This manual covers the 2007 competition motocross motorcycles renowned for their off-road racing heritage and performance. These models feature a four-stroke, single-cylinder, liquid-cooled LC4 engine with displacements of approximately 449.3 cc for the 450 SX-F and 477.3 cc for the 505 SX-F. They are equipped with a 4-speed manual transmission, a wet multi-plate clutch, and a chromium-molybdenum steel central tube frame, embodying a focus on agility and power in the motocross segment. This comprehensive service repair workshop manual provides detailed instructions for maintenance, repair, and troubleshooting of the 450 SX-F and 505 SX-F. It covers all major systems, including engine specifications, transmission, chassis, suspension, electrical systems, bodywork, and intake/exhaust components. The manual offers step-by-step procedures for routine maintenance, engine rebuilds, suspension overhauls, and electrical diagnostics, along with advanced troubleshooting guides and technical specifications, making it an invaluable resource for owners, independent repair shops, and professional dealerships.