This manual covers the WR450F and WR450FR dual-sport and off-road motorcycles produced between 1998 and 2007. There is a renowned heritage in performance motorcycle engineering, and the WR450F series embodies this with its powerful liquid-cooled, 4-stroke engine, robust chassis, and capable suspension designed for demanding off-road conditions. Known for its reliability and adaptability for trail riding and enduro competition, this generation represents a key period in the model's development, building upon extensive experience in motocross technology. This comprehensive factory service repair manual provides detailed, step-by-step instructions, drawings, and diagrams necessary for all maintenance, repairs, and diagnostics. It covers essential systems including the fuel system, cooling system, engine top end, clutch, lubrication system, transmission, brakes, suspension, steering, frame, and electrical system. The manual is designed to empower owners and technicians by offering factory-level technical information, enabling them to effectively maintain, troubleshoot, and repair their WR450F/WR450FR, ultimately ensuring optimal performance and longevity.