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General| Displacement | 250cc |
|---|---|
| Bore x Stroke | 77.0mm x 53.6mm |
| Compression Ratio | 13.5:1 |
| Ignition | CDI |
| Transmission | 5-speed |
| Final Drive | Chain |
| Front Tire | 80/100-21 |
| Rear Tire | 100/90-19 |
| Fuel Delivery | Carburetor |
| Front Brake | Hydraulic single disc |
| Rear Brake | Hydraulic single disc |
| Wheelbase | 58.1 in |
| Fuel Capacity | 1.8 gal |
| Engine Type | 4-stroke, liquid-cooled, DOHC, 5-valve |
| Seat Height | 965 mm (38.0 in) |
| Curb Weight | 102 kg (225 lb) |
Overview of the manual and congratulations on the purchase.
Important safety warnings regarding operation and maintenance.
Machine is for competition use only on closed courses.
Alerts to potential hazards and safety warnings.
Guidance on locating specific information within the manual.
Explanation of the manual's structure and notation.
Explanation of symbols used in diagrams for specifications and lubrication.
Provides an overview of the machine's main components.
Location and importance of the VIN.
Location of the engine's unique serial number.
Location of the model identification label.
Lists detachable sidestand and tools like spark plug wrench.
Steps for preparing the machine before disassembly.
Inspection and installation of circlips.
Guidelines for using genuine Yamaha parts and recommended lubricants.
Guidelines for replacing gaskets, oil seals, and O-rings.
Rules for replacing lock washers, plates, and cotter pins.
Instructions for installing bearings and oil seals.
Tool for removing the crankshaft from the crankcase.
Tool used to remove the flywheel magneto.
Tool for loosening/tightening flywheel magneto nut.
Tools for checking runout or bent parts.
Tools for installing the crankshaft.
Tool for removing the piston pin.
Tools for checking the cooling system, including radiator cap.
Tool for tightening the steering ring nut.
Tool for loosening/tightening base valve.
Tool for loosening/tightening damper assembly.
Tool for installing fork oil seals.
Instrument for inspecting ignition system components.
Tool necessary for checking ignition timing.
Tool for removing/installing valve assemblies.
Tool for holding the clutch when removing/installing clutch boss nut.
Tool for removing and installing valve guides.
Tool for installing valve guides.
Tool for reboring new valve guides.
Instrument for checking ignition system components.
Instrument for checking ignition system components.
Sealant used for crankcase mating surfaces.
Left handlebar switch to stop the engine.
Left handlebar lever to engage/disengage the clutch.
Left side pedal for shifting gears.
Lever to start the engine manually.
Right handlebar grip to control engine speed.
Right handlebar lever to activate the front brake.
Right side pedal to activate the rear brake.
Controls fuel flow to the carburetor.
Enriches air-fuel mixture for cold starting.
Assists starting a warm engine.
Specifies premium unleaded gasoline with 95 octane or higher.
Step-by-step procedure for starting a cold engine.
Procedure for starting a warm or recently stopped engine.
Steps for restarting the engine after it stalls.
Troubleshooting steps for a non-starting engine.
Recommended steps for breaking in the new machine.
Identifies parts that need break-in after replacement.
Torque specifications for frame-related fasteners.
Torque specifications for exhaust system components.
Torque specifications for engine mounting bolts.
Torque specifications for steering components.
Torque specifications for front and rear suspension parts.
Torque specifications for wheel axle and related parts.
Torque specifications for brake system components.
Torque specification for fuel tank to fuel cock connection.
Torque specification for oil hose clamp.
Detailed steps for washing the machine.
Preventive measures for storing the machine for 60 days or more.
Key dimensions, engine type, displacement, and starting system details.
Details on fuel type, tank capacity, and carburetor model.
Specifications for transmission type, gear ratios, frame type, and caster angle.
Details on brake types, suspension systems, and shock absorbers.
Specifications for cylinder head warp limit.
Specifications for cylinder bore size and out-of-round limit.
Specifications for camshaft dimensions and runout.
