff → Replace the timing chain and camshaft sprocket as ...

  • Yamaha YZ450FA - page 187

    4-76 CRANKCASE AND CRANKSHAFT CHECKING THE OIL STRAINER 1. Inspect: • Oil strainer Damage → Replace. INSTALLING THE CRANKCASE BEARING 1. Install: •B e a r i n g • Bearing stopper • Bolt (bearing stopper) • Screw (bearing stopper) • Screw [bearing stopper (crankshaft)] "1" To left and right crankcase. • Install the bearing ...

  • Yamaha YZ450FA - page 188

    4-77 CRANKCASE AND CRANKSHAFT • Hold the connecting rod at top dead center with one hand while turning the nut of the in- stalling tool with the other. Operate the install- ing tool until the crankshaft bottoms against the bearing. • Before installing the crankshaft, clean the contacting surface of crankcase. • Apply the molybdenum disulfide ...

  • Yamaha YZ450FA - page 189

    4-78 CRANKCASE AND CRANKSHAFT 5. Install: • D owel pin "1" • Right crankcase To left crankcase. • Fit the right crankcase onto the left crankcase. Tap lightly on the case with soft hammer. • W hen installing the crankcase, the connecting rod should be positioned at TDC (top dead center). 6. Tighten: • Bolt (crankcase) Tighten th ...

  • Yamaha YZ450FA - page 190

    4-79 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" sec- tion. Separate the crankcase. Refer to "CRANKCASE AND CRANKSHAFT" section. 1 Main axle 1 Refer to removal section. 2 Drive ...

  • Yamaha YZ450FA - page 191

    4-80 TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION 1. Remove: • Main axle "1" •D r i v e a x l e " 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 ...

  • Yamaha YZ450FA - page 192

    4-81 TRANSMISSION, SHIFT CAM AND SHIFT FORK 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, replace not only the shift fork itself but the two gears each adja- cent to the shift fork. INSTALLING TH ...

  • Yamaha YZ450FA - page 193

    4-82 TRANSMISSION, SHIFT CAM AND SHIFT FORK 3. Install: •W a s h e r " 1 " • Circlip "2" • Be sure the circlip sharp-edged corner "a" is positioned opposite side to the washer and gear "b". • Install the circlip with its ends "c" sett led even- ly on the spline crests. 4. Install: • C olla ...

  • Yamaha YZ450FA - page 194

    4-83 TRANSMISSION, SHIFT CAM AND SHIFT FORK 6. Install: • Transmission assembly "1" To left crankcase "2". Apply the engine oil on th e bearings and guide bars. 7. Check: • Shifter operation • Transmission operation Unsmooth operation → Repair. ...

  • Yamaha YZ450FA - page 195

    5-1 CHASSIS This section is intended for those who have basic knowledge and skill concerning the se rvicing of Yamaha motorcycles (e.g., Yamaha dealers, service e ngineers, etc.) Those wh o have little knowl- edge and skill concerning servicing are req uested not to undertake inspect ion, adjustment, disas- sembly, or reassembly only by reference t ...

  • Yamaha YZ450FA - page 196

    5-2 FRONT WHEEL AND REAR WHEEL FRONT WHEEL AND REAR WHEEL REMOVING THE FRONT WHEEL Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. Refer to "HANDLING NOTE". 1 Bolt (axle holder) 4 Only loosening. 2 Nut (front wheel axle) 1 3 Front wheel axle 1 4 Front wheel 1 5 Collar 2 6O i l s e a l ...

  • Yamaha YZ450FA - page 197

    5-3 FRONT WHEEL AND REAR WHEEL REMOVING THE REAR WHEEL Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. Refer to "HANDLING NOTE". 1 Nut (rear wheel axle) 1 2 R ear wheel axle 1 3 Drive chain puller 2 4 Rear wheel 1 Refer to removal section. 5 Collar 2 6 Rear wheel sprocket 1 7O i l s e ...

  • Yamaha YZ450FA - page 198

    5-4 FRONT WHEEL AND REAR WHEEL HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE REAR WHEEL 1. Remove: • Wheel "1" Push the wheel forward and remove the d rive chain "2". REMOVING THE WHEEL BEARING 1. Remove: • Bearing "1" Remove the bearing using a general b earing p ...

  • Yamaha YZ450FA - page 199

    5-5 FRONT WHEEL AND REAR WHEEL CHECKING THE BRAKE DISC 1. Measure: • Brake disc deflection (only rear brake disc) Use the dial gauge "1". Out of specification → Inspect wheel runout. If wheel runout is in good condition, replace the brake disc. 2. Measure: • Brake disc thickness "a" Out of limit → Replace. INSTALLING THE ...

  • Yamaha YZ450FA - page 200

    5-6 FRONT WHEEL AND REAR WHEEL 3. Install: • Collar "1" • Apply the lithium soap base grease on the oil seal lip. • Install the collars with their projections "a" fac- ing the wheel. 4. Install: • Wheel Install the brake disc "1" between the brake pads "2" correctly. 5. Install: • Wheel axle "1 ...

  • Yamaha YZ450FA - page 201

    5-7 FRONT WHEEL AND REAR WHEEL INSTALLING THE REAR WHEEL 1. Install: • Bearing (right) "1" • Circlip "2" • Spacer "3" • Bearing (left) "4" • Oil seal "5" • Apply the lithium soap base grease on the bearing and oil seal lip when installing. • Install the bearing with seal facing outward ...

  • Yamaha YZ450FA - page 202

    5-8 FRONT WHEEL AND REAR WHEEL 5. Install: • Wheel Install the brake disc "1" between the brake pads "2" correctly. 6. Install: • D rive chain "1" Push the wheel "2" forward and install the dr ive chain. 7. Install: • Left drive chain puller "1" • Wheel axle "2" • Install the lef ...

  • Yamaha YZ450FA - page 203

    5-9 FRONT BRAKE AND REAR BRAKE FRONT BRAKE AN D REAR BRAKE REMOVING THE FRONT BRAKE Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. Refer to "HANDLING NOTE". Drain the brake fluid. Refer to removal section. 1 B rake hose holder (p rotector) 2 2 U nion bol t 2 3 Brake hose 1 4 Pad pin ...

