C3-9-33_cover 07.6.14 9:59 AM Page 1 2008 YZ125(X) / X1 2008 PRINTED ON RECYCLED PAPER YAMAHA MOTOR CO., LTD. 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN JAPAN 2007.6—1.
1C3-9-33_cover 07.6.
2008 OWNER’S SERVICE MANUAL YZ125(X)/X1 1C3-28199-33-E0
YZ125 (X)/X1 OWNER'S SERVICE MANUAL ©2007 by Yamaha Motor Co., Ltd. 1st Edition, June 2007 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Co., Ltd. is expressly prohibited.
FOREWORD INTRODUCTION Congratulations on your purchase of a Yamaha YZ series. This model is the culmination of Yamaha's vast experience in the production of pacesetting racing machines. It represents the highest grade of craftsmanship and reliability that have made Yamaha a leader. This manual explains operation, inspection, basic maintenance and tuning of your machine. If you have any questions about this manual or your machine, please contact your Yamaha dealer.
TO THE NEW OWNER This manual will provide you with a good basic understanding of features, operation, and basic maintenance and inspection items of this machine. Please read this manual carefully and completely before operating your new machine. If you have any questions regarding the operation or maintenance of your machine, please consult your Yamaha dealer. This manual should be considered a permanent part of this machine and should remain with it even if the machine is subsequently sold.
HOW TO READ DESCRIPTIONS To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each removal and disassembly section. 1. An easy-to-see exploded diagram "1" is provided for removal and disassembly jobs. 2. Numbers "2" are given in the or- 3 der of the jobs in the exploded diagram. A number that is enclosed by a circle indicates a disassembly step. 3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol marks "3".
TABLE OF CONTENTS GENERAL INFORMATION 1 SPECIFICATIONS 2 REGULAR INSPECTION AND ADJUSTMENTS 3 ENGINE 4 CHASSIS 5 ELECTRICAL 6 TUNING 7
CONTENTS CHAPTER 1 GENERAL INFORMATION DESCRIPTION ................. 1-1 MACHINE IDENTIFICATION ............. 1-2 INCLUDED PARTS .......... 1-2 IMPORTANT INFORMATION................. 1-2 CHECKING OF CONNECTION ................................. 1-3 SPECIAL TOOLS ............. 1-4 CONTROL FUNCTIONS .. 1-7 STARTING AND BREAK-IN ........................ 1-7 TORQUE-CHECK POINTS............................. 1-9 CLEANING AND STORAGE ...................... 1-10 CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS .....
DESCRIPTION GENERAL INFORMATION DESCRIPTION 1 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Clutch lever Engine stop switch Front brake lever Throttle grip Radiator cap Fuel tank cap Kickstarter crank Fuel tank Radiator Coolant drain bolt Check bolt (Transmission oil level) Rear brake pedal Valve joint 14. 15. 16. 17. 18. 19. Fuel cock Air filter Drive chain Shift pedal Starter knob Front fork • The machine you have purchased may differ slightly from those shown in the following.
MACHINE IDENTIFICATION MACHINE IDENTIFICATION There are two significant reasons for knowing the serial number of your machine: 1. When ordering parts, you can give the number to your Yamaha dealer for positive identification of the model you own. 2. If your machine is stolen, the authorities will need the number to search for and identify your machine. VEHICLE IDENTIFICATION NUMBER The vehicle identification number "1" is stamped on the right of the steering head pipe.
CHECKING OF CONNECTION ommended by Yamaha for assembly and adjustment. GASKETS, OIL SEALS AND ORINGS 1. All gaskets, oil seals, and O-rings should be replaced when an engine is overhauled. All gasket surfaces, oil seal lips, and O-rings must be cleaned. 2. Properly oil all mating parts and bearings during reassembly. Apply grease to the oil seal lips. LOCK WASHERS/PLATES AND COTTER PINS 1. All lock washers/plates "1" and cotter pins must be replaced when they are removed.
SPECIAL TOOLS SPECIAL TOOLS The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised techniques. The shape and part number used for the special tool differ by country, so two types are provided. Refer to the list provided to avoid errors when placing an order. • For U.S.A. and Canada, use part number starting with "YM-", "YU-" or "ACC-".
SPECIAL TOOLS Tool name/Part number How to use Fuel level gauge "1" YM-1312-A, 90890-01312 Fuel level gauge adaptor "2" YM-01470, 90890-01470 This gauge is used to measure the fuel level in the float chamber. Radiator cap tester YU-24460-01, 90890-01325 Radiator cap tester adapter YU-33984, 90890-01352 These tools are used for checking the cooling system. Flywheel puller YU-33270-B, 90890-01362 These tool is used to split the crankcase.
SPECIAL TOOLS Tool name/Part number How to use Fork seal driver YM-A0948, 90890-01502 This tool is used when install the fork oil seal. Pocket tester YU-3112-C, 90890-03112 Use this tool to inspect the coil resistance, output voltage and amperage. Clutch holding tool YM-91042, 90890-04086 This tool is used to hold the clutch when removing or installing the clutch boss securing nut.
CONTROL FUNCTIONS CONTROL FUNCTIONS ENGINE STOP SWITCH The engine stop switch "1" is located on the left handlebar. Continue pushing the engine stop switch till the engine comes to a stop. THROTTLE GRIP The throttle grip "1" is located on the right handlebar; it accelerates or decelerates the engine. For acceleration, turn the grip toward you; for deceleration, turn it away from you. CLUTCH LEVER The clutch lever "1" is located on the left handlebar; it disengages or engages the clutch.
STARTING AND BREAK-IN Mixing oil: Recommended oil: Yamalube "2-R" (Yamalube racing 2cycle oil) Mixing ratio: 30:1 If unavailable, use an equivalent type of oil. HANDLING NOTE Before starting the machine, perform the checks in the pre-operation check list. Never start or run the engine in a closed area. The exhaust fumes are poisonous; they can cause loss of consciousness and death in a very short time. Always operate the machine in a well-ventilated area. STARTING A COLD ENGINE 1.
TORQUE-CHECK POINTS TORQUE-CHECK POINTS 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 Steering Steering stem to handlebar Steering stem to frame Steering stem to upper bracket Upper bracket to handlebar Suspension Front Steering stem to front fork Rear For link type Front fork to upper bracket Front fork to lower bracket Assembly of lin
CLEANING AND STORAGE CLEANING AND STORAGE CLEANING Frequent cleaning of your machine will enhance its appearance, maintain good overall performance, and extend the life of many components. 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 used for this purpose. 2. If the engine is excessively greasy, apply some degreaser to it with a paint brush. Do not apply degreaser to the chain, sprockets, or wheel axles.
GENERAL SPECIFICATIONS SPECIFICATIONS GENERAL SPECIFICATIONS Model name: YZ125X1 (USA, CDN) YZ125 (EUROPE, ZA) YZ125X (AUS, NZ) Model code number: 1C3D (USA, CDN) 1C3E (EUROPE) 1C3G (AUS, NZ, ZA) Dimensions: USA, AUS, NZ, ZA EUROPE, CDN Overall length 2,135 mm (84.1 in) 2,139 mm (84.2 in) Overall width 827 mm (32.6 in) ← Overall height 1,315 mm (51.8 in) 1,318 mm (51.9 in) Seat height 997 mm (39.3in) 998 mm (39.3 in) Wheelbase 1,443 mm (56.8 in) ← Minimum ground clearance 386 mm (15.
MAINTENANCE SPECIFICATIONS Transmission type Constant mesh, 6-speed Operation Left foot operation Gear ratio: 1st 31/13 (2.385) 2nd 29/15 (1.933) 3rd 27/17 (1.588) 4th 23/17 (1.353) 5th 24/20 (1.200) 6th 23/21 (1.095) Chassis: USA, ZA, AUS, NZ EUROPE, CDN Frame type Semi double cradle ← Caster angle 25.5 ° 25.6 ° Trail 105 mm (4.13 in) 107 mm (4.21 in) Tire: Type With tube Size (front) 80/100-21 51M Size (rear) 100/90-19 57M Tire pressure (front and rear) 100 kPa (1.
MAINTENANCE SPECIFICATIONS Item Out of round limit Standard Limit ---- 0.01 mm (0.0004 in) Piston: Piston size/ 53.957–53.972 mm (2.1243–2.1249 in) ---- 17.5 mm (0.69 in) ---- Piston clearance 0.040–0.045 mmm (0.0016–0.0018 in) 0.1 mm (0.004 in) Piston offset 0.5 mm (0.019 in)/EX-side ---- 14.995–15.000 mm (0.5904–0.5906 in) 14.975 mm (0.5896 in) Plain ---- B=1.0 mm (0.039 in) ---- T=2.35 mm (0.093 in) ---- End gap (installed) 0.5–0.7 mm (0.020–0.028 in) 1.2 mm (0.
