This manual covers the TTR250, a versatile dual-sport motorcycle produced from 1999 to 2006. Known for its robust engineering and user-friendly design, the TTR250 is a capable machine for both trail riding and general use, inheriting a strong reputation for reliability and performance. This first-generation model, identifiable by VIN code prefixes 54S and 5LU, offers a balance of off-road prowess and street legality, making it a popular choice for enthusiasts seeking adventure. This comprehensive workshop repair service manual provides detailed information for all models, engines, trims, and transmission types within the specified production years. It covers a wide array of systems, including the fuel, cooling, engine lubrication, drivetrain, clutch, and chassis systems, as well as electrical components and wiring diagrams. The manual includes step-by-step repair procedures, diagnostic information, troubleshooting guides, and critical specifications, all presented with hundreds of diagrams and illustrations to assist DIY enthusiasts and professional technicians in maintaining and repairing the TTR250.