This manual covers the 65SX, a highly regarded mini motocross bike designed for young riders entering competitive racing. Produced from 1998 through 2003, this model embodies renowned engineering for off-road performance and durability. Its 65cc, liquid-cooled, 2-stroke single-cylinder engine, coupled with a manual clutch and sequential gearbox, provides the power and agility essential for motocross tracks. The 65SX is celebrated for its competitive edge in amateur and junior racing circuits, offering a robust platform for skill development and enjoyment. This comprehensive factory service repair manual provides detailed information for the maintenance and repair of the 65SX engine for model years 1998-2003. It offers step-by-step instructions for disassembling, servicing, and assembling engine components, along with coverage of the electrical and fuel systems. The manual includes periodic maintenance schedules, troubleshooting guides, wiring diagrams, and hundreds of photos and illustrations to assist both do-it-yourself enthusiasts and experienced mechanics. This resource is designed to help owners keep their vehicles in optimal working condition and reduce reliance on costly professional services.