MAINTENANCE SPECIFICATIONS Item Warp limit Standard Limit ---- 0.2 mm (0.008 in) 40.1 mm (1.579 in) 38.1 mm (1.500 in) 5 ---- Clutch housing thrust clearance 0.15–0.26 mm (0.006–0.010 in) ---- Clutch housing radial clearance 0.014–0.046 mm (0.0006–0.0018 in) ---- Clutch release method Inner push, cam push ---- Main axle deflection limit ---- 0.01 mm (0.0004 in) Drive axle deflection limit ---- 0.01 mm (0.
MAINTENANCE SPECIFICATIONS Item Standard Limit Water pump: Type Single-suction centrifugal pump ---- CHASSIS Item Standard Limit Steering system: Steering bearing type Front suspension: Taper roller bearing ---- USA, CDN, ZA, AUS, NZ EUROPE ← ← ---- K=4.1 N/mm (0.418 kg/ mm, 23.4 lb/in) ← ---- Yes ← Front fork travel 300 mm (11.8 in) Fork spring free length 454 mm (17.9 in) Spring rate, STD Optional spring 3 449 mm (17.7 in) ---cm3 Oil capacity 524 cm (18.4 Imp oz, 17.
MAINTENANCE SPECIFICATIONS Item Standard Limit Wheel: Front wheel type Spoke wheel ---- Rear wheel type Spoke wheel ---- Front rim size/material 21 × 1.60/Aluminum ---- Rear rim size/material 19 × 1.85/Aluminum ---- Radial ---- 2.0 mm (0.08 in) Lateral ---- 2.0 mm (0.08 in) Rim runout limit: Drive chain: Type/manufacturer DID520DMA2 SDH/DAIDO ---- Number of links 111 links + joint ---- Chain slack 48–58 mm (1.9–2.3 in) ---- Chain length (15 links) ---- 242.9 mm (9.
TIGHTENING TORQUES Item Standard Limit Charging coil 1 resistance (color) 720–1,080 Ωat 20 °C (68 °F) (Green/ White-Black/Red) ---- Charging coil 2 resistance (color) 44–66 Ωat 20 °C (68 °F) (Black-Green/ Blue) ---- Pickup coil resistance (color) 248–372 Ωat 20 °C (68 °F) (White/BlueWhite/Red) ---- CDI unit-model/manufacturer 1C3-10/YAMAHA ---- Model/manufacturer 1C3-00/YAMAHA ---- Minimum spark gap 6 mm (0.24 in) ---- Primary winding resistance 0.24–0.
TIGHTENING TORQUES Part to be tightened Thread size Q'ty Throttle cable adjust bolt and locknut M8 × 1.25 Throttle cable Tightening torque Nm m•kg ft•lb 1 7 0.7 5.1 M6 × 0.75 1 4 0.4 2.9 Crankcase M6 × 1.0 12 14 1.4 10 Right crankcase cover M6 × 1.0 8 10 1.0 7.2 Left crankcase cover M6 × 1.0 4 5 0.5 3.6 Drive chain sprocket cover M6 × 1.0 2 5 0.5 3.6 Bearing plate cover M6 × 1.0 4 10 1.0 7.2 Holder M6 × 1.0 1 10 1.0 7.2 Oil check bolt M6 × 1.
TIGHTENING TORQUES Part to be tightened Bleed screw (front fork) and base valve △ Front fork and front fork protector △ Cable guide (front brake hose) and lower bracket △ Front fork protector and brake hose holder M5 × 0.8 M6 × 1.0 Tightening torque Nm m•kg ft•lb 2 1 0.1 0.7 6 5 0.5 3.6 M6 × 1.0 1 4 0.4 2.9 2 7 0.7 5.1 M4 × 0.7 2 1 0.1 0.7 M6 × 1.0 2 9 0.9 6.5 Brake lever mounting bolt M6 × 1.0 1 6 0.6 4.3 Brake lever mounting nut M6 × 1.0 1 6 0.6 4.
TIGHTENING TORQUES Part to be tightened △ △ △ △ △ Thread size Q'ty Rear shock absorber and frame M10 × 1.25 Rear shock absorber and relay arm m•kg ft•lb 1 56 5.6 40 M10 × 1.25 1 53 5.3 38 Rear frame and frame (upper) M8 × 1.25 1 32 3.2 23 Rear frame and frame (lower) M8 × 1.25 2 29 2.9 21 Swingarm and brake hose holder M5 × 0.8 4 2 0.2 1.4 Swingarm and patch M4 × 0.7 4 2 0.2 1.4 Drive chain tensioner M8 × 1.25 2 16 1.
TIGHTENING TORQUES GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasteners with standard I.S.O. pitch threads. Torque specifications for special components or assemblies are included in the applicable sections of this book. To avoid warpage, tighten multi-fastener assemblies in a crisscross fashion, in progressive stages, until full torque is reached. Unless otherwise specified, torque specifications call for clean, dry threads. Components should be at room temperature.
CABLE ROUTING DIAGRAM CABLE ROUTING DIAGRAM 1. 2. 3. 4. 5. 6. 7. 8. 9. "ENGINE STOP" button lead Throttle cable Clutch cable Ground lead High tension cord Clamp Air vent hose Radiator breather hose CDI magneto lead 10. 11. 12. 13. 14. 15. A. YPVS breather hose Engine bracket (right) Engine bracket (left) Crankcase breather hose Overflow hose Connector cover Pass the clutch cable on the outside of the throttle cable and "ENGINE STOP" button lead. 2-12 B. C.
CABLE ROUTING DIAGRAM D. E. F. G. H. I. J. K. L. M. N. Install the ignition coil, side core and ground lead together to the frame. Take care to fasten the ground lead so that its terminal is within the indicated range. Clamp the throttle cable and high tension cord to the frame. Clamp the clutch cable to the left engine bracket. Clamp the clutch cable below the positioning grommet. Pass the air vent hose back of the throttle cable.
CABLE ROUTING DIAGRAM 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. High tension cord "ENGINE STOP" button lead Ignition coil lead Clamp CDI unit CDI unit band Radiator breather hose CDI magneto lead Connector cover Throttle cable Clutch cable 12. CDI unit stay A. Pass the high tension cord to the left of the radiator hose. B. Using a plastic locking tie, clamp the "ENGINE STOP" button lead, ignition coil lead and CDI magneto lead together with the clamp ends backward and then cut off the tie end. 2-14 C.
CABLE ROUTING DIAGRAM D. E. F. G. H. I. Pass the CDI magneto lead and radiator breather hose between the frame and the radiator(right). Clamp the CDI magneto lead to the frame at its locating tape. Bring the connector cover into contact with the coupler. Locate the clamp ends in the arrowed range. Insert the CDI unit band until it stops at the CDI unit stay. Pass the CDI magneto lead and radiator breather hose between the frame and the radiator hose so that they come within the arrow-indicated range.
CABLE ROUTING DIAGRAM 1. 2. 3. A. B. Master cylinder Brake hose holder Brake hose Install the brake hose so that its pipe portion directs as shown and lightly touches the projection on the caliper. Pass the brake hose into the brake hose holders. C. D. If the brake hose contacts the spring (rear shock absorber), correct its twist. Install the brake hose so that its pipe portion directs as shown and lightly touches the projection on the master cylinder.
CABLE ROUTING DIAGRAM 1. 2. 3. 4. 5. 6. 7. 8. Brake hose Master cylinder "ENGINE STOP" button lead "ENGINE STOP" button Throttle cable Clutch cable Clamp Cable guide A. B. C. Install the brake hose so that its pipe portion directs as shown and lightly touches the projection on the master cylinder. Pass the "ENGINE STOP" button lead in the middle of the clutch holder. Clamp the "ENGINE STOP" button lead to the handlebar. 2-17 D. E.
MAINTENANCE INTERVALS REGULAR INSPECTION AND ADJUSTMENTS MAINTENANCE INTERVALS The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind that such factors as weather, terrain, geographical location, and individual usage will alter the required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer.
MAINTENANCE INTERVALS Item After breakin Every race ● ● Every third Every fifth As required Remarks CARBURETOR Inspect, adjust and clean SPARK PLUG Inspect and clean ● ● ● Replace DRIVE CHAIN Lubricate, slack, alignment Use chain lube. ● ● Chain slack: 48–58 mm (1.9–2.
PRE-OPERATION INSPECTION AND MAINTENANCE After breakin Item Every race Every third Every fifth ● Replace spring seat Retighten Remarks (After rain ride) ● Molybdenum disulfide grease ● Lube As required Every one year ● ● ● ● ● ● Molybdenum disulfide grease ● ● Molybdenum disulfide grease ● ● DRIVE CHAIN GUIDE AND ROLLERS Inspect SWINGARM Inspect, lube and retighten RELAY ARM, CONNECTING ROD Inspect, lube and retighten STEERING HEAD Inspect free play and retighten ● Clean and lube
PRE-OPERATION INSPECTION AND MAINTENANCE Item Routine Wheels Check for excessive wear and tire pressure. Check for loose spokes and have no excessive play. Steering Check that the handlebar can be turned smoothly and have no excessive play. Front forks and rear shock absorber Check that they operate smoothly and there is no oil leakage. Page P.3-15 P.3-15 – 16 P.3-12 – 15 Cables (wires) Check that the clutch and throttle cables move smoothly.