  • Yamaha YZ450FA - page 204

    5-10 FRONT BRAKE AND REAR BRAKE REMOVING THE REAR BRAKE Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. 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 cylinde ...

  • Yamaha YZ450FA - page 205

    5-11 FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE CALIPER Order P art name Q'ty Remarks A. Front B. Rear AB 1P a d p i n 1 1 2B r a k e p a d 2 2 3 P ad suppor t 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. ...

  • Yamaha YZ450FA - page 206

    5-12 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 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 ...

  • Yamaha YZ450FA - page 207

    5-13 FRONT BRAKE AND REAR BRAKE HANDLING NOTE Support the machine securely so there is no danger 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 h ose "2" to the bleed screw "1" ...

  • Yamaha YZ450FA - page 208

    5-14 FRONT BRAKE AND REAR BRAKE Remove the brake caliper piston seals and brake caliper piston dust seals b y pushing them with a finger. Never attempt to pry out brake caliper pis- ton seals and brake caliper piston dust seals. Replace the brake caliper piston se als and brake caliper piston dust seals whenever a caliper is disassembled. A. Front ...

  • Yamaha YZ450FA - page 209

    5-15 FRONT BRAKE AND REAR BRAKE CHECKING THE BRAKE CALIPER 1. Inspect: • Brake caliper cylinder inner surface "a" Wear/score marks → Replace brake caliper assembly. A. Front B. Rear 2. Inspect: • Brake caliper piston "1" Wear/score marks → Replace brake caliper piston assembly. Replace the brake caliper piston se als and ...

  • Yamaha YZ450FA - page 210

    5-16 FRONT BRAKE AND REAR BRAKE A. Front B. Rear 3. Install: • Brake caliper piston "1" Apply the brake fluid on the piston wa ll. • Install the piston with its shallow de- pressed side "a" facing the brake calip er. • Never force to insert. A. Front B. Rear INSTALLING THE FRONT BRAKE CALIPER 1. Install: • Pad support &q ...

  • Yamaha YZ450FA - page 211

    5-17 FRONT BRAKE AND REAR BRAKE 2. Install: • Brake disc cover "1" • Bolt (brake disc cover) "2" 3. Install: • Brake caliper "1" • Rear wheel "2" Refer to "FRONT WHEEL AND REAR WHEEL" s ection. 4. Tighten: • Pad pin "3" 5. Install: • Pad pin plug "4" INSTALLING THE BR ...

  • Yamaha YZ450FA - page 212

    5-18 FRONT BRAKE AND REAR BRAKE 4. Install: • Brake master cylinder kit "1" • Washer (front brake) "2" • Push rod (rear brake) "2" •C i r c l i p " 3 " • Brake master cylinder boot "4" • Push rod (front brake) "5" To brake master cylinder. • Apply the brake fluid on the brake ...

  • Yamaha YZ450FA - page 213

    5-19 FRONT BRAKE AND REAR BRAKE INSTALLING THE REAR BRAKE MASTER CYLINDER 1. Install: • Copper washer "1" • Brake hose "2" • U nion bolt "3" Always use new copper washers. Install the brake hose so that its pipe po r- tion "a" directs as shown and lightly touch- es the projection "b" on the br ...

  • Yamaha YZ450FA - page 214

    5-20 FRONT BRAKE AND REAR BRAKE INSTALLING THE FRONT BRAKE HOSE 1. Install: • Copper washer "1" • Brake hose "2" • U nion bolt "3" Always use new copper washers. Install the brake hose so that its pipe po r- tion "a" directs as shown and lightly touch- es the projection "b" on the brake calipe ...

  • Yamaha YZ450FA - page 215

    5-21 FRONT BRAKE AND REAR BRAKE INSTALLING THE REAR BRAKE HOSE 1. Install: • Copper washer "1" • Brake hose "2" • U nion bolt "3" Always use new copper washers. Install the brake hose so that its pipe po r- tion "a" directs as shown and lightly touch- es the projection "b" on the brake calipe ...

  • Yamaha YZ450FA - page 216

    5-22 FRONT BRAKE AND REAR BRAKE Brake fluid may erode painte d surfaces or plastic parts. Always clean up spilled fluid immediately. A. Front B. Rear 2. Air bleed: • Brake sy stem Refer to "BLEEDING THE HYDRAULIC BRAKE SYSTEM" section in the CHAPTER 3. 3. Inspect: •B r a k e f l u i d l e v e l Fluid at lower level → Fill up. Refer ...

  • Yamaha YZ450FA - page 217

    5-23 FRONT FORK FRONT FORK REMOVING THE FRONT FORK Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. 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. Number plate R ...

  • Yamaha YZ450FA - page 218

    5-24 FRONT FORK DISASSEMBLING THE FRONT FORK Order Part name Q 'ty Remarks 1A d j u s t e r 1 Drain the fork oil. Refer to removal section. 2 Fork spring 1 3 Dust seal 1 Refer to removal section. 4 Stopper ring 1 Refer to removal section. 5 Inner tube 1 Refer to removal section. 6 Outer tube 1 7P i s t o n m e t a l 1 8 Slide metal 1 9 Oil sea ...

  • Yamaha YZ450FA - page 219

    5-25 FRONT FORK HANDLING NOTE Support the machine securely so there is no danger of it falling over. The front fork requires careful attention. So it is recommended that the front fork be maintain ed at the dealers. To prevent an accidental explosion of a ir, the following instructions should be ob- served: • The front fork with a built-in piston ...

  • Yamaha YZ450FA - page 220

    5-26 FRONT FORK 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 bottoms out and then pull it back quickly ...

  • Yamaha YZ450FA - page 221

    5-27 FRONT FORK CHECKING THE COLLAR 1. Inspect: • Piston metal "1" Wear/damage → Replace. CHECKING THE FORK SPRING 1. Measure: • Fork spring free length "a" Out of specification → Replace. CHECKING THE INNER TUBE 1. Inspect: • Inner tube surface "a" Score marks → Repair or replace. Use #1,000 grit wet sandp ...

