The KTM 400 LC4 Enduro and 660 LC4 Enduro models from 2003 represent a pinnacle of Austrian engineering, renowned for their potent single-cylinder performance and robust construction. These high-performance dual-sport motorcycles are built for enthusiasts who demand capability both on and off the road. The LC4 designation signifies a liquid-cooled, four-stroke, single-cylinder engine, a design celebrated for its torque and reliability in demanding conditions. With a heritage rooted in off-road racing, KTM's LC4 platform has consistently delivered a compelling blend of power and durability, making these models a distinguished choice for adventure and enduro riding.

This comprehensive service repair manual is meticulously designed to cover the engine service and repair of the KTM 400 LC4 Enduro and 660 LC4 Enduro. It provides detailed, step-by-step instructions for engine disassembly and reassembly, routine maintenance procedures, and troubleshooting common issues. The manual includes critical technical specifications, torque values, and information on specialized tools required for various tasks. Its scope extends to the cylinder head, valves, pistons, crankshaft, lubrication and cooling systems, fuel and ignition systems, clutch, and transmission, offering essential guidance for owners and technicians to effectively maintain and repair these motorcycles.