The 1986 Honda Fourtrax 250 is a reliable all-terrain vehicle featuring a 246cc four-stroke engine, shaft drive system, electric start with backup recoil, independent rear suspension, and durable steel frame. This comprehensive repair manual covers complete maintenance procedures, troubleshooting guides, and step-by-step repair instructions for engine, transmission, electrical systems, brakes, suspension, and chassis components.
Vehicle identification, model variations, serial number locations, and general service precautions.
| Component | Location |
|---|---|
| Frame Serial Number | Right side of steering head |
| Engine Serial Number | Left crankcase cover |
| Model Code | TRX250 |
| Manufacture Date | Stamped on frame tag |
SAFETY FIRST: Always disconnect battery before servicing electrical components. