1986–1989 Honda TRX250R FourTrax ATV Service Manual (P/N 61HB903)

This Honda factory service manual covers the 1986–1989 TRX250R FourTrax ATV, with model-year notes for the carburetor, clutch, transmission, suspension, and electrical system. The manual order number is 61HB903.

• Engine repair: Cylinder-head, cylinder and piston inspection, crankcase separation, crankshaft bearing replacement, and transmission disassembly and reassembly.

• Clutch and starting: Wet-clutch inspection, clutch-lifter service, balancer alignment, gearshift-linkage repair, and kick-starter removal and installation.

• Fuel system: Carburetor rebuilding, reed-valve inspection, air-screw adjustment, and altitude/temperature jetting tables supported by carburetor cutaway views.

• Cooling system: Radiator and cap pressure testing, coolant replacement and bleeding, and water-pump shaft, bearing, and mechanical-seal service.

• Chassis and suspension: Steering-shaft and wheel-bearing replacement, rear-axle service, swingarm/linkage inspection, and Pro-Link shock absorber servicing.

• Hydraulic disc brakes: Twin-piston caliper and master-cylinder repair, pad and disc inspection, brake bleeding, and parking-brake service.

• Electrical diagnosis: Alternator, ignition-coil and pulse-generator tests, AC-regulator checks, switch-continuity charts, and model-year wiring diagrams.

This manual suits mechanics and experienced owners who already understand standard workshop procedures and have the tools needed for component inspection and repair.

Top-End and Crankcase Repair

Cylinder and piston service includes an A/B code-matching chart and oversize-piston guidance. This helps identify compatible cylinder/piston combinations before replacement parts are selected.

Top-end work can be performed with the engine installed; transmission and crankshaft repair require engine removal. The transmission drawings distinguish the 1986 C6 gear from later versions, which are not interchangeable.

Tool references include rotor puller 07733-0010000 and clutch center holder 07724-0050001. The cylinder-installation cautions explain how rotating the cylinder can snag and break the piston rings.

Carburetor Setup and Cooling Repairs

Carburetor data separates PJ05A, PJ07A, PJ07B, and PJ07C versions. Carburetor-operation diagrams explain the overlap between metering circuits, while the Altitude and Temperature Adjustment chart supplies jetting and jet-needle settings.

The carburetor-top caution identifies an integral throttle-cable connection that can be damaged by trying to separate the cap from the cable.

Water-pump illustrations distinguish the 1986–1988 impeller-and-nut assembly from the 1989 arrangement. Mechanical-seal inspection covers the pump's telltale hole, alongside radiator leak diagnosis.

Steering, Rear Axle, and Pro-Link Suspension

Steering coverage includes toe-in adjustment, camber/caster inspection, and front-arm bushing and spherical-bearing differences. Rear-axle instructions distinguish actual fastener torque from the wrench reading when the lock-nut adapter changes leverage.

For the nitrogen-charged rear shock, the manual covers reservoir and compression-valve service, oil bleeding, and recharging. Detailed rider-specific preload and damping setup is referred to the owner's manual.

Brake Service and Electrical Troubleshooting

Brake sections give caliper-piston and master-cylinder inspection limits, plus parking-brake mechanism drawings. Follow the manual's precautions for potentially asbestos-containing brake dust and ventilation during engine testing.

The ignition troubleshooting chart links weak-spark symptoms to connector, coil, pulse-generator, and ground checks. Its connector tests exclude the CDI timing-advance function; ignition timing is factory set and nonadjustable.

Cable and harness routing drawings and ignition-timing views support electrical diagnosis. Maintenance schedules and a competition-use replacement table distinguish routine service from race-use requirements.

A Preview of Top-End and Ignition Specifications

These are a few examples from the engine assembly and maintenance data.

Cylinder-head nuts are specified at 24–29 N·m (17–21 ft-lb). The cylinder-to-piston table separates the standard clearance of 0.060–0.080 mm from the 0.14 mm service limit.

For the listed spark plugs, the maintenance section gives a gap of 0.7–0.8 mm (0.028–0.031 in).

PDF Search, Navigation, and Page Count

Search and diagram detail: OCR text is available from PDF page 127 onward, with incomplete recognition of diagram labels; the earlier pages are not text-searchable. There are 19 embedded bookmarks. Small wiring labels need zooming, and some remain blurred or overlapped. Printed pages 10-9/10-10 appear before 10-7/10-8.

A single, printable 224-page PDF in English. The total includes the cover, safety notice, contents page, one blank page, and six memo pages.