This manual covers the KTM 400 LC4 Enduro and 660 LC4 Enduro models produced between 1998 and 2005. These motorcycles are renowned for their powerful, liquid-cooled, four-stroke, single-cylinder LC4 engines, offering robust torque suitable for demanding off-road and adventure riding. Key features include high-quality WP suspension components, long-travel suspension systems, and a durable chassis designed for challenging terrain. KTM's heritage in off-road racing underpins the engineering of these versatile machines, which were positioned as competitive options in the large-displacement dual-sport and enduro market.

This comprehensive workshop service and repair manual provides detailed guidance for maintenance, troubleshooting, and diagnostics. It covers all essential systems, including the engine, transmission, clutch, chassis, suspension, brakes, and electrical system. The manual includes procedures for routine maintenance, engine overhauls, component rebuilds, and detailed troubleshooting guides with diagnostic flowcharts. With specific torque values, clearances, and high-resolution wiring diagrams, this manual is an indispensable resource for owners and technicians aiming to maintain and repair these performance-oriented KTM motorcycles.