  • Yamaha YZ450FA - page 222

    5-28 FRONT FORK 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 solvent. 2. Stretch the damper assembly fu lly. 3. Fill: • Front fork oil "1" To damper assembly. • Be sure to use recommended fork oil. If other oils ...

  • Yamaha YZ450FA - page 223

    5-29 FRONT FORK 7. Loosen: • Compression damping adjuster "1" • Loosen the compression damping adjuster finger tight. • Record the set position of the adjuster (the amount of turning out the fully turned in posi- tion). 8. Install: • Base valve "1" To damper assembly "2". First bring the damper rod pressure to ...

  • Yamaha YZ450FA - page 224

    5-30 FRONT FORK 13.Allow the overflowing oil to escape at the hole "a" in the damper assembly. 14.Check: • Damper assembly smooth movement Tightness/binding/rough spots → Repeat the steps 2 to 13. 15.Install: • Dust seal "1" • Stopper ring "2" • Oil seal "3" • Oil seal washer "4" • Sli ...

  • Yamaha YZ450FA - page 225

    5-31 FRONT FORK 18.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". 19.Install: •O i l s e a l " 1 " Press the oil seal into the outer tub e with fork seal driver "2". 20.Install: • Stopper ring "1& ...

  • Yamaha YZ450FA - page 226

    5-32 FRONT FORK 23.Measure: • Distance "a" Out of specification → Turn into the locknut. 24.Install: • Collar "1" • Fork spring "2" To damper assembly "3". Install the collar with its larger dia. end "a" fac- ing the fork spring. 25.Install: • Damper assembly "1" To inner tube &q ...

  • Yamaha YZ450FA - page 227

    5-33 FRONT FORK 28.Inspect: • Gap "a" between the adjuster "1" and lock- nut "2". Out of specification → Retight en and read- just the locknut. If the adjuster is installe d out of specification, proper damping force cannot be obtained. 29.Tighten: • Adjuster (locknut) "1" Hold the locknut "2" ...

  • Yamaha YZ450FA - page 228

    5-34 FRONT FORK 32.Install: • Damper assembly "1" To outer tube. Temporarily tighten the damper assembly. 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 (upper bracket) yet. 2. Tig ...

  • Yamaha YZ450FA - page 229

    5-35 FRONT FORK 5. Install: • Protector "1" • Bolt (protector) "2" 6. Adjust: • Rebound damping force Turn in the damping adjuster "1" finge r-tight and then turn out to the originally set position. 7. Adjust: • Compression damping force Turn in the damping adjuster "1" finge r-tight and then turn out ...

  • Yamaha YZ450FA - page 230

    5-36 HANDLEBAR HANDLEBAR REMOVING THE HANDLEBAR Order Part name Q 'ty Remarks Number plate Remove the band only. 1 Clutch cable 1 Disconnect at the lever side. 2 Clutch lever holder 1 3 E ngine sto p switch 1 4 Brake master cylinder 1 Refer to removal section. 5 Throttle cable cap 1 6 Throttle cable #1 (pulled) 1 Disconnect at the throttle sid ...

  • Yamaha YZ450FA - page 231

    5-37 HANDLEBAR 14 Handlebar lower holder 2 15 Cap 1 Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 232

    5-38 HANDLEBAR REMOVING THE BRAKE MASTER CYLINDER 1. Remove: • Brake master cylinder bracket "1" • Brake master cylinder "2" • Do not let the brake master cylinder hang on the brake hose. • Keep the brake master cylinder cap side horizontal to prevent air from coming in. REMOVING THE GRIP 1. Remove: •G r i p " 1 & ...

  • Yamaha YZ450FA - page 233

    5-39 HANDLEBAR 2. Install: • Handlebar "1" • Handlebar upper holder "2" • Bolt (handlebar upper holder) "3" • The handlebar upper holder should be in- stalled with the punched mark "a" forward. • Install the handlebar so that the marks "b" are in place on both sides. • Install the handle ...

  • Yamaha YZ450FA - page 234

    5-40 HANDLEBAR 5. Install: • Right grip "1" • Collar "2" Apply the adhesive on the tube guide "3". • Before applying the adhes ive, wipe off grease or oil on the tube guide surface "a" with a lac- quer thinner. • Install the grip to the tube guide so that the grip match mark "b" and tube gui ...

  • Yamaha YZ450FA - page 235

    5-41 HANDLEBAR 9. Install: • Grip cap cover "1" • Cover (throttle cable cap) "2" 10.Install: • Brake master cylinder "1" • Brake master cylinder bracket "2" • Bolt (brake master cylinder bracket) "3" • Install the bracket so that the arrow mark "a" faces upward. • First tight ...

  • Yamaha YZ450FA - page 236

    5-42 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 suit- able stand under the en gine. Refer to "HANDLING NOTE". Number plate Refer to ...

  • Yamaha YZ450FA - page 237

    5-43 STEERING 6 Lower bracket 1 7 B earing race cover 1 8 Upper bearing 1 9 Lower bearing 1 Refer to removal section. 10 Bearing race 2 Refer to removal section. Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 238

    5-44 STEERING HANDLING NOTE Support the machine securely so there is no danger 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 down. REMOVING THE LOWER BEARING 1. Remove: • Lower bearing "1" Use ...

  • Yamaha YZ450FA - page 239

    5-45 STEERING 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 on the bearing and bearing race cover lip ...

  • Yamaha YZ450FA - page 240

    5-46 STEERING 7. Install: • Front fork "1" • Upper bracket "2" • Temporarily tighten the pinch bolts (lower bracket). • Do not tighten the pinch bolts (upper bracket) yet. 8. Install: • Steering stem nut "1" Apply the lithium soap base grease on the con- tact surface of the steering stem nut when in- stalling ...

  • Yamaha YZ450FA - page 241

    5-47 SWINGARM SWINGARM REMOVING THE SWINGARM Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. 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 ped ...