ENGINE ENGINE CHECKING THE COOLANT LEVEL Do not remove the radiator cap "1", drain bolt and hoses when the engine and radiator are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury. When the engine has cooled, place a thick towel over the radiator cap, slowly rotate the cap counterclockwise to the detent. This procedure allows any residual pressure to escape.
ENGINE 2. Apply the specified pressure. Radiator cap opening pressure: 95–125 kPa (0.95–1.25 kg/cm2, 13.5–17.8 psi) 3. Inspect: • Pressure Impossible to maintain the specified pressure for 10 seconds → Replace. CHECKING THE COOLING SYSTEM 1. Inspect: • Coolant level 2. Attach: • Radiator cap tester "1" and adapter "2" Radiator cap tester: YU-24460-01/9089001325 Radiator cap tester adapter: YU-33984/90890-01352 ADJUSTING THE CLUTCH CABLE FREE PLAY 1.
ENGINE • Do not twist the element when squeezing the element. • Leaving too much of solvent in the element may result in poor starting. 2. Apply: • Lithium soap base grease On the throttle cable end "a", tube guide cable winding portion "b" and roller sliding surface "c". 3. Inspect: • Air filter element Damage → Replace. 4. Apply: • Foam-air-filter oil or equivalent oil to the element Squeeze out the excess oil. Element should be wet but not dripping. Transmission oil level checking steps: a.
CHASSIS CHANGING THE TRANSMISSION OIL 1. Start the engine and warm it up for several minutes and wait for five minute. 2. Place the machine on a level place and hold it on upright position by placing the suitable stand under the engine. 3. Place a suitable container under the engine. 4. Remove: • Oil drain bolt "1" • Oil filler cap "2" Drain the transmission oil. of turns. Pilot air screw: 2-1/4 turns out ADJUSTING THE ENGINE IDLING SPEED 1. Start the engine and thoroughly warm it up. 2.
CHASSIS i. Repeat steps (e) to (h) until of the air bubbles have been removed from the system. If bleeding is difficult, it may be necessary to let the brake fluid system stabilize for a few hours. Repeat the bleeding procedure when the tiny bubbles in the system have disappeared. j. Add brake fluid to the level line on the reservoir. Check the operation of the brake after bleeding the brake system. 3.
CHASSIS e. Connect the transparent hose "5" to the bleed screw "6" and place the suitable container 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. Bleed screw: 6 Nm (0.6 m•kg, 4.3 ft•lb) h. Install the brake pads "7" and pad pin. • Install the brake pads with their projections "a" into the brake caliper recesses "b". • Temporarily tighten the pad pin at this point. 3.
CHASSIS j. Tighten the pad pin "14". Pad pin: 18 Nm (1.8 m•kg, 13 ft•lb) so that its top is in a horizontal position. 2. Inspect: • Brake fluid level Fluid at lower level → Fill up. Recommended brake fluid: DOT #4 k. Install the pad pin plug "15" and protector "16". Pad pin plug: 3 Nm (0.3 m•kg, 2.2 ft•lb) Bolt (protector): 7 Nm (0.7 m•kg, 5.1 ft•lb) 3. Inspect: • Brake fluid level Refer to "CHECKING THE BRAKE FLUID LEVEL" section. 4.
CHASSIS clip to the direction as shown. b. Adjust the drive chain slack by turning the adjusters "3". To tighten→Turn the adjuster "3" counterclockwise. To loosen→Turn the adjuster "3" clockwise and push wheel forward. a. Turning direction 6. Lubricate: • Drive chain 2. Clean: • Dust seal "a" • Oil seal "b" Turn the adjuster so that the drive chain is in line with the sprocket, as viewed from the rear. Drive chain slack: 48–58 mm (1.9–2.3 in) d. Tighten the axle nut while pushing down the drive chain.
CHASSIS By turning the adjuster "1". Stiffer "a" → Increase the rebound damping force. (Turn the adjuster "1" in.) Softer "b" → Decrease the rebound damping force. (Turn the adjuster "1" out.) Extent of adjustment: Maximum Minimum Fully turned in position 20 clicks out (from maximum position) 4. Adjust: • Spring preload By turning the adjuster "2". Stiffer → Increase the spring preload. (Turn the adjuster "2" in.) Softer → Decrease the spring preload. (Turn the adjuster "2" out.
CHASSIS • STANDARD POSITION: This is the position which is back by the specific number of clicks from the fully turned-in position. (Which align the punch mark "a" on the adjuster with the punch mark "b" on the high compression damping adjuster.) • STANDARD POSITION: This is the position which is back by the specific number of clicks from the fully turned-in position. (Which align the punch mark "a" on the adjuster with the punch mark "b" on the bracket.
CHASSIS mark "b" on the adjuster body.) Standard position: About 1-1/2 turns out tice or a race check spokes for looseness. Do not force the adjuster past the minimum or maximum extent of adjustment. The adjuster may be damaged. 4. Adjust: • Steering ring nut CHECKING THE WHEELS 1. Inspect: • Wheel runout Elevate the wheel and turn it. Abnormal runout → Replace. CHECKING THE TIRE PRESSURE 1. Measure: • Tire pressure Out of specification → Adjust. Standard tire pressure: 100 kPa (1.
CHASSIS Steering ring nut (final tightening): 7 Nm (0.7 m•kg, 5.1 ft•lb) 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 bracket "6", washer "7", steering stem nut "8", handlebar "9", handlebar upper holder "10" and number plate "11". • The handlebar upper holder should be installed with the punched mark "a" forward.
CHASSIS LUBRICATION To ensure smooth operation of all components, 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 contact 6. Drive chain 7. Throttle roller cable guide 8. Throttle roller sliding surface 9. Tube guide cable winding portion 10. Throttle cable end 11. Clutch cable end A. B. C. Use Yamaha cable lube or equivalent on these areas.
ELECTRICAL ELECTRICAL CHECKING THE SPARK PLUG 1. Remove: • Spark plug 2. Inspect: • Electrode "1" Wear/damage → Replace. • Insulator color "2" Normal condition is a medium to light tan color. Distinctly different color → Check the engine condition. When the engine runs for many hours at low speeds, the spark plug insulator will become sooty, even if the engine and carburetor are in good operating condition. 3. Measure: • Plug gap "a" Use a wire gauge or thickness gauge. Out of specification → Regap.
SEAT, FUEL TANK AND SIDE COVERS ENGINE SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SEAT, FUEL TANK AND SIDE COVERS 19 Nm (1.9 m kg, 13 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 6 Nm (0.6 m kg, 4.3 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 19 Nm (1.9 m kg, 13 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 6 Nm (0.6 m kg, 4.
SEAT, FUEL TANK AND SIDE COVERS REMOVING THE SIDE COVER 1. Remove: • Bolt (side cover) • Side cover (left and right) "1" Draw the side cover downward to remove it because its claws "a" are inserted in the air filter case. REMOVING THE NUMBER PLATE 1. Remove: • Bolt (number plate) • Number plate "1" • The projection "a" is inserted into the band of the number plate. Pull the band off the projection before removal. • Remove the clutch cable "2" from the cable guide "b" on the number plate.
EXHAUST PIPE AND SILENCER EXHAUST PIPE AND SILENCER REMOVING THE EXHAUST PIPE AND SILENCER 12 Nm (1.2 m kg, 8.7 ft lb) 12 Nm (1.2 m kg, 8.7 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 12 Nm (1.2 m kg, 8.7 ft lb) 12 Nm (1.2 m kg, 8.7 ft lb) Order Part name Q'ty Remarks A. For EUROPE Refer to "SEAT, FUEL TANK AND SIDE COVERS" section. Right side cover 1 Bolt (silencer) 2 2 Washer [ø=22 mm (0.87 in)] 1 *2 Washer [ø=26 mm (1.02 in)] 1 3 Silencer 1 4 Collar [L=ø13.0 mm (0.
EXHAUST PIPE AND SILENCER CHANGING THE SILENCER FIBER 1. Remove: • Side cover (right) • Bolt (silencer) "1" • Silencer "2" • Bolt (fiber) "3" 2. • 3. • A. Except for EUROPE B. For EUROPE Remove: Inner pipe "1" Replace: Fiber "2" • Side cover (right) Side cover (right): 7 Nm (0.7 m•kg, 5.1 ft•lb) A. B. Except for EUROPE For EUROPE 4. Install: • Inner pipe Fully apply Quick gasket® (Yamaha bond No.1215) or equivalent as shown. Yamaha bond No.1215 (Three Bond® No.1215): 90890-85505 5.
RADIATOR RADIATOR REMOVING THE RADIATOR 2 Nm (0.2 m kg, 1.4 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) Order Part name Q'ty Remarks Drain the coolant. Refer to "CHANGING THE COOLANT" section in the CHAPTER 3. Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE COVERS" section.
