The YZ400F, a four-stroke motocross model, represents a significant advancement in off-road performance, marking a strategic transition into the four-stroke engine platform. Production years are indicated by model codes K, L, and C. This high-performance machine is engineered for competitive motocross racing, emphasizing potent power delivery, agile handling, and robust suspension. Its design prioritizes rider control and the inherent advantages of a four-stroke engine, including improved torque and a broader powerband compared to contemporary two-stroke counterparts. With its liquid-cooled, 399cc engine featuring a five-valve DOHC configuration and a Keihin FCR flat-slide carburetor, the YZ400F delivers exhilarating performance on the track.

This comprehensive service repair manual provides in-depth guidance for the maintenance and repair of your YZ400F. It covers all essential systems, including the engine's top and bottom ends, lubrication, cooling, fuel, transmission, chassis, brakes, and electrical components. Detailed procedures for routine maintenance, troubleshooting common issues, complete disassembly and reassembly, and technical specifications are included. This manual is an indispensable resource for owners and technicians, ensuring the YZ400F remains in optimal condition for peak performance and longevity through expert-level technical information and clear instructions.