2000–2001 Yamaha WR400F, WR400FM & WR400F(M) Owner's Service Manual

This Yamaha Owner's Service Manual covers the 2000–2001 WR400F, WR400FM, and WR400F(M) in the WR Series, with regional specifications for the USA, Europe, Canada, Australia, New Zealand, and South Africa.

• Engine and transmission repair: Engine removal, crankcase separation, crankshaft inspection, valve and piston service, clutch disassembly, and transmission gear and shift-fork inspection.

• Carburetor service: Keihin FCR-MX39 disassembly, jet and float inspection, accelerator-pump and air-cut-valve service, and cold- and hot-start plunger checks.

• Cooling and lubrication: Cooling-system pressure tests, radiator inspection, water-pump seal replacement, trochoid oil-pump inspection, and lubrication diagrams.

• Brakes and steering: Front and rear caliper and master-cylinder service, brake-system air bleeding, wheel-bearing replacement, and steering-head inspection and adjustment.

• Suspension service: Telescopic fork disassembly and oil-seal replacement, swingarm and linkage bearing service, and Monocross rear-shock spring and damping adjustments.

• Electrical troubleshooting: Ignition, throttle position sensor (TPS), and lighting-system diagnostic charts, wiring diagrams, connector illustrations, and component test specifications.

The manual combines information for owners learning operation and basic maintenance with repair procedures written for mechanics; internal repairs require the special tools and measuring equipment identified in the relevant sections.

Engine, Valvetrain, and Transmission

Setup, break-in procedures, and regular inspection schedules lead into engine oil and coolant service. The engine chapters extend through cylinder-head, valve-guide, piston, and crankshaft work, with exploded views and job charts accompanying disassembly sections.

Valve-clearance adjustment includes the Pad Selection Table. Camshaft inspection covers lobe dimensions and bearing clearance, while the transmission section addresses gear dogs, shift forks, and assembly checks. The balancer shaft, kick axle, and shift shaft have their own removal, inspection, and installation procedures.

The special-tool references include the crankcase separating tool, YU-01135-A / 90890-01135. Component-specific torque tables and wear limits support the individual repair sections.

Carburetor, Cooling, and Oil Circulation

Carburetor coverage includes float-height measurement and accelerator-pump diaphragm inspection. Regional jet-needle specifications and symptom-based tuning examples distinguish baseline settings from adjustments for operating conditions.

The starting section explains the risks of spark-plug fouling and kickback when the throttle is operated during kickstarting. It also warns that using the manual decompression lever while the engine is running can damage the engine.

Water-pump service covers the impeller shaft, bearing, and seals. The trochoid oil-pump section includes rotor-clearance inspection, supported by the Lubrication Chart and Lubrication Diagrams showing oil circulation through the engine and transmission. Cooling-system coverage includes pressure testing and capacity specifications.

Brakes, Forks, and Rear Suspension

Brake service goes beyond pad replacement to caliper pistons, seals, and master-cylinder components. Steering and swingarm sections cover bearing inspection and replacement.

Fork procedures include damper-rod removal and oil-seal installation with the specified fork seal driver, YM-01442 / 90890-01442. Yamaha recommends dealer maintenance for the front fork.

Rear-shock coverage includes removal, spring and bearing service, and preload and damping adjustment. The nitrogen-charged cylinder and reservoir are subject to an explicit warning against disassembly, so this section should not be read as an internal shock-rebuild guide.

Follow the manual's torque specifications and safety precautions for engine work and suspension disassembly.

Ignition, TPS, and Lighting Diagnosis

The ignition troubleshooting chart checks switches, coils, the magneto, and wiring before CDI replacement, helping narrow down a no-spark fault. TPS coverage includes resistance checks, replacement adjustment, and input-voltage testing; the lighting section addresses the switch, lighting coil, connections, and regulator.

The Wiring Diagram and Cable Routing Diagram support electrical tracing and harness installation. The 3-D Image Map of Ignition Timing explains how the map-controlled CDI uses engine speed and throttle position; it is a conceptual illustration, not the actual ignition calibration.

Engine and Chassis Tuning

The tuning chapter relates carburetor settings to atmospheric conditions and throttle opening. Chassis coverage includes sprocket selection, spring options, and suspension symptom charts linking handling complaints to checks and adjustments, with regional baseline settings identified separately.

Valve, Fork, and Ignition Data Preview

Cold valve-clearance specifications are 0.15–0.20 mm for the intake and 0.25–0.30 mm for the exhaust.

Standard fork oil level is 125 mm for Europe and 135 mm for the other covered markets. Measurement is from the outer-tube top, with the inner tube and damper rod fully compressed, the spring removed, and the spring guide installed.

The ignition tests specify pickup-coil resistance of 248–372 Ω at 20°C (68°F), alongside connector illustrations identifying the test leads.

Searchable Text, Bookmarks, and PDF Contents

Search and diagram detail: The manual body has searchable text, with PDF bookmarks for all seven chapters, the index, contents, and wiring diagram. Cover text is not searchable. Small wiring and connector labels are readable when enlarged.

One printable English-language PDF contains 292 pages, including one cover page and 11 introductory, index, and contents pages.