  • Yamaha YZ450FA - page 242

    5-48 SWINGARM DISASSEMBLING THE SWINGARM Order Part name Q 'ty Remarks 1 Relay arm 1 2 Connecting rod 1 3 Collar 2 4O i l s e a l 2 5 Thrust bearing 2 6 Bushing 2 7O i l s e a l 8 8 B earing 10 Refer to removal section. ...

  • Yamaha YZ450FA - page 243

    5-49 SWINGARM HANDLING NOTE Support the machine securely so there is no danger of it falling over. REMOVING THE BEARING 1. Remove: • Bearing "1" Remove the bearing b y pressing its outer race. CHECKING THE SWINGARM 1. Inspect: • Bearing "1" • Bushing "2" Free play exists/unsmooth revolution/rust → Replace beari ...

  • Yamaha YZ450FA - page 244

    5-50 SWINGARM 2. Install: • Bearing "1" •W a s h e r " 2 " •O i l s e a l " 3 " To relay arm. • Apply the molybdenum disulfide grease on the bearing when installing. • Install the bearing by pressing it on the side having the manufacture's marks or numbers. • Apply the molybdenum disulfide grease on th ...

  • Yamaha YZ450FA - page 245

    5-51 SWINGARM INSTALLING THE SWINGARM 1. Install: • Bushing "1" • Thrust bearing "2" •O i l s e a l " 3 " • Collar "4" To swingarm "5". Apply the molybdenum disulfide grease on the bushings, thrust bearings, oil seal lips and con- tact surfaces of the collar and thru st bearing. 2. Install: ...

  • Yamaha YZ450FA - page 246

    5-52 SWINGARM 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 movement "b" Unsmooth movement/bin ...

  • Yamaha YZ450FA - page 247

    5-53 SWINGARM 11.Tighten: • Nut (relay arm) "1" 12.Install: • Bolt (lower chain tensioner) "1" •W a s h e r " 2 " • Collar "3" • Lower chain tensioner "4" • Nut (lower chain tensioner) "5" 13.Install: • Drive chain support "1" • Drive chain support cover "2&q ...

  • Yamaha YZ450FA - page 248

    5-54 REAR SHOCK ABSORBER REAR SHOCK ABSORBER REMOVING THE REAR SHOCK ABSORBER Order Part name Q 'ty Remarks Hold the machine by placing the suit- able stand under the en gine. Refer to "HANDLING NOTE". Seat Refer to "SE AT AND SIDE COV- ERS" section in the CHAPTER 4. Silencer Refer to "EXHAUST PIPE AND SI- LENCER" ...

  • Yamaha YZ450FA - page 249

    5-55 REAR SHOCK ABSORBER 9 Bearing 2 Refer to removal section. Order Part name Q 'ty Remarks ...

  • Yamaha YZ450FA - page 250

    5-56 REAR SHOCK ABSORBER HANDLING NOTE • Support the machine securely so there is no danger of it falling over. • This rear shock absorber is provided with a separate type tank filled with high-pres- sure nitrogen gas. To prevent the danger of explosion, read and understand the fol- lowing information before handling the shock absorber. The man ...

  • Yamaha YZ450FA - page 251

    5-57 REAR SHOCK ABSORBER 3. Remove: • Lower bearing "1" Remove the bearing b y pressing its outer race. CHECKING THE REAR SHOCK ABSOR BER 1. Inspect: • Damper rod "1" Bends/damage → Replace rear shock ab- sorber assembly. • Shock absorber "2" Oil leaks → Replace rear shock absorber as- sembly. Gas leaks → R ...

  • Yamaha YZ450FA - page 252

    5-58 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: • Adjuster " ...

  • Yamaha YZ450FA - page 253

    5-59 REAR SHOCK ABSORBER 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 in- ward. 3. Install: • Rear shock absorber 4. Install: • Bolt (rear shock absorber-frame) "1" ...

  • Yamaha YZ450FA - page 254

    6-1 FUEL SYSTEM This section is intended for those who have basic knowledge and skill concerning the se rvicing of Yamaha motorcycles (e.g., Yamaha dealers, service e ngineers, etc.) Those wh o have little knowl- edge and skill concerning servicing are req uested not to undertake inspect ion, adjustment, disas- sembly, or reassembly only by referen ...

  • Yamaha YZ450FA - page 255

    6-2 FUEL TANK FUEL TANK REMOVING THE FUEL TANK Order Part name Q 'ty Remarks Seat Refer to "SEAT AND SIDE COV- ERS" section in the chapter 4. Air scoop (left/right) 1/1 Refer to "SEAT AND SIDE COV- ERS" section in the chapter 4. 1 Fuel pump coupler 1 Disconnect. 2 Fuel hose 1 Refer to removal section. 3 Fuel tank bolt 2 4 F ...

  • Yamaha YZ450FA - page 256

    6-3 FUEL TANK REMOVING THE FUEL TANK 1. Extract the fuel in the fuel tank through the fuel tank cap with a pump. Be careful not to damage the fuel pump. 2. Remove: • Fuel pump coupler Although the fuel has been removed fro m the fuel tank be careful when re moving the fuel hoses, since there may be fuel remain- ing in it. • Before disconnecting ...

  • Yamaha YZ450FA - page 257

    6-4 FUEL TANK CHECKING THE FUEL PUMP BODY 1. Check: • Fuel pump body Cracks/damage → Replace fuel pump as- sembly. CHECKING THE FUEL PUMP OPERATION 1. Check: • Fuel pump operation Refer to "CHECKING THE FUEL PRES- SURE" section. INSTALLING THE FUEL PUMP 1. Install: • Fuel pump • Fuel pump bracket • Do not damage the installati ...

  • Yamaha YZ450FA - page 258

    6-5 FUEL TANK 2. Install: • Fuel pump coupler • Air scoop (left/right) • Seat Refer to "SEAT AND SIDE COVERS" in the chapter 4. CHECKING THE FUEL PRESSURE 1. Check: • Pressure regulator operation 2. Remove the fuel tank. Refer to "REMOVEING THE FUEL TANK" section. 3. Connect the pressure gauge "1" and ad apt- e ...