RADIATOR HANDLING NOTE Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be blown out under pressure, which could cause serious injury. When the engine has cooled, open the radiator cap by the following procedure: Place a thick rag, like a towel, over the radiator cap, slowly rotate the cap counterclockwise to the detent. This procedure allows any residual pressure to escape.
CARBURETOR AND REED VALVE CARBURETOR AND REED VALVE REMOVING THE CARBURETOR AND REED VALVE 2 Nm (0.2 m kg, 1.4 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 1 Nm (0.1 m kg, 0.7 ft lb) Order Part name Q'ty Remarks Refer to "SEAT, FUEL TANK AND SIDE COVERS" section. Fuel tank 1 Clamp (carburetor joint) 2 2 Carburetor 1 3 Carburetor joint 1 4 Reed valve assembly 1 5 Stopper (reed valve) 2 6 Reed valve 2 4-7 Loosen the screw (carburetor joint).
CARBURETOR AND REED VALVE DISASSEMBLING THE CARBURETOR 4 Nm (0.4 m kg, 2.9 ft lb) Order Part name Q'ty 1 Mixing chamber top 1 2 Throttle valve 1 3 Needle holder 1 4 Jet needle 1 5 Float chamber 1 6 Needle jet cover 1 7 Float pin 1 8 Float 1 9 Valve seat 1 10 Main jet 1 11 Main jet holder 1 12 Pilot jet 1 13 Starter plunger 1 14 Throttle stop screw 1 15 Pilot air screw 1 4-8 Remarks Refer to removal section.
CARBURETOR AND REED VALVE HANDLING NOTE CHECKING THE JET NEEDLE 1. Inspect: • Jet needle "1" Bends/wear → Replace. • Clip groove Free play exists/wear → Replace. • Clip position Do not disassemble the venturi block "1" and main nozzle "2" because it will cause a drop in carburetor performance. 2. • • • REMOVING THE THROTTLE VALVE 1.
CARBURETOR AND REED VALVE fuel level gauge. Keep the carburetor and fuel level gauge vertically when measuring the fuel level. e. If the fuel level is not within specification, inspect the valve seat and needle valve. f. If either is worn, replace them both. g. If both are fine, adjust the fuel level by bending the float tab "b" on the float. h. Recheck the fuel level. per/Replace valve stopper. Valve stopper height: 8.2–8.6 mm (0.323– 0.339 in) INSTALLING THE REED VALVE 1.
CARBURETOR AND REED VALVE • After installing the needle valve to the float, install them to the carburetor. • Check the float for smooth movement. 2. Tighten: • Bolt (air filter joint) "1" Bolt (air filter joint): 2 Nm (0.2 m•kg, 1.4 ft•lb) 5. • • • Install: Float chamber "1" Plate "2" Screw (float chamber) "3" • Bolt (carburetor joint) "2" 8. Install: • Mixing chamber top "1" • Screw (mixing chamber top) "2" To carburetor "3". Bolt (carburetor joint): 2 Nm (0.2 m•kg, 1.
CYLINDER HEAD, CYLINDER AND PISTON CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE CYLINDER HEAD AND CYLINDER 20 Nm (2.0 m kg, 14 ft lb) 28 Nm (2.8 m kg, 20 ft lb) 34 Nm (3.4 m kg, 24 ft lb) 13 Nm (1.3 m kg, 9.4 ft lb) 30 Nm (3.0 m kg, 22 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) Order Part name Q'ty Remarks Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE COVERS" section. Exhaust pipe and silencer Refer to "EXHAUST PIPE AND SILENCER" section.
CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE PISTON AND POWER VALVE 4 Nm (0.4 m kg, 2.9 ft lb) 8 Nm (0.8 m kg, 5.8 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) Order Part name Q'ty Remarks 1 Piston pin clip 2 Refer to removal section. 2 Piston pin 1 Refer to removal section. 3 Piston 1 Refer to removal section. 4 Small end bearing 1 Refer to removal section. 5 Piston ring 1 Refer to removal section.
CYLINDER HEAD, CYLINDER AND PISTON REMOVING THE PUSH ROD 1. Remove: • Bolt (push rod) "1" • Push rod "2" Set the collar "3" included in owner's tool kit to remove the bolt (push rod). REMOVING THE PISTON AND PISTON RING 1. Remove: • Piston pin clip "1" Before removing the piston pin clip, cover the crankcase with a clean rag to prevent the piston pin clip from falling into the crankcase cavity. 2.
CYLINDER HEAD, CYLINDER AND PISTON Standard Wear limit 54.000– Cylin54.014 mm der bore (2.1260– "C" 2.1265 in) Taper "T" — 5. Check: • Free play There should be no noticeable free play. Free play exists → Inspect the connecting rod for wear/Replace the pin and/or connecting rod as required. 54.1 mm (2.130 in) 0.05 mm (0.0020 in) "C" = Maximum Aa–Cb "T" = (Maximum Aa, or Ab) - (Maximum Ba, or Bb) CHECKING THE PISTON PIN AND SMALL END BEARING 1.
CYLINDER HEAD, CYLINDER AND PISTON 2. Check: • Piston mark "a" CHECKING THE PISTON CLEARANCE 1. Calculate: • Piston clearance Out of limit→Replace piston, and piston ring and/or cylinder. Refer to "Cylinder" and "Piston". Piston mark "a" (color) Piston size A (red) 53.957–53.960 mm (2.1243– 2.1244 in) B (orange) 53.961–53.964 mm (2.1244– 2.1246 in) C (green) 53.965–53.968 mm (2.1246– 2.1247 in) D (purple) 53.969–53.972 mm (2.1248– 2.1249 in) CHECKING THE POWER VALVE HOLE ON CYLINDER 1.
CYLINDER HEAD, CYLINDER AND PISTON INSTALLING THE PISTON RING AND PISTON 1. Install: • Piston ring "1" 3. Install: • Thrust plate "1" • Screw (thrust plate) "2" • Take care not to scratch the piston or damage the piston ring. • Align the piston ring gap with the pin "2". • After installing the piston ring, check the smooth movement of it. • When installing the piston pin clip, use the hand so that it may not be distorted. • Do not allow the clip open ends to meet the piston pin slot "b".
CYLINDER HEAD, CYLINDER AND PISTON Tighten the nuts in stage, using a crisscross pattern. Apply the lithium soap base grease on the O-rings. 4. • • • • 7. • • • Install: Collar "1" Push rod "2" Plain washer "3" Bolt (push rod) "4" Bolt (push rod): 5 Nm (0.5 m•kg, 3.6 ft•lb) • Set the collar "5" included in owner's tool kit to install the bolt (push rod). • Do not forget to remove the collar. Install: Cylinder head "1" Copper washer "2" Nut (cylinder head) "3" Nut (cylinder head): 28 Nm (2.
CLUTCH CLUTCH REMOVING THE CLUTCH 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Drain the transmission oil. Refer to "CHANGING THE TRANSMISSION OIL" section in the CHAPTER 3. Bolt (brake pedal) Shift the brake pedal downward. Rotor and stator Refer to "CDI MAGNETO" section. Clutch cable Disconnect at engine side.
CLUTCH REMOVING THE CLUTCH BOSS 80 Nm (8.0 m kg, 58 ft lb) Order Part name Q'ty Remarks 1 Push rod 1 1 2 Circlip 1 3 Washer 1 4 Bearing 1 5 Ball 1 6 Push rod 2 1 7 Nut (clutch boss) 1 Refer to removal section. 8 Lock washer 1 Refer to removal section. 9 Clutch boss 1 Refer to removal section. 10 Thrust washer [D=ø34mm (1.34 in)] 1 11 Primary driven gear 1 12 Bearing 1 13 Thrust washer [D=ø34mm (1.
CLUTCH REMOVING THE CLUTCH BOSS 1. Remove: • Nut "1" • Lock washer "2" • Clutch boss "3" Straighten the lock washer tab and use the clutch holding tool "4" to hold the clutch boss. Clutch holding tool: YM-91042/90890-04086 CHECKING THE CLUTCH SPRINGS 1. Measure: • Clutch spring free length "a" Out of specification → Replace springs as a set. Clutch spring free length: 40.1 mm (1.579 in) : 38.1 mm (1.500 in) CHECKING THE FRICTION PLATES 1.
CLUTCH 2. Install: • Thrust washer [D=ø34 mm (1.34 in)] "1" • Clutch boss "2" 3. Install: • Lock washer "1" • Nut (clutch boss) "2" Nut (clutch boss): 80 Nm (8.0 m•kg, 58 ft•lb) friction plates and clutch plates. 6. • • • Install: Bearing "1" Washer "2" Circlip "3" To push rod 1 "4". 10. Install: • Dowel pin "1" • Gasket (clutch cover) "2" Apply the lithium soap base grease on the bearing and washer. 11.
KICK SHAFT AND SHIFT SHAFT KICK SHAFT AND SHIFT SHAFT REMOVING THE PRIMARY DRIVE GEAR Order Part name Q'ty Remarks Drain the transmission oil. Refer to "CHANGING THE TRANSMISSION OIL" section in the CHAPTER 3. Clutch cable Disconnect at engine side. Bolt (brake pedal) Shift the brake pedal downward. Radiator hose 4 Disconnect at water pump side. Bolt (push rod) Refer to "CYLINDER HEAD, CYLINDER AND PISTON" section.
