This document provides comprehensive engine repair and maintenance information for 125 and 200 models manufactured between 1998 and 2002. Known for its strong off-road racing heritage, these lightweight performance motorcycles were designed to offer agility and power within their displacement class. This manual, presented in English, serves as a professional-grade resource, consolidating information from various supplements to cover specific model year updates and incremental changes made during this period. It is an invaluable tool for owners, independent repair shops, and enthusiasts seeking to maintain and repair these performance-oriented machines. The scope of this manual is focused on detailed engine repair, covering everything from removal and disassembly to the servicing of individual components and reassembly. It includes in-depth guidance on engine mechanicals, lubrication, and fuel system specifics, along with troubleshooting common engine problems. Technicians and owners will find comprehensive technical specifications, diagrams, torque values, and step-by-step instructions for procedures such as cylinder honing, piston and ring replacement, and clutch servicing. The manual also details periodic maintenance schedules, fluid specifications, and diagnostic procedures, empowering users to perform thorough maintenance, diagnosis, and repair, akin to dealership-level service.