YAMAHA WR400F - Advanced, short-stroke, high compression engine, featuring a low friction, ceramic composite plated bore 5-valve head, FCR carburettor with accelerator pump and TPS (throttle position sensor), as well as being short from top-to-bottom and front-to-rear, the new WR400F engine is also very narrow. Only marginally wider than the WR250Z 2-stroke engine. The new 12 litre fuel cell features a 4.5 litre reserve capacity.

Incorporated in the design of the new WR400F  is a five-speed wide ratio gearbox and other off-road 'goodies' such as a CDI magneto with lighting coil, 60 watt halogen headlight and 5 watt tail light. A large enduro-style 1.15 litre radiator with reservoir tank keeps things cool while a steel driven sprocket and sealed chain offer greater longevity. For optimum puncture resistance and wider tyre selection, the WR400F comes with an 18-inch rear rim. The WR400F is ADR compliant with street-legal instrumentation that includes a compact speedometer and trip meter.