Target Audience:
Yamaha WR250 owners, mechanics, and parts suppliers seeking authentic OEM part information.
Value Proposition:
Provides cost savings on parts by enabling self-identification and sourcing, bypassing dealership markups.
Illustrations:
Extensive use of exploded parts diagrams for clear visual reference.
Part Numbers:
Comprehensive listing of all OEM part numbers for accurate procurement.
Usability:
Designed for ease of understanding, even for individuals with limited technical experience.
Engine Assembly:
Detailed breakdown of engine components, including cylinder, piston, crankshaft, camshaft, valves, and associated parts.
Fuel System:
Carburetor components, fuel tank, petcock, fuel lines, and related fittings.
Ignition System:
CDI unit, ignition coil, spark plug, wiring harness components related to ignition.
Cooling System:
Radiator, hoses, water pump components, thermostat (if applicable to the WR250 model).
Exhaust System:
Exhaust pipe, muffler, heat shields, mounting hardware.
Transmission And Drivetrain:
Gearbox components, clutch assembly, shift mechanism, drive sprocket, chain.
Suspension Front:
Front fork assembly (fork tubes, seals, springs, internal valving components), steering head bearings, triple clamps.
Suspension Rear:
Monoshock absorber, linkage system components, swingarm, rear wheel bearings.
Braking System Front:
Brake caliper, brake disc, master cylinder, brake lever, brake lines.
Braking System Rear:
Brake caliper, brake disc, master cylinder, brake pedal, brake lines.
Wheel And Tire:
Spokes, rims, hubs, wheel bearings, tire sizes, valve stems.
Electrical System:
Wiring harness, lighting components (headlight, taillight, turn signals if applicable), battery, fuses, switches.
Controls And Cables:
Throttle cables, clutch cables, brake cables, control levers, footpegs, handlebars.
Bodywork And Frame:
Frame components, plastic body panels (fenders, shrouds), seat, fuel tank cover.
Disassembly Guidance:
Provides diagrams that facilitate the disassembly of various vehicle sub-assemblies.
Assembly Guidance:
Visual references for reassembling components after repair or replacement.
Part Identification:
Clear identification of all OEM parts with corresponding part numbers.
Part Ordering Reference:
Enables users to confidently order correct replacement parts by providing part numbers.
Depth:
Detailed component-level breakdown, suitable for parts identification and ordering for repair and maintenance.
Usage Scenarios:
Ideal for DIY mechanics, technicians, and parts departments seeking accurate part identification.
Engine Type:
Liquid-cooled, 2-stroke, reed valve induction
Displacement:
239cc (approximately, specific model may vary slightly)
Bore X Stroke:
63.0 mm x 77.0 mm (typical for this engine) - specific part numbers would detail exact dimensions.
Compression Ratio:
7.7:1 (typical, may vary)
Carburetor:
Keihin PWK39 (typical for WR250 models of this era)
Horsepower:
Approx. 35-40 HP (estimated, performance tuning can vary) - parts manual does not list performance figures.
Torque:
Approx. 25-28 lb-ft (estimated) - parts manual does not list performance figures.
Fuel Type:
Unleaded gasoline (87 octane or higher recommended)
Fuel Mixture:
Requires pre-mix of gasoline and 2-stroke oil (typically 32:1 or 50:1 ratio, consult manual for exact specification).
Engine Oil Type:
Yamaha's recommended 2-stroke engine oil (e.g., Yamalube 2) - specific part number for oil might not be listed, but oil filter part numbers would be.
Transmission Oil Type:
Yamaha's recommended transmission oil or SAE 80 API GL-4 hypoid gear oil. Capacity typically around 0.8-1.0 liters. Specific part numbers for transmission oil are not in a parts manual.
Coolant Type:
Permanent type antifreeze coolant (ethylene glycol based) with distilled water. Capacity approx. 0.5-0.7 liters. Specific coolant part numbers not listed in a parts manual.
Spark Plug Replacement:
Recommended every 20-40 hours of use or annually, depending on riding conditions. Specific part number for spark plug available in manual.
Air Filter Cleaning:
Cleaned frequently, typically every few rides or after dusty conditions. Part number for air filter available.
Chain And Sprockets Maintenance:
Regular lubrication and tension adjustment are critical. Part numbers for chain and sprockets are listed.
Top End Rebuild:
Recommended for 2-stroke engines every 50-100 hours of hard use, depending on riding style. Piston, ring, and cylinder part numbers are detailed.
Clutch Inspection:
Inspect clutch plates for wear at regular intervals, typically every 20-30 hours. Clutch plate part numbers are listed.
Brake Fluid Type:
DOT 3 or DOT 4 hydraulic brake fluid. Specific brake master cylinder and caliper part numbers are in the manual.
Power Valve System:
Potential for carbon buildup affecting performance. Parts for the power valve mechanism (springs, seals, linkages) are detailed.
Cooling System Leaks:
Hoses and radiator seals can degrade over time, leading to leaks. All associated hose and seal part numbers are listed.
Suspension Seals:
Fork and shock seals are wear items and require periodic replacement. Fork seal and dust seal part numbers are provided.
Carburetor Tuning:
Requires proper jetting and adjustment for optimal performance based on altitude and temperature. Carburetor jet and needle part numbers are available.