KICK SHAFT AND SHIFT SHAFT REMOVING THE KICK SHAFT AND SHIFT SHAFT Order Part name Q'ty Remarks 1 Kick idle gear 1 2 kick shaft assembly 1 3 Shift pedal 1 4 Shift shaft 1 5 Roller 1 6 Shift guide 1 Refer to removal section. 7 Shift lever assembly 1 Refer to removal section. 8 Stopper lever 1 4-24 Refer to removal section.
KICK SHAFT AND SHIFT SHAFT REMOVING THE PRIMARY DRIVE GEAR 1. Loosen: • Bolt (primary drive gear) "1" Place an aluminum plate "a" between the teeth of the primary drive gear "2" and driven gear "3". CHECKING THE KICK GEAR AND KICK IDLE GEAR 1. Inspect: • Kick gear "1" • Kick idle gear "2" • Gear teeth "a" Wear/damage → Replace. REMOVING THE KICK SHAFT ASSEMBLY 1. Remove: • Kick shaft assembly "1" Unhook the torsion spring "2" from the hole "a" in the crankcase. CHECKING THE KICK GEAR CLIP 1.
KICK SHAFT AND SHIFT SHAFT 4. Install: • Bolt (shift guide) "1" Bolt (shift guide): 10 Nm (1.0 m•kg, 7.2 ft•lb) 3. Install: • Kick shaft assembly "1" INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY 1. Install: • Spring "1" • Pawl pin "2" • Pawl "3" To shift lever "4". INSTALLING THE SHIFT SHAFT 1. Install: • Roller "1" • Shift shaft "2" • Apply the transmission oil on the kick shaft.
KICK SHAFT AND SHIFT SHAFT INSTALLING THE PRIMARY DRIVE GEAR 1. Install: • Spacer "1" • Primary drive gear "2" • Bolt "3" Install the primary drive gear with its depressed side toward you. 6. Install: • Bolt [crankcase cover (right)] "1" Bolt [crankcase cover (right)] : 10 Nm (1.0 m•kg, 7.2 ft•lb) Tighten the bolts in stage, using a crisscross pattern. 2. Install: • Primary driven gear Refer to "CLUTCH" section. 3. Tighten: • Bolt (primary drive gear) "1" Bolt (primary drive gear): 48 Nm (4.
YPVS GOVERNOR YPVS GOVERNOR REMOVING THE YPVS GOVERNOR Order Part name Q'ty Remarks Refer to "KICK SHAFT AND SHIFT SHAFT" section. Right crankcase cover 1 Governor assembly 1 2 Dowel pin 1 3 Retainer 1 4 Ball 4 5 Retainer weight 1 6 Plain washer 4 7 Thrust bearing 2 8 Collar 1 9 Plate 1 10 Compression spring 1 11 Governor gear 1 12 Governor shaft 1 4-28 Refer to removal section.
YPVS GOVERNOR REMOVING THE GOVERNOR 1. Remove: • Dowel pin "1" While compressing the spring, remove the dowel pin. CHECKING THE GOVERNOR GROOVE 1. Inspect: • Washer "1" • Collar "2" Wear/Damage → Replace. 2. Install: • Ball "1" • Retainer "2" To governor shaft "3". Apply the transmission oil on the retainer and ball. CHECKING THE BEARING 1. Inspect: • Thrust bearing "1" • Washer "2" Wear/Damage → Replace. 3. Install: • Dowel pin "1" • While compressing the spring, install the dowel pin.
WATER PUMP WATER PUMP DISASSEMBLING THE WATER PUMP Order Part name Q'ty Remarks Refer to "KICK SHAFT AND SHIFT SHAFT" section. Crankcase cover (right) 1 Water pump housing cover 1 2 Impeller shaft gear 1 3 Dowel pin 1 4 Plain washer 1 5 Impeller shaft assembly 1 6 Bearing 1 Refer to removal section. 7 Oil seal 2 Refer to removal section.
WATER PUMP REMOVING THE OIL SEAL • Replace the oil seal when transmission oil or coolant leaks out from the water pump housing hole at the bottom. • Do not reuse the removed bearing and oil seal. 1. Remove: • Bearing "1" 2. Remove: • Oil seal (outside) "1" • Oil seal (inside) "2" CHECKING THE IMPELLER SHAFT 1. Inspect: • Impeller shaft "1" Bend/wear/damage → Replace. Fur deposits → Clean. on the oil seal lip and impeller shaft. And install the shaft while turning it. CHECKING THE OIL SEAL 1.
WATER PUMP 4-32
CDI MAGNETO CDI MAGNETO REMOVING THE CDI MAGNETO Order Part name Q'ty Remarks Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE COVERS" section. Bolt (Radiator) Refer to "RADIATOR" section. Disconnect the CDI magneto lead. 1 Left crankcase cover 1 2 Nut (rotor) 1 Refer to removal section. 3 Rotor 1 Refer to removal section.
CDI MAGNETO REMOVING THE ROTOR 1. Remove: • Nut (rotor) "1" • Washer "2" Use the rotor holding tool "3". Rotor holding tool: YU-1235/90890-01235 2. Remove: • Rotor "1" Use the flywheel puller "2". Flywheel puller: YM-1189/90890-01189 When installing the flywheel puller, turn it counterclockwise. CHECKING THE CDI MAGNETO 1. Inspect: • Rotor inner surface "a" • Stator outer surface "b" Damage→Inspect the crankshaft runout and crankshaft bearing. If necessary, replace CDI magneto and/or stator.
ENGINE REMOVAL ENGINE REMOVAL REMOVING THE ENGINE 26 Nm (2.6 m kg, 19 ft lb) 34 Nm (3.4 m kg, 24 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 85 Nm (8.5 m kg, 61 ft lb) 75 Nm (7.5 m kg, 54 ft lb) Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Seat and fuel tank Refer to "SEAT, FUEL TANK AND SIDE COVERS" section. Carburetor Refer to "CARBURETOR AND REED VALVE" section.
ENGINE REMOVAL 26 Nm (2.6 m kg, 19 ft lb) 34 Nm (3.4 m kg, 24 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 64 Nm (6.4 m kg, 46 ft lb) 85 Nm (8.5 m kg, 61 ft lb) 75 Nm (7.5 m kg, 54 ft lb) Order Part name Q'ty 7 Brake pedal 1 8 Engine bracket 2 Remarks 9 Engine mounting bolt 3 10 Pivot shaft 1 Refer to removal section. 11 Engine 1 Refer to removal section.
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. Spring "1" Brake pedal "2" O-ring "3" Bolt (brake pedal) "4" Bolt (brake pedal): 26 Nm (2.6 m•kg, 19 ft•lb) INSTALLING THE ENGINE 1. Install: • Engine "1" Install the engine from right side.
ENGINE REMOVAL • Screw (drive chain sprocket cover) "3" Screw (drive chain sprocket cover): 5 Nm (0.5 m•kg, 3.
CRANKCASE AND CRANKSHAFT CRANKCASE AND CRANKSHAFT REMOVING THE CRANKSHAFT 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 14 Nm (1.4 m kg, 10 ft lb) 20 Nm (2.0 m kg, 14 ft lb) Order Part name Q'ty Remarks Engine Refer to "ENGINE REMOVAL" section. Piston Refer to "CYLINDER HEAD, CYLINDER AND PISTON" section. Primary drive gear Refer to "KICK SHAFT AND SHIFT SHAFT" section. Kick idle gear Refer to "KICK SHAFT AND SHIFT SHAFT" section.
CRANKCASE AND CRANKSHAFT 30 Nm (3.0 m kg, 22 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) 14 Nm (1.4 m kg, 10 ft lb) 20 Nm (2.0 m kg, 14 ft lb) Order Part name Q'ty 9 Crankshaft 1 10 Oil seal 2 11 Bearing 2 4-40 Remarks Refer to removal section. Refer to removal section.
CRANKCASE AND CRANKSHAFT REMOVING THE SEGMENT 1. Remove: • Bolt (segment) "1" • Segment "2" Turn the segment counterclockwise until it stops and loosen the bolt. If the segment gets an impact, it may be damaged. Take care not to give an impact to the segment when removing the bolt. REMOVING THE CRANKSHAFT 1. Remove: • Crankshaft "1" Use the crankcase separating tool "2". Crankcase separating tool: YU-1135-A/9089001135 CHECKING THE CRANKCASE 1. Inspect: • Contacting surface "a" Scratches → Replace.
CRANKCASE AND CRANKSHAFT Unsmooth operation → Repair. Standard Runout limit: 0.03 mm (0.0012 in) 0.05 mm (0.002 in) Small end free play: 0.8–1.0 mm (0.031– 0.039 in) 2.0 mm (0.08 in) Side clearance: 0.06–0.64 mm (0.002– 0.025 in) — Crack width: 55.90–55.95 mm (2.201– 2.203 in) — INSTALLING THE CRANKCASE BEARING 1. Install: • Bearing "1" To left and right crankcase. Install the bearing by pressing its outer race parallel. INSTALLING THE CRANKSHAFT 1.
