2000–2007 Yamaha TT-R90, TT-R90N & TT-R90NC Owner's Service Manual (P/N 5HN-28199-81)

This Yamaha owner's service manual covers the 2000–2007 TT-R90(N) family, including TT-R90N, California TT-R90NC, and European TT-R90 versions. P/N 5HN-28199-81, first edition May 2000, combines operating instructions with maintenance, repair, and electrical diagnosis.

• Engine repair: Cylinder-head removal, camshaft and rocker-arm service, valve and valve-spring inspection, cylinder and piston measurements, and timing-chain installation.

• Clutch and transmission: Wet clutch and centrifugal primary clutch service, kick axle disassembly, shift shaft removal, and shift fork, shift cam, and transmission assembly.

• Lubrication and crankshaft: Oil-pump disassembly and clearance inspection, rotary-filter and strainer checks, crankcase separation, and crankshaft inspection.

• Fuel and routine maintenance: Carburetor disassembly, float-height and fuel-level adjustment, valve-clearance checks, air-filter cleaning, and maintenance interval charts.

• Brakes and chassis: Front-fork seal replacement, wheel-bearing removal, drum-brake service, steering-head adjustment, swingarm removal, and rear-shock spring-preload adjustment.

• Electrical diagnosis: CDI magneto removal, ignition and carburetor-heating troubleshooting charts, wiring diagrams, coil tests, thermo-switch checks, and heater-resistance testing.

The repair sections suit mechanics and experienced owners with engine-service skills, precision measuring tools, and the electrical test equipment specified in the manual.

Engine Internals, Clutch, and Transmission

Exploded views and job instruction charts identify the parts involved and the extent of removal for each job. Piston and cylinder measurement drawings accompany the wear checks, while the valve section covers stem-to-guide clearance, seat inspection, and lapping.

Clutch coverage distinguishes the friction plates, steel plates, springs, and centrifugal primary clutch. Crankcase service includes joint-sealing notes and connecting-rod clearance checks; transmission illustrations identify the left and right shift forks and their installed orientation.

The tool references include valve spring compressor YM-4019 / 90890-04019 and flywheel puller YU-33270-B / 90890-01362. Engine data also include compression specifications, cylinder-head fastening requirements, and general torque charts.

The camshaft-installation notes warn that crankshaft movement during assembly can upset valve timing and cause damage. Excessive force when seating valve cotters can also damage a valve.

Carburetor Setup and Routine Service

The Mikuni VM16SH carburetor carries identification mark 5HN1 01. Its service section separates jet and needle inspection from float-height measurement and fuel-level adjustment, including the effect of needle-valve loading on the float-height reading.

Routine service covers throttle-cable and idle-speed adjustment, engine-oil replacement, spark-plug inspection, and USA spark-arrester cleaning. The maintenance charts distinguish scheduled work from pre-ride checks and account for changes in riding conditions.

Engine exhaust requires adequate ventilation; gasoline and its vapors must be kept away from ignition sources.

Forks, Steering, and Drum Brakes

Front-fork disassembly drawings identify the damper rod and oil seal, with special-tool references and refill data. Steering instructions distinguish the initial bearing-seating torque from the final ring-nut setting.

Wheel and brake sections cover bearing removal, wheel runout, brake-lining inspection, and shoe replacement criteria. Rear-shock coverage includes removal, inspection, and spring-preload adjustment; the manual specifies replacement of a damaged or leaking shock assembly.

Ignition and Carburetor-Heating Diagnosis

The ignition flowchart helps separate spark-plug, stop-switch, connection, and coil faults before it reaches CDI-unit replacement. A separate carburetor-heating chart covers the thermo switch, heater, source coil, and rectifier/regulator.

The electrical-components wiring diagram includes wire-color codes and connector layouts. Cable-routing diagrams and sectional views show harness and hose placement, while the thermo-switch chart distinguishes its heating and cooling behavior.

Examples of Piston Fit and Carburetor Test Data

These examples are a small selection of the inspection and adjustment specifications included in the manual.

Piston-to-cylinder clearance is specified at 0.025–0.045 mm, with a 0.15 mm service limit. For the Mikuni VM16SH, float height is 15.5–16.5 mm with the float arm resting on, but not compressing, the needle valve.

The carburetor heater test specifies 6–10 Ω at 20°C (68°F), with the measurement points illustrated alongside the test data.

PDF Search, Diagram Detail, and Page Count

Text search and navigation: The PDF contains searchable text. Embedded bookmarks lead to the contents pages rather than directly to individual repair sections. Small wiring-diagram labels require zooming for comfortable reading.

Supplied as one printable 288-page PDF containing English, French, and German text. The total includes two cover pages, five memo pages, three maintenance-record pages, and one blank page.