This manual covers the 450 SX-F and 450 XC-F models from the 2008 and 2009 model years. These high-performance off-road motorcycles are engineered for competitive motocross and cross-country racing, embodying a 'Ready to Race' philosophy. Known for their powerful 4-stroke, single-cylinder engines, robust suspension systems, and agile handling, these machines are designed to deliver maximum performance in demanding off-road conditions. The 450 SX-F is tailored for motocross tracks, while the 450 XC-F is optimized for cross-country events, both benefiting from extensive racing heritage and development. This workshop service repair manual provides comprehensive A-Z coverage for all aspects of the 450 SX-F and 450 XC-F, including detailed procedures for engine, fuel system, cooling system, transmission, electrical system, chassis, suspension, brakes, wheels, tires, and bodywork. It includes routine maintenance schedules, troubleshooting guides for common issues, step-by-step repair instructions, and complete rebuild procedures. Essential technical specifications, such as torque values, clearances, fluid capacities, and diagnostic information, are also included, making this manual an indispensable resource for owners and technicians seeking to maintain, repair, and optimize their motorcycles.