  • Yamaha YZ450FA - page 259

    6-6 THROTTLE BODY THROTTLE BODY REMOVING THE THROTTLE BODY Order Part name Q 'ty Remarks Seat Refer to "SEAT AND SIDE COV- ERS" section in the chapter 4. Air scoop (left/right) Refer to "SEAT AND SIDE COV- ERS" section in the chapter 4. Fuel tank Refer to "FUEL TANK" section. 1C o v e r 1 2 A ir filter case 1 3 Fu ...

  • Yamaha YZ450FA - page 260

    6-7 THROTTLE BODY DISASSEMBLING THE THROTTLE BODY Order Part name Q 'ty Remarks 1 Injector 1 2G a s k e t 2 ...

  • Yamaha YZ450FA - page 261

    6-8 THROTTLE BODY CHECKING THE INJECTOR Replace the fuel injector with a new one if you have dropped or impacted it. 1. Check: •I n j e c t o r s Damage → Re place. CHECKING THE THROTTLE BODY • Before removing the throttle body, clean the area around the throttle body to pre- vent dirt and other foreign material from falling into the engine. ...

  • Yamaha YZ450FA - page 262

    6-9 THROTTLE BODY INSTALLING THE THROTTLE BODY 1. Install: • Throttle body joint "1" • Throttle body "2" • Face the slot "a" in the throttle body joint to- ward the bottom of the vehicle. • Align the slot “a” on the throttle body joint with the projection “b” on the throttle b ody. 2. Install the water- ...

  • Yamaha YZ450FA - page 263

    7-1 ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL This section is intended for those who have basic knowledge and skill concerning the se rvicing of Yamaha motorcycles (e.g., Yamaha dealers, service e ngineers, etc.) Those wh o have little knowl- edge and skill concerning servicing are req uested not to undertake inspect ion, adjustment, disa ...

  • Yamaha YZ450FA - page 264

    7-2 ELECTRICAL COMPONENTS AND WIRING DIAGRAM WIRING DIAGRAM STOP ON Gy Gy B B / L W1 W2 W2 O R / B R R R R R R R Lg Lg Lg L P / W P Y B / R B B B B B BB B B / W B / W B / W Br / W Gy B / L W1 W1 W2 W2 B / Y B / Y Br B / R R / W OO R / B RR R L P / W P YL L LY Br / W B / L B / L B / L B B / L B / L Br W1 Br / W W2 R R O B / L L Y B / L Br R P Gy Gy ...

  • Yamaha YZ450FA - page 265

    7-3 ELECTRICAL COMPONENTS AND WIRING DIAGRAM 1. Crankshaft position sensor 2. AC magneto 3. Rectifier/regulator 4. Condenser 5. Fuel pump 6. Engine stop switch 7. ECU 8. Ignition coil 9. Spark plug 10. Fuel injector 11. Intake air temperature sensor 12. Intake air pressu re sensor 13. Throttle position sensor 14. Atmospheric pressure sensor 15. Coo ...

  • Yamaha YZ450FA - page 266

    7-4 IGNITION SYSTEM IGNITION SYSTEM INSPECTION STEPS Use the following steps for che cking the possibility of the malfunctioning engine be ing attributable to ignition system failure and fo r checking the spark plug which will not spark. *marked: Only when the ignition checker is used. • Remove the following parts before inspection. 1. Seat 2. Fu ...

  • Yamaha YZ450FA - page 267

    7-5 IGNITION SYSTEM SPARK GAP TEST 1. Disconnect the spark plug cap from spark plug. 2. Connect the dynamic spark tester "1" (igni- tion checker "2") as shown. • Spark plug cap "3" • Spark plug "4" A. For USA and CDN B. Except for USA and CDN 3. Kick the kickstarter crank. 4. Check the ignition spark gap. ...

  • Yamaha YZ450FA - page 268

    7-6 IGNITION SYSTEM CHECKING THE IGNITION COIL 1. Remove the ignition coil cap. 2. Inspect: • Primary coil resistance Out of specification → Replace. 3. Inspect: • Secondary coil resistance Out of specification → Replace. Disconnect the spark plug cap before measu r- ing the secondary coil resistance. CHECKING THE AC MAGNETO 1. Inspect: • ...

  • Yamaha YZ450FA - page 269

    7-7 IGNITION SYSTEM CHECKING THE ECU 1. Check: • All electrical components. 2. Check: • ECU installation status Make sure that the ECU is installed correct- ly. • The lean angle sensor is built into the ECU. • The lean angle sensor stops the engine in case of a turnover. • To ensure that the lean angle sensor operates correctly, do not ch ...

  • Yamaha YZ450FA - page 270

    7-8 THROTTLE POSITION SENSOR SYSTEM THROTTLE POSITION SENSOR SYSTEM INSPECTION STEPS If the throttle position sensor will not operate, use t he following inspection steps. *marked: Refer to "IGNITION SYSTEM" section. Use the following special too ls in this inspection. Check entire ignition system for connec- tion. No good → Repair or r ...

  • Yamaha YZ450FA - page 271

    7-9 THROTTLE POSITION SENSOR SYSTEM HANDLING NOTE Do not loosen the screw (throttle position sensor) "1" except when changing the throttle position sensor due to failure be- cause it will cause a drop in engine perfor- mance. CHECKING THE COUPLERS AND LEADS CONNECTION 1. Check: • Couplers and leads connection Rust/dust/looseness/short-c ...

  • Yamaha YZ450FA - page 272

    7-10 THROTTLE POSITION SENSOR SYSTEM 3. Replace: • Throttle position sensor 4. Install: • Throttle position sensor "1" • Screw (throttle position sensor) "2" • Align the projection "b" on the throttle body with the slot "a" in the throttle position sen sor. • Temporarily tighten the screw (throttle ...

