This manual covers the KTM 400 LC4 and 660 LC4 models from 2003, built on the robust and versatile LC4 liquid-cooled, 4-stroke single-cylinder engine platform. Renowned for their strong torque and adaptability, these motorcycles have a legacy rooted in KTM's off-road and performance heritage. The LC4 platform is known for its durability and has been a staple for riders seeking a capable machine for various disciplines, from street riding to more adventurous pursuits.

This comprehensive Factory Service Repair Manual in English provides in-depth information for owners and technicians. It details all essential maintenance procedures, including oil changes, filter replacements, and valve clearance checks, along with specific fluid and torque specifications. The manual also offers extensive troubleshooting guidance, step-by-step repair procedures for all major systems such as the engine, transmission, brakes, and suspension, and includes crucial wiring diagrams and information on specialized tools.