2002 Yamaha TT-R125(P) / TT-R125LW(P) Factory Service & Repair Manual • P/N 5HP-28199-83

• Details the 2002 Yamaha TT-R125 and TT-R125LW, including TT-R125P and TT-R125LWP trim variations
• Official Yamaha OEM publication (P/N 5HP-28199-83) spanning 506 pages of technical data in a high-resolution PDF format
• Contains comprehensive exploded-view diagrams, torque-check point maps, and critical baseline data for professional repair work
• Includes complete teardown procedures, CDI magneto diagnostics, transmission rebuilds, suspension tuning, brake system bleeding, and ignition system testing
• Covers crucial assemblies like the cylinder head, shift cam, primary driven gear, front fork, swingarm, and the entire electrical system

Mechanical Overhaul and Maintenance Guidelines

This factory publication provides the technical foundation for servicing the Yamaha TT-R125 platforms. The document outlines exact inspection and adjustment parameters for the engine, chassis, and electrical systems. Mechanics will find complete outlines covering cylinder head and piston maintenance, transmission adjustments, and carburetor tuning, alongside dedicated troubleshooting sections for the electrical network. Visual references such as wiring diagrams, shift cam exploded-views, oil pump schematics, and valve clearance charts eliminate mechanical ambiguity.

Step-by-step instructions detail complex, labor-intensive tasks such as valve clearance adjustments, front fork overhauls, and full clutch plate replacements, empowering you to perform high-level workshop procedures internally. A common pitfall during the TT-R125 overhaul is neglecting the exact alignment of the shift cam and guide bars, which can lead to severe transmission binding. Furthermore, failing to properly seat the primary driven gear thrust plate often results in premature clutch basket wear. Precise cable routing diagrams support various sub-models to ensure accurate component reassembly. Standard workshop safety protocols apply when handling motorized vehicles; a well-ventilated environment and appropriate protective gear remain essential throughout any mechanical intervention. Furthermore, this manual serves purely as a descriptive reference, detailing the complex repair processes necessary to maintain these off-road motorcycles without providing direct tutorials.

Key Technical Specifications

The engine maintenance charts list the engine compression ratio at 10.0:1. Technicians will also find the maximum cylinder head warp limit of 0.03 mm alongside the intake valve cold lash setting of 0.08–0.12 mm directly within the specification tables. For fluid capacities, the document specifies a 6.6 L fuel tank capacity, which includes a 1.9 L reserve allocation. By providing the exact factory-specified valve timing and float height measurements, this document allows technicians to restore optimal throttle response and engine compression without relying on generic aftermarket estimates. All mechanical tolerances and intervals reflect Yamaha's original factory benchmarks.