CRANKCASE AND CRANKSHAFT ter. (Except for USA and CDN) • When installing the crankcase, the connecting rod should be positioned at TDC (top dead center). • Install while checking that the dowel pin is in place. 8. Install: • Segment "1" • Bolt (segment) "2" Bolt (segment): 30 Nm (3.0 m•kg, 22 ft•lb) • When installing the segment onto the shift cam "3", align the punch mark "a" with the dowel pin "b". • Turn the segment clockwise until it stops and tighten the bolt. (1.77 (0.
TRANSMISSION, SHIFT CAM AND SHIFT FORK TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION, SHIFT CAM AND SHIFT FORK 10 Nm (1.0 m kg, 7.2 ft lb) 10 Nm (1.0 m kg, 7.2 ft lb) Order Part name Q'ty Remarks Engine Refer to "ENGINE REMOVAL" section. Separate the crankcase. Refer to "CRANKCASE AND CRANKSHAFT" section. 1 Guide bar (long) 1 2 Guide bar (short) 1 3 Shift cam 1 4 Shift fork 3 1 5 Shift fork 1 1 6 Shift fork 2 1 7 Main axle 1 Refer to removal section.
TRANSMISSION, SHIFT CAM AND SHIFT FORK REMOVING THE TRANSMISSION 1. Remove: • Main axle "1" • Drive axle "2" • Tap lightly on the transmission drive axle with a soft hammer to remove. • Remove assembly carefully. Note the position of each part. Pay particular attention to the location and direction of shift forks. CHECKING THE GEARS 1. Inspect: • Matching dog "a" • Gear teeth "b" • Shift fork groove "c" Wear/damage → Replace. Wear/damage/scratches place. 2.
TRANSMISSION, SHIFT CAM AND SHIFT FORK 4. Install: • Collar "1" 2. Install: • Shift cam "1" • Apply the lithium soap base grease on the oil seal lip. • When installing the collar into the crankcase, pay careful attention to the crankcase oil seal lip. • Apply the transmission oil on the shift cam. • Install the shift cam while holding up the 5th wheel gear "2" and keeping the shift fork #1 "3" moved in the direction of the arrow. 5.
FRONT WHEEL AND REAR WHEEL CHASSIS FRONT WHEEL AND REAR WHEEL REMOVING THE FRONT WHEEL Order Part name Q'ty Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". 1 Bolt (axle holder) 4 2 Nut (front wheel axle) 1 3 Front wheel axle 1 4 Front wheel 1 5 Collar 2 6 Oil seal 2 7 Bearing 2 8 Brake disc 1 5-1 Remarks Only loosening. Refer to removal section.
FRONT WHEEL AND REAR WHEEL REMOVING THE REAR WHEEL 5 Order Part name Q'ty Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". 1 Nut (rear wheel axle) 1 2 Rear wheel axle 1 3 Drive chain puller 2 4 Rear wheel 1 5 Collar 2 6 Rear wheel sprocket 1 7 Oil seal 2 8 Circlip 1 9 Bearing 2 10 Brake disc 1 5-2 Remarks Refer to removal section. Refer to removal section.
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 drive chain "2". CHECKING THE WHEEL AXLE 1. Measure: • Wheel axle bends Out of specification → Replace. Use the dial gauge "1". Wheel axle bending limit: 0.5 mm (0.020 in) The bending value is shown by one half of the dial gauge reading. REMOVING THE WHEEL BEARING 1.
FRONT WHEEL AND REAR WHEEL • Bolt (brake disc) "2" Bolt (brake disc): 12 Nm (1.2 m•kg, 8.7 ft•lb) • Nut (wheel axle) "1" Nut (wheel axle): 105 Nm (10.5 m•kg, 75 ft•lb) Do not strike the inner race of the bearing. Contact should be made only with the outer race. Tighten the bolts in stage, using a crisscross pattern. 7. Tighten: • Bolt (axle holder) "1" 3. Install: • Collar "1" • Apply the lithium soap base grease on the oil seal lip. • Install the collars with their projections "a" facing the wheel.
FRONT WHEEL AND REAR WHEEL 4. Install: • Collar "1" Temporarily tighten the nut (wheel axle) at this point. Apply the lithium soap base grease on the oil seal lip. 9. Adjust: • Drive chain slack "a" 5. Install: • Wheel Install the brake disc "1" between the brake pads "2" correctly. 6. Install: • Drive chain "1" Push the wheel "2" forward and install the drive chain. Drive chain slack: 48–58 mm (1.9–2.3 in) Refer to "ADJUSTING THE DRIVE CHAIN SLACK" section in the CHAPTER 3. 10.
FRONT BRAKE AND REAR BRAKE FRONT BRAKE AND REAR BRAKE REMOVING THE FRONT BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Drain the brake fluid. Refer to removal section. 1 Brake hose holder (protector) 2 2 Union bolt 2 3 Brake hose 1 4 Pad pin plug 1 Remove when loosening the pad pin. 5 Pad pin 1 Loosen when disassembling the brake caliper.
FRONT BRAKE AND REAR BRAKE REMOVING THE REAR BRAKE Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Rear wheel Refer to "FRONT WHEEL AND REAR WHEEL" section. Drain the brake fluid. Refer to removal section. 1 Brake pedal 1 2 Brake master cylinder 1 3 Brake hose holder 2 4 Union bolt 2 5 Brake hose 1 6 Pad pin plug 1 Remove when loosening the pad pin.
FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE CALIPER Order Part name Q'ty Remarks A. B. Front Rear A B 1 Pad pin 1 1 2 Brake pad 2 2 3 Pad support 1 1 4 Brake caliper piston 2 1 Refer to removal section. 5 Brake caliper piston dust seal 2 1 Refer to removal section. 6 Brake caliper piston seal 2 1 Refer to removal section.
FRONT BRAKE AND REAR BRAKE DISASSEMBLING THE BRAKE MASTER CYLINDER Order Part name Q'ty Remarks A. B. 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 7 Washer 1 8 Push rod (Rear) 1 9 Brake master cylinder kit 1 5-9 Front Rear Use a long nose circlip pliers.
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. • Cover piston with rag and use extreme caution when expelling piston from cylinder. • Never attempt to pry out piston. Caliper piston removal steps: a. Insert a piece of rag into the brake caliper to lock one brake caliper. b.
FRONT BRAKE AND REAR BRAKE seals and brake caliper piston dust seals whenever a caliper is disassembled. CHECKING THE BRAKE CALIPER 1. Inspect: • Brake caliper cylinder inner surface "a" Wear/score marks → Replace brake caliper assembly. INSTALLING THE BRAKE CALIPER PISTON 1. Clean: • Brake caliper • Brake caliper piston seal • Brake caliper piston dust seal • Brake caliper piston Clean them with brake fluid. 2.
FRONT BRAKE AND REAR BRAKE 4. • • • • • • INSTALLING THE REAR BRAKE CALIPER 1. Install: • Pad support "1" • Brake pad "2" • Pad pin "3" • Install the brake pads with their projections "a" into the brake caliper recesses "b". • Temporarily tighten the pad pin at this point. INSTALLING THE BRAKE MASTER CYLINDER KIT 1. Clean: • Brake master cylinder • Brake master cylinder kit Clean them with brake fluid. 2.
FRONT BRAKE AND REAR BRAKE • Brake lever "1" • Bolt (brake lever) "2" • Bolt (brake master cylinder) "2" Bolt (brake master cylinder): 10 Nm (1.0 m•kg, 7.2 ft•lb) Bolt (brake lever): 6 Nm (0.6 m•kg, 4.3 ft•lb) • Nut (brake lever) "3" 3. • • • • Install: Spring "1" Brake pedal "2" O-ring "3" Bolt (brake pedal) "4" Bolt (brake pedal): 26 Nm (2.6 m•kg, 19 ft•lb) INSTALLING THE REAR BRAKE MASTER CYLINDER 1. Install: • Copper washer "1" • Brake hose "2" • Union bolt "3" Union bolt: 30 Nm (3.
FRONT BRAKE AND REAR BRAKE • Union bolt "3" lower the boiling point of the fluid and may result in vapor lock. Union bolt: 30 Nm (3.0 m•kg, 22 ft•lb) Brake fluid may erode painted surfaces or plastic parts. Always clean up spilled fluid immediately. Always use new copper washers. 2. Install: • Brake hose holder "1" • Screw (brake hose holder) "2" Screw (brake hose holder): 2 Nm (0.2 m•kg, 1.
FRONT BRAKE AND REAR BRAKE A. Front B. Rear 5. Install: (rear brake only) • Protector "1" • Bolt (protector) "2" Bolt (protector): 7 Nm (0.7 m•kg, 5.
