Yamaha WR250F(P) 2002 Owner’s Service Manual (P/N 5PH-28199-31)

This Yamaha Owner’s Service Manual (P/N 5PH-28199-31) covers the 2002 WR250F(P), with regional specifications for the USA, Europe, Canada, Australia, New Zealand, and South Africa. It combines operating information and race maintenance with detailed engine, chassis, electrical, and tuning procedures.

Searchable PDF and Wiring Detail

Text search and diagram detail: Searchable text is available across the technical sections. Embedded PDF bookmarks open the cover or contents pages rather than individual repair procedures. Small wire-color codes and connector labels in the wiring diagram are readable when enlarged.

One printable PDF contains 690 pages in English, French, German, and Italian, including 23 opening pages of cover material, introductory information, and contents, plus one back-cover page.

Engine Overhaul, Chassis Service and Electrical Diagnosis

These selected repair and maintenance topics illustrate the manual’s coverage. Further sections include starting and break-in guidance and USA-specific spark arrester cleaning.

• Engine overhaul: Step-by-step procedures for engine removal, crankcase separation, crankshaft inspection, cylinder and piston service, clutch repair, and transmission assembly.

• Valve train: Camshaft removal and installation, timing-chain tensioner checks, valve and guide inspection, and valve-clearance adjustment using pad selection tables.

• Carburetor service: Keihin FCR-MX37 disassembly, float-height inspection, accelerator pump timing adjustment, air cut valve inspection, and regional jetting references.

• Cooling and lubrication: Radiator and cooling-system pressure checks, water pump seal replacement, oil strainer maintenance, and trochoid oil pump inspection.

• Brakes and wheels: Front and rear caliper and master cylinder disassembly, brake bleeding, pad replacement, wheel-bearing service, and brake-disc inspection.

• Suspension and steering: Fork disassembly and oil seal installation, steering-bearing replacement, swingarm linkage service, and rear shock spring and bearing work.

• Electrical troubleshooting: Wiring diagrams and fault-finding charts for the ignition, throttle position sensor, and lighting systems, with resistance and voltage checks.

The repair sections suit experienced mechanics equipped for precision measurement and the specified special tools; Yamaha specifically recommends dealer maintenance for the front fork.

Engine Inspection and Assembly References

Exploded views and sequential job instruction charts identify parts, removal requirements, and assembly notes. Together with factory tolerances and component torque tables, they help you establish the work and equipment required before dismantling an assembly.

Internal engine checks: The engine chapter details piston-to-cylinder clearance, ring inspection, crankshaft runout, balancer alignment, and oil pump rotor clearances. Transmission coverage extends to gear engagement dogs, shift forks, the shift cam, and assembly orientation.

Valve timing and fasteners: Camshaft installation illustrations show the timing marks and tensioner arrangement. Torque references include the M9 cylinder-head fasteners; the manual warns that uneven camshaft-cap tightening can damage the cylinder head, caps, and camshafts.

Special-tool references include the crankcase separator YU-1135-A/90890-01135 and fork seal driver YM-01442/90890-01442.

Carburetor Tuning and CDI Fault Finding

The tuning chapter relates atmospheric conditions and throttle opening to main jet, pilot circuit, needle, and leak jet selection. Symptom-based examples distinguish poor acceleration, rich running, and hesitation, with part-number tables for optional tuning components.

Ignition and TPS: Diagnostic charts connect spark testing, switch continuity, ignition-coil checks, and CDI magneto tests. The throttle position sensor section adds variable-resistance checks, replacement, and output-voltage adjustment, helping distinguish sensor, wiring, and ignition-system faults.

The map-controlled CDI explanation includes a 3-D ignition-timing illustration marked as conceptual rather than an actual calibration map. Cable routing diagrams show how leads, control cables, and hoses are arranged during reassembly.

Fork Service and Rear Shock Coverage

Suspension references distinguish regional spring specifications and fork oil settings. Front and rear suspension charts relate handling symptoms to damping, spring selection, and chassis balance; primary and secondary reduction data support drivetrain setup.

Rear shock limits: Coverage includes removal, spring and bearing replacement, installation, and adjustment. It does not provide an internal rebuild procedure for the gas-filled damper cylinder or reservoir, which the manual warns against disassembling.

The fork assembly instructions also address a specific damage risk: a dropped damper rod can damage the internal valve. Follow the complete OEM procedures and use qualified assistance for brake and pressurized-suspension work.

Examples of Valve, Oil and Carburetor Specifications

Cold valve-clearance specifications distinguish intake valves at 0.10–0.15 mm from exhaust valves at 0.17–0.22 mm, supported by separate pad selection tables.

Oil data specify 1.5 L for a periodic change and 1.6 L with oil filter replacement. The spark-plug inspection section gives a gap of 0.7–0.8 mm.

The carburetor tables distinguish the standard USA main jet, #175, from #172 for Europe and #170 for Canada, Australia, New Zealand, and South Africa.