  • Yamaha YZ450FA - page 273

    7-11 FUEL INJECTION SYSTEM FUEL INJECTION SYSTEM TROUBLESHOOTING METHOD Engine starting problems, engine idling sp eed problems, and medium and high-speed perfor- mance problems 1. CHECK: • R efer to "TROUBLESHOOTING" sect ion in the chapter 3. 2. Connect the FI diagnost ic tool. (Refer to "CONNECTING THE FI DIAGNOSTIC TOOL".) ...

  • Yamaha YZ450FA - page 274

    7-12 FUEL INJECTION SYSTEM CHECKING THE FAULT CODES 1. Set the switch on the FI diagnostic tool sub- wire harness to "ON". When the switch on the FI diagnostic tool sub- wire harness is set to "ON", make sure that "Waiting for connection" is displaye d on the LCD of the FI diagnostic tool. 2. Check: • Fault code numb ...

  • Yamaha YZ450FA - page 275

    7-13 FUEL INJECTION SYSTEM SENSOR OPERATION TABLE Diag- nostic code No. Item Actuation or display Checking method Actuation or LCD standard display values D01 Throttle angle Display Displays the throttle angle. 0–125° Check with throttle fully closed. When throttle is fully closed:15–19° Check with throttle fully open. When throttle is fully ...

  • Yamaha YZ450FA - page 276

    7-14 FUEL INJECTION SYSTEM D06 Coolant tempera- ture Display Displays the coolant t em- perature. • Check the coolant temper- ature. -20–150°C Cold engine: Displayed tem- perature is close to the ambi- ent temperature. Warm engine: Displayed temperature is the current coolant temperature. D08 Lean angle sen- sor Display Displays the lean angle ...

  • Yamaha YZ450FA - page 277

    7-15 FUEL INJECTION SYSTEM D61 Malfunction histo- ry code display. Display Displays the fault code num- bers that are stored in the malfunction history. If code numbers more than one are detected, the dis- play alternates every two seconds to show all the de- tected code numbers. When all code numbers are shown, the display repeat s the same proces ...

  • Yamaha YZ450FA - page 278

    7-16 FUEL INJECTION SYSTEM TROUBLESHOOTING DETAILS This section describes t he countermeasures per fault code numbe r displayed on the FI diagnostic tool. Check and service the items or components that are the probable cause of the malfunction fol- lowing the order given. After the ch eck and service of the malfunctioning part have been complet ed, ...

  • Yamaha YZ450FA - page 279

    7-17 FUEL INJECTION SYSTEM If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault code No. 13 first. 4 Installed condition of sensor. Check that the gap be tween the crank- shaft position sensor and the r otor is 0.85 mm. Check that the sensor is in- stalled securely an d that there are no pinched leads.C ...

  • Yamaha YZ450FA - page 280

    7-18 FUEL INJECTION SYSTEM Fault code No. 13 Symptom Intake air pressure sensor sig nal is not received properly. Fail-safe system Able to start Able to drive Diagnostic code No. D03 FI diagnostic tool dis- play Intake air pressure Checking method Crank the engine. (If the display value changes, the performa nce is OK.) Item Item/components and pro ...

  • Yamaha YZ450FA - page 281

    7-19 FUEL INJECTION SYSTEM If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault code No. 13 first. 4 Installed condition of sensor. Make sure that the installation position is correct. Check that the sensor is in- stalled securely an d that there are no pinched leads.Check that the ECU is installed secu ...

  • Yamaha YZ450FA - page 282

    7-20 FUEL INJECTION SYSTEM Fault code No. 14 Symptom Intake air pressure sensor system malfunction detected. (clogge d hole or disconnected sensor) Fail-safe system Able to start Able to drive Diagnostic code No. D03 FI diagnostic tool dis- play Intake air pressure Checking method Crank the engine. (If the display value changes, the performa nce is ...

  • Yamaha YZ450FA - page 283

    7-21 FUEL INJECTION SYSTEM Fault code No. 15 Symptom Throttle position sensor signal is not received properly. Fail-safe system Able to start Able to drive Diagnostic code No. D01 FI diagnostic tool dis- play • 15–19° (Fully closed position) • 95–101° (Fully opened position) Checking method • Check with throttle valves fully closed. • ...

  • Yamaha YZ450FA - page 284

    7-22 FUEL INJECTION SYSTEM 4 Installed condition of sensor. • Make sure that the installation posi- tion is correct. • Make sure that there are no problems with the installation. Check that the sensor is in- stalled securely an d that there are no pinched leads.Check that the ECU is installed securely and that there are no pinched leads. Incorr ...

  • Yamaha YZ450FA - page 285

    7-23 FUEL INJECTION SYSTEM Make sure that the engine is completely cool before checking the coolant temperature sensor. Fault code No. 16 Symptom Signal from throttle position sensor d oes not change. Fail-safe system Able to start Able to drive Diagnostic code No. D01 FI diagnostic tool dis- play •1 5 – 19° (Fully closed position) •9 5 – ...

  • Yamaha YZ450FA - page 286

    7-24 FUEL INJECTION SYSTEM Fault code No. 21 Symptom Coolant temperature sensor signal is not received properly. Fail-safe system Able to start Able to drive Diagnostic code No. D06 FI diagnostic tool dis- play -20–150°C Cold engine: Displayed temperature is close to t he ambient temperature. Warm engine: Displayed temperatur e is the current co ...

  • Yamaha YZ450FA - page 287

    7-25 FUEL INJECTION SYSTEM Make sure that the engine is complete ly cool before checking the intake air temperature sen- sor. 4 Installed condition of sensor. C heck that the sensor is in- stalled securely an d that there are no pinched leads.Check that the ECU is installed securely and that there are no pinched leads. Incorrect installation → Re ...

  • Yamaha YZ450FA - page 288

    7-26 FUEL INJECTION SYSTEM Fault code No. 22 Symptom Intake air temperature sensor signal is n ot received properly. Fail-safe system Able to start Able to drive Diagnostic code No. D05 FI diagnostic tool dis- play -20 – 100°C Cold engine: Displayed temperature is close to t he ambient temperature. Warm engine: Displayed temperatur e is approxim ...

