Segment:
High-performance off-road motorcycle, often used for competitive trail riding and enduro.
Competitors:
KTM EXC series, Honda CRF-X series, Kawasaki KX-FX series, Suzuki RM-Z (off-road variants).
Engine Type:
Liquid-cooled, four-stroke, single-cylinder (specific displacement likely 250cc).
Suspension Type:
High-quality upside-down front forks and monoshock rear suspension, designed for off-road terrain.
Engine Overhaul:
Complete disassembly, inspection, repair, and reassembly of engine components.
Fuel System:
Carburetor (model dependent), fuel lines, fuel tank, fuel pump (if applicable).
Ignition System:
CDI unit, ignition coil, spark plug, wiring.
Lubrication System:
Oil pump, oil filter, oil passages, oil specifications.
Cooling System:
Radiator, hoses, thermostat, coolant specifications (if liquid-cooled).
Transmission And Clutch:
Clutch operation, disassembly, inspection, repair; transmission gear inspection, maintenance.
Suspension:
Front fork (KYB USD type likely), rear shock absorber, linkage, adjustment, seal replacement.
Brakes:
Front and rear brake systems (hydraulic disc), caliper maintenance, pad replacement, fluid flush, master cylinder service.
Electrical System:
Wiring diagrams, lighting, battery maintenance, starter system, fuses, switches.
Chassis And Frame:
Frame inspection, steering head bearing service, wheel bearing maintenance, spoke tensioning.
Bodywork And Plastics:
Fairing removal/installation, seat, fenders.
Preventive Maintenance:
Regular inspection and service tasks, fluid changes, filter replacements.
Troubleshooting:
Diagnosis of common problems, symptom-based troubleshooting guides.
Disassembly And Assembly:
Step-by-step instructions for removing and reinstalling all major components.
Adjustments:
Carburetor tuning, suspension settings, chain slack, clutch and brake lever adjustments.
Special Tool Usage:
Identification and illustrated use of specialized tools required for specific repairs.
Depth:
Comprehensive, covering everything from basic maintenance to complete engine rebuilds and chassis work.
Target Audience:
Professional mechanics and experienced DIY enthusiasts.
Engine Type:
Liquid-cooled, four-stroke, DOHC, single-cylinder
Displacement:
Approximately 250cc (specific model variants may differ slightly in bore/stroke).
Bore X Stroke:
To be specified in manual, typical for this era around 70mm x 64.5mm (example, actual values are critical).
Compression Ratio:
Typically high for performance, e.g., 12.5:1 to 13.5:1.
Horsepower:
Estimated 30-35 HP (at crank, specific dyno charts vary).
Torque:
Estimated 20-24 lb-ft (at crank, specific dyno charts vary).
Carburetor Type:
Keihin FCR flat-slide carburetor (e.g., FCR37 or FCR39).
Fuel Capacity:
Typically 2.5-3.5 gallons for extended off-road use.
Length:
To be specified in manual, typical for dirt bikes ~2150mm.
Width:
To be specified in manual, typical for dirt bikes ~800mm.
Height:
To be specified in manual, typical for dirt bikes ~1250mm.
Dry Weight:
Approximately 240-250 lbs (109-113 kg).
Wet Weight:
To be specified in manual, typically ~255-265 lbs with fluids.
Ground Clearance:
Typically high, >300mm.
Oil Change Interval:
Every 10-15 riding hours or 1000 km (refer to manual for specific intervals).
Air Filter Cleaning:
Every 5-10 riding hours or as needed based on conditions.
Valve Clearance Check:
Every 20-30 riding hours or annually.
Spark Plug Replacement:
Every 20-30 riding hours or as needed.
Engine Oil Type:
Yamalube 4 (or equivalent) SAE 10W-30, 10W-40, or 20W-40 API SG or higher.
Engine Oil Capacity:
Approximately 0.7-0.8 liters (refer to manual for exact capacity).
Brake Fluid Type:
DOT 4 hydraulic brake fluid.
Coolant Type:
High-quality ethylene glycol-based antifreeze coolant (50% mixture with distilled water).
Common Wear Items:
Clutch plates, wheel bearings, steering head bearings, fork seals, chain and sprockets, exhaust packing.
Typical Trouble Spots:
Carburetor jetting (can be sensitive to altitude/temperature), kickstart mechanism, occasional stator issues.
Heritage:
Yamaha has a long and successful history in motocross and off-road racing with models like the YZ series, transferring technology and expertise to the WR line.
Evolution Points:
This generation of WR250 was a key model in Yamaha's off-road lineup, focusing on reliable performance for trail riding and competition, often derived from the YZ platform but with features tailored for durability and broader usability.
Production Period:
2000-2009 for this specific manual's coverage.
