This Workshop Service Manual provides comprehensive documentation for the 1983-1986 YTM200 (Tri-Moto, Yamahauler), YTM225 (Tri-Moto), and YFM200 (Moto-4) All-Terrain Vehicles. These models represent a significant era in ATV development, offering robust engineering and reliable performance for both recreational and utility purposes. The manual covers a range of engine displacements, from approximately 196cc to 222cc, featuring air-cooled, 4-stroke, SOHC gasoline engines, and manual transmissions with wet multi-plate clutches. Key features include models like the YTM200EK, YTM225DXK, YTM200L, YTM225DXL, YFM200N-S, YTM200N, YTM225DXN, and YFM200DXS, reflecting a pioneering role in the burgeoning ATV market of the mid-1980s. This English-language manual is designed to be an indispensable resource for owners, mechanics, and technicians. It details all major systems, including the engine, clutch, transmission, fuel system, electrical system, suspension, steering, and brakes. The manual covers routine maintenance, lubrication, tune-up procedures, and in-depth repair instructions, from basic adjustments to complete engine and transmission rebuilds. Troubleshooting guidance and diagnostic procedures are thoroughly explained, enabling users to effectively maintain and repair their ATVs, ensuring longevity and optimal performance. The comprehensive scope of this Workshop Service Manual is essential for preserving the operational integrity and value of these vintage off-road vehicles.