FRONT FORK FRONT FORK REMOVING THE FRONT FORK 21 Nm (2.1 m kg, 15 ft lb) 21 Nm (2.1 m kg, 15 ft lb) 7 Nm (0.7 m kg, 5.1 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) 5 Nm (0.5 m kg, 3.6 ft lb) Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Front wheel Refer to "FRONT WHEEL AND REAR WHEEL" section. Front brake caliper Refer to "FRONT BRAKE AND REAR BRAKE" section.
FRONT FORK DISASSEMBLING THE FRONT FORK 30 Nm (3.0 m kg, 22 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 1 Nm (0.1 m kg, 0.7 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 55 Nm (5.5 m kg, 40 ft lb) Order Part name Q'ty Remarks 1 Adjuster 1 Drain the fork oil. Refer to removal section. 2 Fork spring 1 Drain the fork oil. 3 Dust seal 1 Refer to removal section. 4 Stopper ring 1 Refer to removal section. 5 Inner tube 1 Refer to removal section.
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 maintained at the dealers. To prevent an accidental explosion of air, the following instructions should be observed: The front fork with a built-in piston rod has a very sophisticated internal construction and is particularly sensitive to foreign material.
FRONT FORK Contamination → Clean. • O-ring "2" Wear/damage → Replace. • Piston metal "3" Wear/damage → Replace. • Spring "4" Damage/fatigue → Replace base valve. • Air bleed screw "5" Wear/damage → Replace. 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. half of the dial gauge reading. Do not attempt to straighten a bent inner tube as this may dangerously weaken the tube. 4.
FRONT FORK • • • • 7. Loosen: • Compression damping adjuster "1" 11. After filling, pump the damper assembly "1" slowly up and down more than 10 times to distribute the fork oil. • Loosen the compression damping adjuster finger tight. • Record the set position of the adjuster (the amount of turning out the fully turned in position). Stopper ring "2" Oil seal "3" Oil seal washer "4" Slide metal "5" To inner tube "6". • Apply the fork oil on the inner tube.
FRONT FORK vertically, the damper assembly may fall into it, damaging the valve inside. Fork seal driver: YM-A0948/90890-01502 22. Check: • Inner tube smooth movement Tightness/binding/rough spots → Repeat the steps 15 to 21. 19. Install: • Oil seal "1" Press the oil seal into the outer tube with fork seal driver "2". Fork seal driver: YM-A0948/90890-01502 • Loosen the rebound damping adjuster finger tight.
FRONT FORK If the adjuster is installed out of specification, proper damping force cannot be obtained. 29. Tighten: • Adjuster (locknut) "1" Adjuster (locknut): 29 Nm (2.9 m•kg, 21 ft•lb) Never fail to make the oil amount adjustment between the maximum and minimum amount and always adjust each front fork to the same setting. Uneven adjustment can cause poor handling and loss of stability. • Be sure to use recommended fork oil.
FRONT FORK 5. Install: • Protector "1" • Bolt (protector) "2" Bolt (protector): 5 Nm (0.5 m•kg, 3.6 ft•lb) 6. Adjust: • Rebound damping force Turn in the damping adjuster "1" finger-tight and then turn out to the originally set position. 7. Adjust: • Compression damping force Turn in the damping adjuster "1" finger-tight and then turn out to the originally set position.
HANDLEBAR HANDLEBAR REMOVING THE HANDLEBAR 1 Nm (0.1 m kg, 0.7 ft lb) 9 Nm (0.9 m kg, 6.5 ft lb) 28 Nm (2.8 m kg, 20 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) 40 Nm (4.0 m kg, 29 ft lb) 4 Nm (0.4 m kg, 2.9 ft lb) Order Part name Q'ty Number plate Remarks Remove the band only. 1 Clutch cable 1 2 Clutch lever holder 1 3 Engine stop switch 1 4 Brake master cylinder 1 5 Throttle cable cap 1 Turn over the cap cover.
HANDLEBAR DISASSEMBLING THE THROTTLE Order Part name Q'ty 1 Grip cap (lower) 1 2 Grip cap (upper) 1 3 Grip assembly 1 4 Grip (right) 1 5 Tube guide 1 5-25 Remarks Refer to removal section.
HANDLEBAR REMOVING THE BRAKE MASTER CYLINDER 1. Remove: • Brake master cylinder bracket "1" • Brake master cylinder "2" surface "a" with a lacquer thinner. • Align the mating mark "b" on the grip (right) with the slot "c" in the tube guide. • 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. 2.
HANDLEBAR 6. Install: • Throttle cables "1" To tube guide "2". Apply the lithium soap base grease on the throttle cable end and tube guide cable winding portion. 3. Tighten: • Nut (handlebar lower holder) "1" 11. Install: • Brake master cylinder "1" • Brake master cylinder bracket "2" • Bolt (brake master cylinder bracket) "3" Nut (handlebar lower holder): 40 Nm (4.0 m•kg, 29 ft•lb) Bolt (brake master cylinder bracket): 9 Nm (0.9 m•kg, 6.5 ft•lb) 7. Install: • Roller "1" • Collar "2" 4.
HANDLEBAR 13. Install: • Engine stop switch "1" • Clutch lever holder "2" • Bolt (clutch lever holder) "3" Bolt (clutch lever holder): 4 Nm (0.4 m•kg, 2.9 ft•lb) • Clamp "4" • The engine stop switch, clutch lever holder and clamp should be installed according to the dimensions shown. • Pass the engine stop switch lead in the middle of the clutch lever holder. (0.55 in) 14. Install: • Clutch cable "1" Apply the lithium soap base grease on the clutch cable end. 15.
STEERING STEERING REMOVING THE STEERING Order Part name Q'ty Remarks TIGHTENING STEPS: • Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb) • Loosen it one turn. • Retighten it. 7 Nm (0.7 m•kg, 5.1 ft•lb) Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Number plate Refer to "SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 4. Handlebar Refer to "HANDLEBAR" section.
STEERING Order 9 Part name Q'ty Bearing race 2 5-30 Remarks Refer to removal section.
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". Steering nut wrench: YU-33975/90890-01403 Support the steering stem so that it may not fall down. CHECKING THE BEARING AND BEARING RACE 1. Wash the bearings and bearing races with a solvent. 2. Inspect: • Bearing "1" • Bearing race Pitting/damage → Replace bearings and bearing races as a set.
STEERING 6. Install: • Washer "1" 11. Tighten: • Pinch bolt (upper bracket) "1" Pinch bolt (upper bracket): 21 Nm (2.1 m•kg, 15 ft•lb) • Pinch bolt (lower bracket) "2" 7. Install: • Front fork "1" • Upper bracket "2" • Temporarily tighten the pinch bolts (lower bracket). • Do not tighten the pinch bolts (upper bracket) yet. Pinch bolt (lower bracket): 21 Nm (2.1 m•kg, 15 ft•lb) Tighten the lower bracket to specified torque. If torqued too much, it may cause the front fork to malfunction. 8.
SWINGARM SWINGARM REMOVING THE SWINGARM Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Brake hose holder Refer to "FRONT BRAKE AND REAR BRAKE" section. Rear brake caliper Refer to "FRONT BRAKE AND REAR BRAKE" section. Bolt (brake pedal) Shift the brake pedal backward.
SWINGARM DISASSEMBLING THE SWINGARM 70 Nm (7.0 m kg, 50 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 6 Nm (0.6 m kg, 4.3 ft lb) 80 Nm (8.0 m kg, 58 ft lb) Order Part name Q'ty 1 Cap 2 2 Relay arm 1 3 Connecting rod 1 4 Collar 2 5 Oil seal 2 6 Thrust bearing 2 7 Bushing 2 8 Oil seal 8 9 Bearing 10 5-34 Remarks Refer to removal section. Refer to removal section.
SWINGARM HANDLING NOTE Damage → Replace. Support the machine securely so there is no danger of it falling over. REMOVING THE CAP 1. Remove: • Left cap "1" Remove with a slotted-head screwdriver inserted under the mark "a" on the left cap. CHECKING THE CONNECTING ROD 1. Inspect: • Bearing "1" • Collar "2" Free play exists/unsmooth revolution/rust → Replace bearing and collar as a set. 2. Inspect: • Oil seal "3" Damage → Replace. REMOVING THE BEARING 1. Remove: • Bearing "1" 2.
SWINGARM • Washer "3" • Nut (connecting rod) "4" Nut (connecting rod): 80 Nm (8.0 m•kg, 58 ft•lb) • Swingarm up and down movement "b" Unsmooth movement/binding/ rough spots → Grease or replace bearings, bushings and collars. To relay arm "5". INSTALLING THE SWINGARM 1. Install: • Bushing "1" • Thrust bearing "2" • Oil seal "3" • Collar "4" To swingarm "5". Apply the molybdenum disulfide grease on the bushings, thrust bearings, oil seal lips and contact surfaces of the collar and thrust bearing. 2.