  • Yamaha YZ450FA - page 289

    7-27 FUEL INJECTION SYSTEM 4 Installed condition of sensor. C heck that the sensor is in- stalled securely an d that there are no pinched leads.Check that the ECU is installed securely and that there are no pinched leads. Incorrect installation → Re- install or repair. Set the switch on the FI diagnostic tool sub- wire harness to "ON", ...

  • Yamaha YZ450FA - page 290

    7-28 FUEL INJECTION SYSTEM Fault code No. 23 Symptom Atmospheric pressure sens or signal is not received properly. Fail-safe system Able to start Able to drive Diagnostic code No. D02 FI diagnostic tool dis- play Atmosphere Checking method Measure the atmospheric pressure. Item Item/components and probable cause Check or maintenance job Checking me ...

  • Yamaha YZ450FA - page 291

    7-29 FUEL INJECTION SYSTEM 4 Installed condition of sensor. C heck that the sensor is in- stalled securely an d that there are no pinched leads.Check that the ECU is installed securely and that there are no pinched leads. Incorrect installation → Re- install or repair. Set the switch on the FI diagnostic tool sub- wire harness to "ON", ...

  • Yamaha YZ450FA - page 292

    7-30 FUEL INJECTION SYSTEM Fault code No. 30 Symptom Turnover of vehicle Fail-safe system Able to start Unable to drive Diagnostic code No. D08 FI diagnostic tool dis- play Lean angle sensor • 1.0 V (Upright) • 4.0 V (Overturned) Checking method Remove the ECU and incline it 45° or more. Item Item/components and probable cause Check or mainten ...

  • Yamaha YZ450FA - page 293

    7-31 FUEL INJECTION SYSTEM Fault code No. 33 Symptom Ignition system circuit signal is not received properly. Fail-safe system Unable to start Unable to drive Diagnostic code No. D30 FI diagnostic tool dis- play Actuates the ignition coil for five times every second. The "WARNING" LED on the FI diagnostic tool comes on each time the ig- n ...

  • Yamaha YZ450FA - page 294

    7-32 FUEL INJECTION SYSTEM 3 Continuity of harness Open or short circuit → Re- place. Between Ignition coil cou- pler and ECU coupler. (Orange–Orange) Start the engine and let it idle for approxi - mately 5 seconds. After completing the above operation, check whether a fault code number is dis- played. Fault code number is not displayed → Ser ...

  • Yamaha YZ450FA - page 295

    7-33 FUEL INJECTION SYSTEM 5 Defective ignition coil. (test the primary coils for continuity) Defective → Replace. Refer to "CHECKING THE IGNITION COIL". Start the engine and let it idle for approxi - mately 5 seconds. After completing the above operation, check whether a fault code number is dis- played. Fault code number is not displa ...

  • Yamaha YZ450FA - page 296

    7-34 FUEL INJECTION SYSTEM Fault code No. 39 Symptom Injection system circuit signal is not received properly. Fail-safe system Unable to start Unable to drive Diagnostic code No. D36 FI diagnostic tool dis- play Actuates the injector for five times every second. The "WARNING" LED on the FI diagnost ic tool comes on each time the fuel inj ...

  • Yamaha YZ450FA - page 297

    7-35 FUEL INJECTION SYSTEM 3 Check the connection and locking con- dition of the wire harness ECU coupler. Disconnect the coupler and check the pins. (bent or broken terminals and locking condition of the pins) Poor connecti on → Properly connect, repair, or replace. Start the engine and let it idle for approxi - mately 5 seconds. After completin ...

  • Yamaha YZ450FA - page 298

    7-36 FUEL INJECTION SYSTEM Fault code No. 41 Symptom Lean angle sensor malfunction. (the sensor is built into the ECU) Fail-safe system Unable to start Unable to drive Diagnostic code No. D08 FI diagnostic tool dis- play Lean angle sensor • 1.0 V (Upright) • 4.0 V (Overturned) Checking method Remove the ECU and incline it 45° or more. Item Ite ...

  • Yamaha YZ450FA - page 299

    7-37 FUEL INJECTION SYSTEM 2 EEPROM data error (CO adjustment value) Change the CO density and write the changed setting on EEPROM. Set the switch on the FI diagnostic tool sub- wire harness to "ON", and then check the fault code display. Fault code number is not displayed → Service is finished. Fault code number is displayed → Re- pe ...

  • Yamaha YZ450FA - page 300

    7-38 FUEL INJECTION SYSTEM Fault code No. 46 Symptom Power supply to the ECU is not normal. Fail-safe system Able to start (depending on circumstances) Able to drive vehicle (depending on circumstances) Diagnostic code No. — FI diagnostic tool dis- play — Checking method — Item Item/components and probable cause Check or maintenance job Check ...

  • Yamaha YZ450FA - page 301

    7-39 FUEL INJECTION SYSTEM 3 Malfunction of the rectifier/regulator. Defective → Replace. Refer to "CHECKING THE RECTIFIER/REGULATOR" section. Start the engine, set the switch on the FI di- agnostic tool sub-wire harness to "OFF" while the engine is idling, and let the en- gine continue to idle for 5 seconds or more. After com ...

  • Yamaha YZ450FA - page 302

    7-40 FUEL INJECTION SYSTEM Fault code No. 50 Symptom ECU internal malfunction Fail-safe system Unable to start Unable to drive Diagnostic code No. — FI diagnostic tool dis- play — Checking method — Item Item/components and probable cause Check or maintenance job Checking method 1 Malfunction in ECU. Replace the ECU. Set the switch on the FI d ...

  • Yamaha YZ450FA - page 303

    7-41 FUEL INJECTION SYSTEM 2 Check the connection and locking con- dition of the wire harness ECU coupler. Disconnect the coupler and check the pins. (bent or broken terminals and locking condition of the pins) Poor connecti on → Properly connect, repair, or replace. Set the switch on the FI diagnostic tool sub- wire harness to "ON", an ...

