Yamaha TT-R125(P) / TT-R125LW(P) 2002 Owner's Service Manual (P/N 5HP-28199-83)

This Yamaha Owner's Service Manual, P/N 5HP-28199-83, covers the 2002 TT-R125(P) and TT-R125LW(P). It combines operating instructions and scheduled maintenance with engine, chassis, and ignition-system repair procedures.

PDF Search, Bookmarks, and Diagram Detail

Text search and navigation: Body text is searchable; lettering within the wiring-diagram image is not. Embedded bookmarks mainly open the language-specific contents pages, rather than individual repair sections. Small wiring labels are readable with zoom.

One printable 506-page PDF contains English, French, and German text. The total includes 25 cover and introductory pages, three memo pages, and the final publisher-imprint page.

Engine Overhaul, Chassis Service, and Ignition Testing

The following selected topics outline the service coverage. Other sections address starting and break-in, along with cleaning and storage.

• Routine maintenance: Pre-ride checklists, maintenance intervals, drive-chain inspection and adjustment, cable lubrication, torque-check point maps, and component-specific tightening tables.

• Engine repair: Engine removal, cylinder-head and piston inspection, valve and valve-guide service, camshaft work, crankcase separation, and crankshaft and balancer installation.

• Clutch and transmission: Step-by-step clutch-plate replacement, primary driven gear service, and gearbox disassembly and assembly, including the shift cam and shift forks.

• Carburetor and lubrication: Mikuni VM20SS carburetor disassembly, needle-valve and fuel-level checks, pilot-air and idle adjustment, plus oil-pump inspection.

• Brakes and suspension: Model-specific front-brake service, rear drum-brake repair, front-fork overhaul, steering-bearing work, swingarm and linkage inspection, and rear-spring preload adjustment.

• Ignition diagnosis: Wiring diagram, ignition inspection flowchart, spark-gap testing, engine-stop-switch checks, and ignition-coil and CDI-magneto resistance tests.

The operating sections address owners, while the internal repair chapters suit mechanics with measuring equipment and special tools; Yamaha directs dealer-marked maintenance to a dealer.

Internal Engine Inspection and Reassembly

The repair chapters extend to valve-seat refacing and lapping, piston-ring checks, and crankshaft measurements. A piston/cylinder matching chart pairs lettered cylinder groups with color-coded piston sizes, helping identify compatible replacement parts.

Assembly references: Oil-pump and shift-cam exploded views accompany component inspection and assembly notes. Transmission details identify shift-fork positions and the different guide-bar lengths, with checks for smooth shifting after assembly.

The special-tool tables identify the crankcase separator as YU-1135-A/90890-01135 and distinguish U.S./Canadian tool numbers from other-market numbers. Valve-service cautions explain how excessive impact at the valve tip can damage the valve.

Carburetor Inspection and Individual Settings

Carburetor coverage includes the coasting enricher, jet needle, float, and needle-valve seat, with illustrated assembly instructions. The pilot-air-screw setting is specific to the individual carburetor; the turn range printed in the manual is an example, not a universal adjustment setting.

Front-Brake Differences and Suspension Scope

Brake configurations: TT-R125 front-brake instructions concern a cable-operated drum. TT-R125LW coverage includes the hydraulic front disc brake, caliper and master-cylinder overhaul, and bleeding. Both models have rear drum-brake service instructions.

Fork repair: The front-fork chapter covers seal replacement, damper-rod inspection, and model-specific oil settings. Its assembly cautions explain how a damper rod can be damaged if it drops into the inner tube.

Rear-shock limits: Coverage includes removal, bushing replacement, inspection, and spring-preload adjustment. A leaking or damaged nitrogen-charged damper is replaced as an assembly; internal damper rebuilding is outside the service procedures.

Tracing a No-Spark Fault

The ignition inspection flowchart connects wiring and stop-switch checks with coil tests before CDI-unit replacement is considered. Test-lead illustrations and wire-color codes relate the resistance specifications to the correct connections.

A well-ventilated workspace and appropriate protective gear remain essential during service.

A Preview of Valve, Head, and Carburetor Specifications

For both covered models, the valve-clearance tables specify cold ranges of 0.08–0.12 mm intake and 0.10–0.14 mm exhaust. Cylinder-head inspection uses a maximum warpage limit of 0.03 mm, alongside the illustrated checking and resurfacing procedure.

The carburetor chapter specifies a fuel level of 6.0–7.0 mm below the float-chamber mating surface, measured with the carburetor and fuel-level gauge held vertically.