SWINGARM • Nut (drive chain support) "4" Nut (drive chain support): 7 Nm (0.7 m•kg, 5.1 ft•lb) • Bolt {drive chain support cover [L = 10 mm (0.39 in)]} "5" 11. Tighten: • Nut (relay arm) "1" Nut (relay arm): 70 Nm (7.0 m•kg, 50 ft•lb) Bolt (drive chain support cover): 7 Nm (0.7 m•kg, 5.1 ft•lb) 12. Install: • Cap "1" Install the right cap with its mark "a" facing forward. 13.
REAR SHOCK ABSORBER REAR SHOCK ABSORBER REMOVING THE REAR SHOCK ABSORBER 56 Nm (5.6 m kg, 40 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 32 Nm (3.2 m kg, 23 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 53 Nm (5.3 m kg, 38 ft lb) Order Part name Q'ty Remarks Hold the machine by placing the suitable stand under the engine. Refer to "HANDLING NOTE". Seat Refer to "SEAT, FUEL TANK AND SIDE COVERS" section in the CHAPTER 4. Silencer Refer to "EXHAUST PIPE AND SILENCER" section in the CHAPTER 4.
REAR SHOCK ABSORBER 56 Nm (5.6 m kg, 40 ft lb) 2 Nm (0.2 m kg, 1.4 ft lb) 32 Nm (3.2 m kg, 23 ft lb) 29 Nm (2.9 m kg, 21 ft lb) 53 Nm (5.3 m kg, 38 ft lb) Order 12 Part name Q'ty Bearing 2 5-39 Remarks Refer to removal section.
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-pressure nitrogen gas. To prevent the danger of explosion, read and understand the following information before handling the shock absorber. The manufacturer can not be held responsible for property damage or personal injury that may result from improper handling.
REAR SHOCK ABSORBER 3. Install: • Lower bearing "1" Install the bearing by pressing it on the side having the manufacture's marks or numbers. Installed depth of the bearing "a": 4 mm (0.16 in) INSTALLING THE SPRING (REAR SHOCK ABSORBER) 1. Install: • Spring "1" • Upper spring guide "2" • Lower spring guide "3" 4. Adjust: • Spring length (installed) Refer to "ADJUSTING THE REAR SHOCK ABSORBER SPRING PRELOAD" section in the CHAPTER 3. 5.
REAR SHOCK ABSORBER • Bolt [rear frame (lower)] "3" Bolt [rear frame (lower)]: 29 Nm (2.9 m•kg, 21 ft•lb) 7. Tighten: • Bolt (air filter joint) "1" Bolt (air filter joint): 2 Nm (0.2 m•kg, 1.
ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL ELECTRICAL COMPONENTS AND WIRING DIAGRAM ELECTRICAL COMPONENTS 1. 2. Engine stop switch CDI unit 3. 4. Ignition coil CDI magneto 5. Spark plug WIRING DIAGRAM 1. 2. 3. 4. 5.
IGNITION SYSTEM IGNITION SYSTEM INSPECTION STEPS Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure and for checking the spark plug which will not spark. Spark gap test Spark No spark No good → Replace. No good → No good → No good → Replace. Replace. ↓ Check CDI magneto. (pickup coil and charging coil) OK Repair or replace. ↓ Check spark plug cap. OK → ↓ Check ignition coil.
IGNITION SYSTEM SPARK GAP TEST 1. Disconnect the spark plug cap from spark plug. 2. Connect the dynamic spark tester "1" (ignition checker "2") as shown. • Ignition coil "3" • Spark plug "4" Not conductive while it is pushed → Replace. Conductive while it is freed → Replace. Set the tester selection position to "Ω × 1". CHECKING THE IGNITION COIL 1. Inspect: • Primary coil resistance Out of specification → Replace. Tester (+) lead → Yellow lead "1" Tester (-) lead → Black lead "2" A. For USA and CDN B.
IGNITION SYSTEM 2. Inspect: • Charging coil 1 resistance Out of specification → Replace. Tester (+) lead → Black/Red lead "1" Tester (-) lead → Green/White lead "2" Charging Tester secoil 1 resis- lector positance tion 720–1,080 Ω at 20 °C Ω × 100 (68 °F) 3. Inspect: • Charging coil 2 resistance Out of specification → Replace.
ENGINE TUNING ENGINE CARBURETOR SETTING • The role of fuel is to cool the engine, and in the case of a 2-stroke engine, to lubricate the engine in addition to power generation. Accordingly, if a mixture of air and fuel is too lean, abnormal combustion will occur, and engine seizure may result. If the mixture is too rich, spark plugs will get wet with oil, thus making it impossible to bring the engine into full play or if the worst comes to the worst, the engine may stall.
ENGINE ADJUSTING THE PILOT JET The richness of air-fuel mixture with the throttle fully closed to 1/2 open can be set by changing the pilot jet "1". It is changed when adjustment cannot be made by the pilot air screw alone. Standard pilot jet #40 *#45 *For EUROPE ADJUSTING THE JET NEEDLE (For USA and CDN) On the carburetors used in the YZ125, the main nozzle is a non disassembly type, so it can not be replaced. Therefore, carburetor setting requires the change of the jet needle. 1.
ENGINE *** For AUS, NZ and ZA 6BFY42-74-3 6BFY42-74-2 6BFY42-75-3 Jet needle "4" (For EUROPE, AUS, NZ and ZA) 6BFY43-74-3 6BFY43-74-2 6BFY43-75-3 A. Lean (larger diameter) B. Rich (smaller diameter) C. 1st taper D. 2nd taper E. 3rd taper F. 4th taper 1. Full closed 2. 1/4 throttle 3. 1/2 throttle 4. 3/4 throttle 5. Full open a.
ENGINE ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING General condition Main jet Jet needle Pilot jet Sandy condition Under 10°C (50°F) 15–25°C (59– 77°F) Over 30°C (86°F) Under 10°C (50°F) 15–25°C (59– 77°F) Over 30°C (86°F (Winter) (Spring, Autumn) (Summer) (Winter) (Spring, Autumn) (Summer) A #420 #410 #410 #440 #430 #430 B, C #440 #430 #420 #460 #450 #440 A 6BFY43-74-3 6BFY42-74-3 6BFY42-74-3 6BFY43-74-4 6BFY42-74-4 6BFY43-74-3 B, C 6BFY44-74-3 6BFY43-74-3 6BFY4
ENGINE Symptom At full throttle Stop of speed pick-up Slow speed pick-up Slow response Sooty spark plug ↓ Rich mixture Lean mixture Rich mixture 1/4–3/4 throttle *Hard breathing Lack of speed Setting Checking Decrease main jet calibration no. (Gradual- Discoloration of spark plug → If tan color, it is in good condition. ly) *In case of racing slight enrichment of mix- If not effect: Clogged air filter ture reduces engine trouble.
CHASSIS CHANGE OF THE HEAT RANGE OF SPARK PLUGS Judging from the discoloration of spark plugs, if they are found improper, it can be corrected by the following two methods; changing carburetor settings and changing the heat range of spark plug. Standard spark plug BR9EVX/NGK (resistance type) • In principle, it is advisable to first use spark plugs of standard heat range, and judging from the discoloration of spark plugs, adjust carburetor settings. • If the calibration No.
CHASSIS Turn in one or two clicks. Adjust the oil amount in 5 cm3 (0.2 Imp oz, 0.2 US oz) increments or decrements. Too small oil amount causes the front fork to produce a noise at full rebound or the rider to feel some pressure on his hands or body. Alternatively, too large oil amount will cause the air spring characteristics to have a tendency to be stiffer with the consequent deteriorated performance and characteristics. Therefore, adjust the front fork within the specified range.
CHASSIS set length, replace the spring with an optional one and make readjustment. REAR SHOCK ABSORBER SETTING PARTS • Rear shock spring "1" [Equal-pitch titanium spring] T Y P E SETTING OF SPRING AFTER REPLACEMENT After replacement, be sure to adjust the spring to the set length [sunken length 90–100 mm (3.5–3.9 in)] and set it. 1. Use of soft spring • Set the soft spring for less rebound damping to compensate for its less spring load.
CHASSIS • Extent of adjustment (spring length) [Titanium spring] SPRING FREE LENGTH EXTENT OF ADJUSTMENT "b" One I.D. mark 245.5–263.5 mm (9.67–10.37 in) Approx. 265 mm (10.43 in) Two I.D. marks 251.5–269.5 mm (9.90–10.61 in) Three I.D. marks 243.0–261.0 mm (9.57–10.28 in) [Steel spring] SPRING FREE LENGTH EXTENT OF ADJUSTMENT "b" 260 mm (10.24 in) 240.5–258.5 mm (9.47–10.18 in) 275 mm (10.83 in) 255.5–273.5 mm (10.06–10.
CHASSIS SUSPENSION SETTING (FRONT FORK) • If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure given in the same chart. • Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm (3.5–3.9 in).
CHASSIS SUSPENSION SETTING (REAR SHOCK ABSORBER) • If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure given in the same chart. • Adjust the rebound damping in 2-click increments or decrements. • Adjust the low compression damping in 1-click increments or decrements. • Adjust the high compression damping in 1/6 turn increments or decrements.
PRINTED ON RECYCLED PAPER YAMAHA MOTOR CO., LTD.
