This manual covers the 400 SX, 450 SX, 400 MXC, 450 MXC, 400 XC, and 450 XC models manufactured between 2000 and 2007. These high-performance off-road motorcycles, powered by the robust LC4 engine family, are renowned for their potent performance, capable suspension, and aggressive design, making them suitable for motocross, cross-country, and enduro racing. The legacy in off-road competition is reflected in the engineering quality and durability of these machines, which have earned numerous accolades.

This comprehensive factory service and repair workshop manual provides in-depth guidance for owners and technicians. It details essential maintenance procedures, from routine checks and fluid changes to critical component adjustments and rebuilds. The manual covers all major systems, including the engine, transmission, chassis, suspension, brakes, and electrical systems, offering step-by-step instructions, troubleshooting tips, and essential technical specifications. The scope of this manual ensures that users can effectively maintain, diagnose, and repair their motorcycles, maximizing performance and longevity.