2000–2001 Yamaha TT-R125(M)Service & Repair Manual (P/N 5HP-28199-80)

• Model-specific coverage: Identifies the TT-R125M for the U.S. outside California, Canada, Australia, and New Zealand; TT-R125MC for California; and TT-R125 for Europe. Model code 5HP1 applies to the U.S. outside California, 5HP2 to California, Australia, New Zealand, and Europe, and 5HP3 to Canada.
• Engine and carburetor procedures: Covers carburetor removal and disassembly, fuel-level and pilot-air adjustment, cylinder-head service, camshaft and rocker-arm inspection, valve and valve-guide work, and cylinder, piston, and ring repair.
• Bottom-end and transmission repair: Details engine removal, clutch and primary-drive service, oil-pump overhaul, kick and shift shaft work, CDI magneto removal, crankcase separation, crankshaft and balancer inspection, and transmission, shift-cam, and shift-fork service.
• Chassis workshop coverage: Includes front and rear wheel removal, drum-brake and wheel-bearing service, front-fork disassembly and seal replacement, steering-head work, swingarm and linkage inspection, and rear-shock removal and installation.
• Inspection and adjustment content: Provides maintenance schedules, pre-operation checks, oil-pressure inspection, valve-clearance and idle adjustment, brake and drive-chain setup, spoke and wheel inspection, steering-head adjustment, suspension checks, and lubrication points.
• Ignition diagnosis and visual references: Supplies three cable-routing drawings, a color-coded CDI wiring schematic, an ignition no-spark flowchart, electrical test specifications, component-specific torque data, wear limits, clearances, and exploded job views.

What This Yamaha Publication Covers

This 442-page PDF contains Yamaha's trilingual TT-R125(M) Owner's Service Manual in English, French, and German. It is the 1st Edition, November 1999, identified by Yamaha manual number 5HP-28199-80. Six chapters move from general information and specifications through regular inspection and adjustment, engine repair, chassis repair, and the electrical system.

The material is suited to experienced owners performing routine service and mechanics taking on component-level repair. Yamaha marks selected maintenance work as requiring special tools, service data, and technical skill, and recommends dealer attention for the front fork because of its sensitive internal construction.

Engine and Drivetrain Detail

The carburetor section breaks the Mikuni unit down to the float, needle valve, jets, pilot-air screw, throttle valve, and starter plunger, then covers inspection, assembly, installation, and fuel-level checking. Top-end repair reaches well beyond adjustment work: camshaft and rocker-arm checks, valve-guide replacement and reaming, valve-seat contact inspection and lapping, spring inspection, and piston, ring, cylinder, and timing-system service are all documented.

For deeper engine work, the manual follows the clutch plates and primary drive through the oil pump, kick mechanism, shift shaft, rotor and stator, engine removal, crankcase separation, crankshaft, balancer, and five-speed transmission. The illustrated job charts identify removal scope, part sequence, required new seals or circlips, specified lubricants and locking agents, inspection limits, and assembly torque references.

This is the standard-wheel, kick-start configuration. The specifications identify a 70/100-17 front tire and 90/100-14 rear tire, so buyers looking for TT-R125LW large-wheel or electric-start coverage need a different model-specific publication.

Chassis and Ignition Scope

Wheel and drum-brake sections combine removal and reassembly with rim, spoke, bearing, axle, brake-lining, and drum inspection. The front-fork chapter covers oil-seal and damper-rod removal, internal inspection, oil filling, reassembly, and installation. Steering and swingarm sections add bearing, race, bushing, connecting-arm, and relay-arm service.

Rear-shock coverage has a clear boundary: the gas-charged unit is covered for removal, bushing service, external inspection, spring-preload adjustment, and installation, but Yamaha warns against opening it. Gas-pressure release for disposal is identified as a Yamaha-dealer-only operation.

Electrical coverage is focused on the ignition system rather than a battery, lighting, or charging network. The component-location view and wiring diagram identify the CDI unit, engine-stop switch, ignition coil, CDI magneto, and spark plug. The no-spark inspection chart then isolates connections, the stop switch, primary and secondary coil windings, pickup and charging coils, and the CDI unit using the listed spark and resistance tests.

Tools, Diagrams, and Repair Cautions

The special-tool list gives paired North American and other-market numbers. Examples include the crankcase separating tool YU-01135-A / 90890-01135, valve spring compressor YM-04019 / 90890-04019, fork-seal driver weight YM-33963 / 90890-01367 and attachment YM-33281 / 90890-01400, and ignition checker YM-34487 / 90890-06754. Exploded views for the carburetor, crankcase/crankshaft/balancer, and front fork show assembly relationships without separating the illustrations from the associated job tables.

The manual calls out model-specific repair traps. Turning the crankshaft during camshaft installation can cause damage or incorrect valve timing, while allowing the fork damper rod to drop into a vertically held inner tube can damage the rod. Fork and gas-charged shock work also involves stored-energy hazards; follow Yamaha's handling warnings and use qualified service support where the publication calls for dealer-level tools or skills.