This manual covers the KX125 and KX250 models produced between 2003 and 2008. These highly regarded motocross bikes are known for their powerful two-stroke engines, advanced suspension, and competitive chassis, making them a favorite for racing and aggressive trail riding. The long-standing legacy in motocross is evident in the performance and engineering of these machines, which were designed to excel in demanding off-road conditions. Throughout their production years, these models received updates aimed at enhancing their already formidable capabilities. This comprehensive Service Repair Manual provides detailed information essential for the maintenance, repair, and troubleshooting of your KX125 or KX250. It covers a wide array of systems, including engine components such as the fuel system, cooling system, and internal engine parts, as well as chassis elements like the brakes, suspension, and frame. Additionally, it delves into the electrical system and offers in-depth procedures for assembly, disassembly, and diagnostics. This resource is invaluable for owners, mechanics, and technicians seeking to maintain the peak performance and reliability of their motorcycles.