  • Yamaha YZ450FA - page 304

    7-42 FUEL INJECTION SYSTEM Fault code No. Er-4 Symptom Registered data cannot be received from the FI d iagnostic tool. Fail-safe system Able to start Able to drive Diagnostic code No. — FI diagnostic tool dis- play — Checking method — Item Item/components and probable cause Check or maintenance job Checking method 1 Check the connection and ...

  • Yamaha YZ450FA - page 305

    7-43 FUEL INJECTION SYSTEM 4 FI diagnostic tool malfuncti on Replace the FI diagnostic tool. Set the switch on the FI diagnostic tool sub- wire harness to "ON", and then check the fault code display. Fault code number is not displayed → Service is finished. Fault code number is displayed → Re- fer to item 5. 5 Malfunction in ECU. Repl ...

  • Yamaha YZ450FA - page 306

    7-44 FUEL PUMP SYSTEM FUEL PUMP SYSTEM INSPECTION STEPS If the fuel pump is not operating normally, perf orm the following procedures in the order given. • Remove the following parts before inspection. 1. Seat 2. Side cover (right/left) 3. Fuel tank • Use the following special tools in this inspection. Check engine stop switch. No good → Repl ...

  • Yamaha YZ450FA - page 307

    7-45 ELECTRICAL COMPONENTS ELECTRICAL COMPONENTS CHECKING THE COOLANT TEMPERATURE SENSOR 1. Remove: • Coolant temperature sensor Refer to "REMOVING THE CYLINDER HEAD" section in the CHAPTER 4. • Handle the coolant temperature sensor with special care. • Never subject the coolant temperature sensor to strong shocks. If the coola nt t ...

  • Yamaha YZ450FA - page 308

    7-46 ELECTRICAL COMPONENTS CHECKING THE INTAKE AIR TEMPERATURE SENSOR 1. Remove: • Intake air temperature sensor (from the air filter case.) • Handle the intake air temperature sensor with special care. • Never subject the intake air temperature sensor to strong shocks. If the intak e air temperature sensor is dropped, rep lace it. 2. Check: ...

  • Yamaha YZ450FA - page 309

    7-47 ELECTRICAL COMPONENTS CHECKING THE FUEL INJECTORS 1. Remove: • Seat • Fuel tank • Air filter case 2. Check: • Injector resistance 3. Connect: • Tester Tester (+) lead → Injector terminal "1" Tester (-) lead → Injector terminal "2" Out of specification → Replace. Injector resistan ce Tester selector po- sitio ...

  • Yamaha YZ450FA - page 310

    8-1 CHASSIS TUNING CHASSIS SELECTION OF THE SECONDARY REDUCTION RATIO (SPROCKET) <Requirement for selection of secondary gear reduction ratio> • It is generally said that the secondary gear ra- tio should be reduced for a longer straight por- tion of a speed course and sh ould be increased for a course with many corners. Ac- tually, however ...

  • Yamaha YZ450FA - page 311

    8-2 CHASSIS TIRE PRESSURE Tire pressure should be adjust to suit the road surface condition of th e circuit. • Under a rainy, muddy, sandy, or slippery con- dition, the tire pressure shou ld be lower for a larger area of contact with the road surface. • Under a stony or hard road condition, the tire pressure should be higher to pr event a flat ...

  • Yamaha YZ450FA - page 312

    8-3 CHASSIS 2. Use of stiff spring • Change the rebound damping. Turn in one or two clicks. • Change the compression damping. Turn out one or two clicks. Generally a stiff spring give s a stiff riding feel- ing. Rebound damping tend s to become weak- er, resulting in lack of a sense of contact with the road surface or in a vibrating handlebar. ...

  • Yamaha YZ450FA - page 313

    8-4 CHASSIS • If the machine is new and after it is broken in, the same set length of the spring may change because of the initial fatigue, etc. of the spring. Therefore, be sure to make reevalua- tion. • If the standard figure cannot be achieved by adjusting the spring adjuster and changing the spring set length, replace the spring with an opt ...

  • Yamaha YZ450FA - page 314

    8-5 CHASSIS • Extent of adjustment (spring preload) For the spring preload adjustment, ref er to "AD- JUSTING THE REAR SHOCK ABSORBER SPRING PR ELOAD" in the CH APTER 3. Maximum Minimum 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 ...

  • Yamaha YZ450FA - page 315

    8-6 CHASSIS SUSPENSION SETTING (FRONT FORK) • If any of the following symptoms is experienced with the standard position as the base, make reset- ting by reference to the adjustment proce dure given in the same chart. • Before any change, set the rear shock absorber sunken len gth to the standard figure 90–100 mm (3.5–3.9 in). Symptom Secti ...

  • Yamaha YZ450FA - page 316

    8-7 CHASSIS SUSPENSION SETTING (REAR SHOCK ABSORBER) • If any of the following symptoms is experienced with the standard position as the base, make reset- ting by reference to the adjustment proce dure given in the same chart. • Adjust the rebound damping in 2-click increments or decre ments. • Adjust the low compression damping in 1-click in ...

  • Yamaha YZ450FA - page 317

    Q Read this manual carefull y before operating this vehicle. This manual should sta y with this vehicle if it is sold. 33D-9-10_cover 09.7.16 13:11 ページ 2 ...

  • Yamaha YZ450FA - page 318

    PRINTED IN JAP AN 2010.05—0.8 × 1 ! (E) Y AMAHA MO T OR CO . , L TD . 2500 SHINGAI IW A T A SHIZUOKA JAP AN PRINTED ON RECYCLED P APER PROTECT YOUR INVESTMENT Use Genuine YAMAHA Parts And Accessories YZ 450F A 2011 O WNER’S SER VICE MANU AL YZ 450F A 33D-28199-11 LIT -11626-24-22 2011 q Read this manual carefull y before operating this vehic l ...

Manufacturer Yamaha Category Automobile

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A manual, also referred to as a user manual, or simply "instructions" is a technical document designed to assist in the use Yamaha YZ450FA by users. Manuals are usually written by a technical writer, but in a language understandable to all users of Yamaha YZ450FA.

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.

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Leonid

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