Specifications for valve clearance, dimensions, and stem-to-guide clearance.
Specifications for valve spring free length and compressed force.
Specifications for piston-to-cylinder clearance and piston size.
Specifications for piston ring end gap and side clearance.
Specifications for crankshaft width and runout limit.
Specifications for clutch friction plate thickness and quantity.
Specifications for clutch quantity and warp limit.
Specifications for clutch spring free length and housing clearances.
Specifications for shifter type and guide bar bending limit.
Specifications for kickstarter type and carburetor details.
Detailed specifications for carburetor jets and settings.
Specifications for oil filter type, oil pump, and clearances.
Specifications for radiator core size.
Specifications for radiator height, thickness, capacity, and water pump.
Specifications for steering bearing type.
Specifications for front fork travel, spring free length, and oil.
Specifications for shock absorber travel and spring free length.
Specifications for swingarm free play limit.
Specifications for front wheel type and rim dimensions.
Specifications for drive chain type, links, and slack.
Specifications for front brake disc dimensions and pad thickness.
Torque specifications for engine fasteners and components.
Torque specifications for engine fasteners and components.
Torque specs for steering, brakes, and front fork components.
Torque specs for engine mounting, frame, fuel tank, and fenders.
Torque specifications for electrical components.
Glossary of units used in torque specifications.
Diagram illustrating the engine's oil circulation system.
Diagram showing oil flow to the crankshaft and oil pump.
Illustrates the routing of various cables and hoses around the frame.
Details cable routing for clutch, fuel, and breather hoses.
Shows routing for hot starter, radiator, and neutral switch leads.
Details routing for neutral switch, CDI leads, and radiator hoses.
Illustrates routing for throttle cables and ignition coil lead.
Shows proper routing and positioning of brake hoses.
Illustrates routing for throttle, clutch, and starter cables at the handlebar.
Schedule for engine oil replacement and valve inspection/adjustment.
Schedule for piston inspection/cleaning and cylinder head inspection.
Maintenance intervals for cylinder, clutch, and transmission components.
Maintenance intervals for crank, carburetor, and spark plug checks.
Maintenance intervals for drive chain lubrication and cooling system checks.
Maintenance intervals for air filter cleaning/replacement and oil filter replacement.
Maintenance intervals for frame, fuel tank, and brake system checks.
Maintenance intervals for front forks and rear shock absorber.
Maintenance intervals for swingarm and steering head.
Maintenance intervals for tire pressure, wheel checks, and drive chain lubrication.
Maintenance intervals for throttle/control cables and starter/clutch levers.
Checklist for pre-ride inspection of coolant, fuel, oil, brakes, wheels, and steering.
Procedure for checking and refilling engine coolant.
Steps for draining, flushing, and refilling the cooling system.
Inspection of the radiator cap's seal, valve, and deposits.
Procedure for checking radiator cap opening pressure.
Steps to check and adjust clutch lever free play.
Steps to check and adjust throttle grip free play.
Steps to check and adjust hot starter lever free play.
Procedure for cleaning and maintaining the air filter element.
Procedure for checking the engine oil level.
Steps for changing the engine oil and oil filter.
Procedure for adjusting the pilot screw for optimal fuel flow.
Procedure for adjusting engine idling speed.
Procedure for checking and adjusting valve clearance.
Steps for installing camshafts after valve clearance adjustment.
Table for adjusting intake valve clearance.
Table for adjusting exhaust valve clearance.
Procedure for bleeding air from the hydraulic brake system.
Procedure for adjusting the front brake lever position.
Procedure for adjusting the rear brake pedal height.
Procedure for inspecting and replacing front brake pads.
Procedure for inspecting and replacing rear brake pads.
Procedure for checking and refilling brake fluid.
Inspection of sprocket teeth for wear.
Procedure for measuring and checking drive chain length and stiffness.
Procedure for adjusting drive chain slack.
Inspect front fork smooth action and check for oil leakage.
Procedure for cleaning fork oil and dust seals.
Procedure to relieve internal pressure in the front fork.
Procedure to adjust front fork rebound damping.
