The TRI-Z 250, identified by model designations YTZ250 and YTZ250N, represents a pioneering high-performance sport All-Terrain Vehicle (ATV) from the mid-1980s. As a key player in the evolution of sport ATVs, the TRI-Z 250 is celebrated for its potent 236cc two-stroke liquid-cooled engine, a 6-speed manual transmission with a wet multi-plate clutch, and robust hydraulic disc brakes. Its engineering quality is evident in its durable steel frame and its reputation as a dominant machine in its class, directly competing with other performance ATVs of its era. This model offers an exciting and capable riding experience, making it a sought-after machine for enthusiasts and collectors alike. This comprehensive workshop service repair manual in English provides detailed, factory-authorized information for all TRI-Z 250 models. It covers essential areas including engine mechanics, drivetrain, chassis and suspension, and the electrical system, offering step-by-step procedures for maintenance, repair, and overhaul. The manual is designed for professional technicians and DIY mechanics, featuring detailed diagrams, critical specifications, and troubleshooting guidance to ensure optimal performance and longevity of the vehicle. With its professional-level depth and instructional clarity, this manual is an indispensable resource for anyone looking to maintain, diagnose, or repair their TRI-Z 250.