This manual covers the 1999 KTM 400 LC4 and 660 LC4 models, dual-sport motorcycles renowned for their robust LC4 single-cylinder engine, high-quality WP suspension, and strong chromoly steel frame. Embodying KTM's 'Ready to Race' philosophy, these bikes are engineered for off-road performance with street-legal capabilities, making them suitable for trail riding, adventure touring, and daily commuting. The LC4 platform, a cornerstone of KTM's lineup since the late 1980s, is celebrated for its torque, durability, and competitive edge in segments like the Dakar Rally.

This comprehensive workshop repair service manual provides detailed procedures for all repairs, from routine maintenance to complete component rebuilds. It covers essential systems including the engine, fuel, ignition, cooling, transmission, suspension, brakes, electrical, and bodywork. The manual includes diagnostic troubleshooting, technical specifications, torque values, and information on special tools required for servicing the 1999 KTM 400 and 660 LC4 models. Its purpose is to assist dealership technicians and owners in maintaining and repairing these vehicles, ensuring optimal performance and longevity.