Procedure to adjust front fork compression damping.
Inspect rear shock absorber for smooth action and damage.
Procedure to adjust rear shock absorber spring preload.
Procedure to adjust rear shock absorber rebound damping.
Procedure to adjust rear shock absorber low compression damping.
Procedure to adjust rear shock absorber high compression damping.
Procedure to measure and adjust tire pressure.
Inspect and tighten spokes for looseness.
Inspect wheel runout and bearing free play.
Check steering stem for smooth action and adjust steering head.
Procedure for adjusting the steering ring nut.
Lubrication points for smooth operation of components.
Procedure for inspecting and cleaning the spark plug.
Procedure for checking and adjusting ignition timing.
Exploded view and parts list for removing seat, fuel tank, and side covers.
Procedure for removing the side cover.
Procedure for removing the number plate.
Procedure for installing the air scoop.
Exploded view and parts list for removing exhaust pipe and silencer.
Inspect the gasket for damage.
Procedure for replacing the silencer fiber.
Procedure for installing the silencer and exhaust pipe.
Exploded view and parts list for removing the radiator.
Inspect the radiator core for obstructions and bent fins.
Procedure for installing the radiator and associated hoses.
Exploded view and parts list for removing the carburetor assembly.
Exploded view and parts list for disassembling the carburetor.
Exploded view and parts list for disassembling the carburetor.
Inspect needle valve, valve seat, and filter.
Check throttle valve for free movement.
Inspect jet needle, clip groove, and clip position.
Procedure for measuring and adjusting float height.
Inspect the float for damage.
Inspect starter plunger for wear or damage.
Inspect accelerator pump components.
Steps for installing carburetor components.
Steps for installing various carburetor parts and assemblies.
Procedure for adjusting the accelerator pump timing.
Procedure for installing the carburetor assembly.
Exploded view and parts list for removing the cylinder head cover.
Exploded view and parts list for removing the camshafts.
Procedure for removing camshafts and timing chain components.
Inspect camshaft lobes and measure dimensions.
Inspect camshaft sprocket for wear.
Check the decompression mechanism.
Check the timing chain tensioner operation.
Procedure for installing camshafts.
Procedure for installing shift guide and lever assembly.
Procedure for installing kick shaft assembly.
Exploded view and parts list for removing the cylinder head.
Procedure for checking cylinder head for carbon deposits and warpage.
Procedure for installing the cylinder head.
Exploded view and parts list for removing valves and springs.
Procedure for removing valve lifters and valve cotters.
Check valve sealing and replace valve guides.
Measure margin thickness, runout, and valve seat width.
Measure valve spring free length.
Procedure for installing valves, springs, and lifters.
Inspect valve lifters for scratches or damage.
Exploded view and parts list for removing the cylinder and piston.
Procedure for removing piston pin, clips, and piston rings.
Inspect cylinder/piston walls and measure clearance.
Measure piston ring side clearance.
Inspect and measure piston pin-to-piston clearance.
Procedure for installing piston rings and piston.
Procedure for installing the cylinder and gasket.
Procedure for installing the cylinder with timing chain.
Exploded view and parts list for removing the clutch assembly.
Exploded view and parts list for removing the clutch assembly.
Procedure for removing the clutch boss.
Inspect clutch housing and boss for wear or damage.
Check primary driven gear for play and wear.
Measure clutch spring free length.
Measure friction plate thickness.
Measure clutch plate warpage.
Inspect push lever shaft for wear or damage.
Inspect push rod, bearing, washer, and ball.
Procedure for installing push lever shaft.
Procedure for installing clutch components like gears, plates, springs, and cover.
Procedure for installing the clutch cover.
Exploded view and parts list for removing oil filter and water pump.
Exploded view and parts list for removing oil filter and water pump.
Procedure for removing the impeller shaft.
Procedure for removing the oil seal.
Inspect the oil delivery pipe for damage or blockage.
Inspect the impeller shaft for bends or wear.
Inspect impeller shaft gear teeth for wear.
Inspect the bearing for smooth rotation.
Inspect the oil seal for wear or damage.
