This manual covers the KTM 400 SX engine, produced for the model years 1998 through 2005. The 400 SX is a high-performance off-road motorcycle renowned for its powerful single-cylinder engine, a hallmark of KTM's dedication to competitive motocross and enduro disciplines. These engines are engineered for robust performance, offering a balance of power and control crucial for demanding riding conditions. The model's lineage is rooted in KTM's extensive experience in off-road racing, where reliability and potent power delivery are paramount.

This comprehensive Service and Repair Manual provides detailed technical information and procedural guidance for the KTM 400 SX engine. It encompasses engine assembly, disassembly, inspection, overhaul, performance tuning, lubrication, cooling, and ignition systems. The manual also covers drivetrain components, electrical systems related to the engine, and essential maintenance procedures such as fluid changes and valve adjustments. Troubleshooting guides, diagnostic charts, and technical specifications, including torque values and tolerances, are included to assist owners, mechanics, and technicians in maintaining and repairing the vehicle effectively.