This workshop repair service manual covers the Yamaha DT125R for the 1987 and 1988 model years. Known for its off-road heritage and durability, the DT125R is a versatile dual-sport motorcycle powered by an air-cooled, single-cylinder, 2-stroke engine of approximately 124cc. This manual provides comprehensive factory-level information, ensuring owners and technicians have access to the same detailed guidance used by professional repair shops. The DT125R is designed for a wide range of uses, from trail riding to general transportation, and the reputation for performance and reliability underpins the engineering quality of this model. This comprehensive English-language manual details all aspects of the Yamaha DT125R's maintenance, troubleshooting, and repair. It includes in-depth coverage of the engine, fuel system, clutch, transmission, brakes, suspension, steering, frame, and the complete electrical system, supported by hundreds of diagrams and step-by-step instructions. The manual is designed for professional technician-level understanding, offering solutions for common issues and detailed procedures for assembly, disassembly, and rebuilding. By utilizing this resource, owners and mechanics can efficiently maintain and repair the DT125R, ensuring its optimal performance and longevity.