Procedure for installing the oil seal.
Procedure for installing the bearing.
Procedure for installing the impeller shaft.
Procedure for installing the right crankcase cover.
Procedure for installing the kickstarter crank.
Procedure for installing the water pump housing.
Procedure for installing the oil filter element and cover.
Exploded view and parts list for removing the balancer.
Procedure for removing the balancer shaft and nuts.
Inspect gears for wear or damage.
Inspect the balancer shaft for cracks or damage.
Procedure for installing the balancer shaft and gears.
Exploded view and parts list for removing the oil pump assembly.
Exploded view and parts list for removing the rotor housing.
Exploded view and parts list for removing the oil tank.
Inspect and measure clearances of oil pump components.
Procedure for installing the oil pump assembly.
Exploded view and parts list for removing kick and shift shafts.
Exploded view and parts list for removing kick and shift shafts.
Procedure for removing the kick shaft assembly.
Procedure for removing shift guide and lever assembly.
Procedure for removing the segment.
Check kick shaft and ratchet wheel for smooth movement.
Inspect gears and teeth for wear.
Inspect shift shaft for bend or damage.
Inspect shift guide, lever, pawl, and spring.
Inspect stopper lever and spring.
Procedure for installing the segment.
Procedure for installing stopper lever.
Procedure for installing shift guide and lever assembly.
Procedure for installing shift shaft and related parts.
Procedure for installing kick shaft assembly.
Procedure for installing the kick idle gear.
Exploded view and parts list for removing the CDI magneto.
Procedure for removing the rotor using special tools.
Inspect rotor and stator surfaces for damage.
Inspect the Woodruff key for damage.
Procedure for installing the CDI magneto.
Exploded view and parts list for engine removal.
Exploded view and parts list for engine removal.
Procedure for removing the drive sprocket.
Procedure for removing the engine.
Procedure for installing the engine.
Procedure for installing the brake pedal.
Procedure for installing the drive sprocket.
Procedure for installing the neutral switch.
Exploded view and parts list for removing the crankshaft.
Exploded view and parts list for removing the crankshaft.
Procedure for removing crankcase bearings.
Procedure for separating the crankcase halves.
Procedure for removing the crankshaft.
Procedure for removing crankcase bearings.
Inspect timing chain and guide for wear.
Inspect crankcase mating surface and bearing.
Measure crankshaft runout and clearances.
Inspect oil strainer for damage.
Inspect oil delivery pipe for damage or blockage.
Procedure for installing crankcase bearings and stoppers.
Procedure for installing the crankshaft.
Procedure for installing crankcase halves.
Exploded view and parts list for transmission removal.
Procedure for removing transmission components.
Inspect gear teeth and grooves for wear.
Inspect bearing for smooth rotation.
Inspect shift fork, cam, and segment for wear.
Procedure for installing transmission gears and shafts.
Procedure for installing transmission assembly.
Exploded view and parts list for removing the front wheel.
Exploded view and parts list for removing the rear wheel.
Inspect wheel runout and bearing.
Measure wheel axle bends.
Measure brake disc deflection and thickness.
Procedure for installing the front wheel.
Procedure for installing front wheel components.
Procedure for installing the rear wheel.
Procedure for installing rear wheel components.
Exploded view and parts list for removing the front brake.
Exploded view and parts list for removing the rear brake.
Exploded view and parts list for disassembling the brake caliper.
Exploded view and parts list for disassembling the brake master cylinder.
Procedure for draining the brake fluid.
Procedure for removing the brake caliper piston.
Procedure for removing brake caliper piston seals and dust seals.
Inspect brake master cylinder inner surface and diaphragm.
Inspect brake caliper cylinder and piston for wear.
Inspect brake hose for cracks or damage.
Procedure for cleaning and installing brake caliper piston.
Procedure for installing the front brake caliper.
Procedure for installing the rear brake caliper.
Procedure for installing the brake master cylinder kit.
Procedure for installing the front brake master cylinder.
Procedure for installing brake caliper components.
Procedure for installing rear brake master cylinder.
