Yamaha WR250FX 2008–2012 Owner's Service Manual (P/N LIT-11626-21-56)

This Yamaha OEM Owner’s Service Manual covers the 2008 WR250FX (model code 5UMH). It is the first edition, dated July 2007, P/N LIT-11626-21-56.

Search, Bookmarks, and Wiring Detail

Finding service information: The service text is searchable, and embedded bookmarks open chapters and individual procedures. The warning page, warranty body, and labels inside the wiring diagram are graphical. Zoom in to read the small wire and connector codes.

The ZIP download contains one printable PDF with 314 pages, including the front and back covers, 12 pages of front matter, and one blank page.

Competition Maintenance, Engine Repair, and Electrical Diagnosis

The highlights below are a selection from the manual. Yamaha also covers break-in and spark arrester cleaning for U.S. models.

• Maintenance: Separate charts cover emissions service, general maintenance and lubrication, and competition intervals, with pre-ride checks and service notes for varying riding conditions.

• Engine and drivetrain: Step-by-step procedures cover engine removal, camshaft timing, crankshaft replacement, and transmission disassembly, including wet-clutch, shift-cam, and shift-fork inspection.

• Carburetor and emissions: KEIHIN FCR-MX37 service covers internal inspection, float-height adjustment, and accelerator-pump timing. The air-induction system has its own test procedure.

• Fork and brakes: Front-fork overhaul covers internal inspection and seal replacement. Hydraulic brake procedures cover caliper and master-cylinder disassembly and system bleeding.

• Electrical diagnosis: CDI ignition and electric-start flowcharts cover no-spark and no-crank faults. The electrical chapter also covers charging-system checks and throttle position sensor testing and adjustment.

The maintenance chapters give owners pre-ride and routine service procedures. Yamaha’s engine, chassis, and electrical repair sections assume basic Yamaha motorcycle service skills.

Engine, Cooling, and Drivetrain Repair

Cylinder head: Coverage includes valve-guide replacement, valve-seat inspection and lapping, and separate intake and exhaust charts for choosing valve-adjustment pads. Camshaft inspection includes Plastigauge journal-clearance measurement and checks of the automatic decompression mechanism. Yamaha warns that uneven camshaft-cap bolt removal or tightening can damage the cylinder head, camshafts, or caps.

Bottom end and cooling: The engine chapter covers balancer-gear alignment, oil-pump rotor inspection, and starter-clutch operation on the kick- and electric-start engine. Lubrication diagrams trace oil through the dry-sump system. Cooling procedures cover water-pump seal and bearing replacement, radiator-cap testing, and system pressure checks for leaks.

Carburetor and Air-Induction Service

Carburetor inspection extends to the cold- and hot-starter plungers and the air-cut valve diaphragm. The separate air-induction section uses airflow and vacuum checks to test the emissions-system air cut-off valve.

Chassis Tuning and Suspension Scope

The chassis chapter covers steering-head bearing replacement and preload adjustment, plus swingarm and linkage bearing service. The front-fork and rear-shock suspension setting charts link handling symptoms to setup changes. The tuning chapter also covers sprocket selection, spring choice, rider sag, fork oil level, and damping.

Rear-shock procedures cover removal, installation, external adjustment, and spring and mounting-bearing service. Yamaha specifies complete shock replacement for oil or gas leaks. During front-fork assembly, dropping the damper rod into the inner tube can damage the valve inside.

Electrical Diagnosis and Cable Routing

The wiring diagram comes with a wire-color key and a component legend. For a no-crank fault, the diagnostic checks help separate a starter-motor problem from a neutral switch, clutch switch, relay, or diode fault. Starter-motor inspection covers the brushes, commutator, armature, and insulation.

The manual also covers speed-sensor and multifunction-display diagnosis, BASIC and RACE modes, and tripmeter correction. Cable routing diagrams show the paths for wiring, control cables, carburetor hoses, and brake hoses.

Factory Tools and Service Tables

Tool references include the YU-1135-A crankcase separating tool, YM-01494 damper rod holder, and YM-A0948 fork seal driver. The tool table pairs U.S. and Canadian references with alternate 90890-series numbers. Factory tables give component-specific tightening torques, camshaft clearances, clutch wear limits, fluid capacities, and electrical test values.

Use proper shop procedures and protective gear. Have a qualified technician verify critical brake and suspension repairs before riding.

Selected Piston, Carburetor, and Ignition Specs

The standard piston-to-cylinder clearance is 0.030–0.055 mm.

The carburetor’s specified float height is 8 mm, measured with the float arm just resting on the needle valve.

For ignition diagnosis, the AC magneto pickup coil is specified at 248–372 Ω at 20 °C (68 °F).