This Workshop Service Repair Manual covers the KTM 125 SX, 250 SX, 125 EXC, and 250 EXC models produced between 1999 and 2008. These high-performance off-road motorcycles are renowned for their racing prowess, with a heritage rooted in Motocross and Enduro championships. Engineered in Austria, these models feature robust chromium-molybdenum steel frames, powerful two-stroke engines, and advanced suspension systems, making them highly competitive in their segment. The SX and EXC lines represent a significant era of KTM's two-stroke development, consistently praised for their performance and durability.

This comprehensive manual provides in-depth technical guidance for the engine systems of these KTM motorcycles. It details complete engine rebuild procedures, component inspection and measurement, torque specifications, and replacement of critical parts such as pistons, rings, bearings, and seals. The manual also covers carburetor cleaning and adjustment, ignition system aspects, and clutch and gearbox service related to the engine interface. With an estimated 500+ pages of information in English, this manual is an essential resource for owners, mechanics, and technicians to maintain, diagnose, and repair the core mechanical heart of these competition off-road machines, ensuring optimal performance and longevity.