Procedure for installing the front brake hose.
Procedure for installing the rear brake hose.
Procedure for filling and bleeding the brake fluid.
Procedure for installing the protector on the rear brake.
Exploded view and parts list for removing the front fork.
Exploded view and parts list for disassembling the front fork.
Procedure for removing the damper assembly.
Procedure for removing the adjuster.
Procedure for removing the inner tube.
Procedure for removing the base valve.
Inspect damper assembly and O-ring.
Inspect base valve, O-ring, piston metal, spring, and air bleed screw.
Inspect piston metal for wear.
Measure fork spring free length.
Inspect inner tube surface and bends.
Inspect outer tube for score marks or damage.
Inspect adjuster and O-ring.
Procedure for washing and filling front fork oil.
Procedure for assembling damper assembly and fork components.
Procedure for installing the front fork.
Procedure for installing the front fork.
Procedure to adjust compression damping force.
Exploded view and parts list for removing the handlebar.
Procedure for removing the brake master cylinder.
Procedure for removing the handlebar grip.
Inspect handlebar for bends or damage.
Procedure for installing the handlebar and holders.
Procedure for installing handlebar components like grips and cables.
Refer to Chapter 3 for clutch lever free play adjustment.
Refer to Chapter 3 for hot starter lever free play adjustment.
Exploded view and parts list for removing the steering system.
Exploded view and parts list for removing the steering system.
Procedure for removing the steering ring nut.
Procedure for removing the lower bearing.
Procedure for removing the bearing race.
Inspect steering stem for bend or damage.
Wash and inspect bearings and races.
Procedure for installing the lower bracket.
Procedure for installing steering components.
Exploded view and parts list for removing the swingarm.
Exploded view and parts list for disassembling the swingarm.
Procedure for removing the left cap.
Procedure for removing the bearing.
Inspect swingarm bearing and bushing.
Inspect relay arm bearing and collar.
Inspect connecting rod bearing and oil seal.
Procedure for installing bearings and oil seals.
Procedure for installing swingarm components.
Procedure for installing swingarm components.
Exploded view and parts list for removing the rear shock absorber.
Exploded view and parts list for removing the rear shock absorber.
Procedure for removing the bearing.
Inspect damper rod, spring, and seals.
Procedure for installing bearings.
Procedure for installing the spring.
Procedure for installing the rear shock absorber.
Lists and identifies key electrical components.
Diagram showing the electrical system connections.
Step-by-step guide for troubleshooting ignition system failures.
Procedure for testing spark plug gap and ignition spark.
Check connections and condition of ignition coil.
Inspect engine stop switch conduction.
Inspect primary and secondary coil resistance.
Inspect pickup coil and charging coil resistance.
Inspect neutral switch conduction.
Check CDI unit and electrical components for faults.
Troubleshooting steps if the throttle position sensor does not operate.
Check couplers and leads for rust, dust, or looseness.
Inspect throttle position sensor coil resistance.
Procedure for changing and adjusting the throttle position sensor.
Measure throttle position sensor input voltage.
Guidance on adjusting carburetor based on atmospheric conditions.
Explains how setting parts affect performance at different throttle openings.
Overview of carburetor construction and setting parts.
Explains how changing the main jet affects engine power.
Procedure for adjusting pilot screw for mixture control.
Procedure for adjusting pilot jet for mixture control.
Adjusting jet needle clip position for acceleration.
Adjusting jet needle for fuel mixture.
Table of main jets, pilot jets, jet needles, and leak jets.
Specifications for jet needle straight portion diameter.
Troubleshooting guide for carburetor settings based on symptoms.
Guidance on selecting the appropriate drive and rear wheel sprockets.
List of drive and rear wheel sprockets with part numbers.
Recommendations for adjusting tire pressure based on road surface.
Factors influencing front fork setting: spring characteristics, preload, damping.
Guidance on adjusting front fork based on symptoms.
Specifications for rear shock absorber springs.
Troubleshooting guide for front fork symptoms.
Troubleshooting guide for rear shock absorber symptoms.
