1987–1988 Honda TRX 250X FourTrax Service Manual

• Engine removal and installation, cylinder-head overhaul, valve-guide replacement, valve-seat refacing, and camshaft timing.
• QB29 dual-valve carburetor repair, including throttle-valve synchronization, float-level inspection, pilot-screw adjustment, and high-altitude jetting.
• Wet multi-plate clutch, oil pump, and kick-starter disassembly and inspection, plus primary-drive and decompressor mechanism service.
• Crankcase separation, transmission and crankshaft inspection, and reverse-shift mechanism assembly.
• Steering and suspension service, wheel-hub and rear-axle bearing replacement, and drive-chain adjustment.
• Hydraulic brake bleeding, caliper and master-cylinder overhaul, and parking-brake mechanism service.
• CDI ignition diagnosis, alternator and pulse-generator testing, AC-regulator checks, and switch-continuity testing.

Technical Documentation Overview

The 1987–1988 Honda TRX 250X FourTrax service manual is a 229-page PDF covering the 246.4 cc air-cooled four-stroke engine and 5-speed constant mesh transmission with reverse. It is suited to mechanically experienced users equipped for precision inspection and internal repair, since standard workshop procedures are not explained.

The model-identification section shows the locations of the frame and engine serial numbers and carburetor identification number. Routine service covers the air cleaner, valve clearance, cylinder compression, reverse-lock cable, and spark arrester. The maintenance schedule includes provisions for dusty, wet, or muddy riding conditions.

Engine and Fuel-System Repair

The manual distinguishes work that can be done with the engine in the frame from repairs requiring engine removal and crankcase separation. Internal inspection covers piston-ring fit, cylinder wear, connecting-rod clearances, and transmission gears and shift forks. Assembly information addresses crankshaft-to-balancer timing and gear-bushing oil-hole alignment.

Carburetor coverage explains the relationship between the butterfly and piston throttle valves. Its service cautions identify pilot-screw seat damage from overtightening. The decompressor section also identifies insufficient cable free play as a cause of valve damage.

Chassis and Brake Service

For the double-cradle chassis, coverage extends to the double-wishbone front suspension, steering knuckles, tie rods, steering-shaft bearings, and rear swingarm pivots. Tire removal, repair, and mounting procedures accompany the wheel sections. Brake inspection includes disc wear and warpage as well as piston and cylinder measurements.

There are specific limits to component repair: a defective lower front-arm ball joint calls for replacement of the arm assembly. Shock service covers spring removal and damper inspection; the pressurized rear damper is not intended for internal disassembly. Always verify the ATV is securely supported during wheel or suspension work.

Electrical Diagnosis and Illustrated Reference

Ignition-coil and exciter-coil resistance measurements support fault isolation, while ignition timing is checked separately from the CDI connector tests. Symptom-based troubleshooting charts address hard starting, loss of power, poor running at low or high speed, and handling problems.

Illustrated references include the Wiring Diagram, Ignition System Inspection schematic, and Cable & Harness Routing views. Exploded assemblies of the carburetor, clutch, and rear-axle bearing holder show component relationships for disassembly and reassembly. The wiring sheet includes wire-color identification and switch-continuity tables for tracing ignition, lighting, and reverse-indicator circuits.

Specification Highlights

Engine and frame torque tables are backed by component wear limits, clearance specifications, compression-test data, and electrical test values. Oil-capacity specifications distinguish draining, filter replacement, and complete disassembly.

The tool lists identify a float-level gauge (07401-0010000), clutch center holder (07923-KE10000), and ball-joint remover (07941-6920003). They also identify U.S. tool alternatives where specified, allowing the required equipment to be assessed before major repair work.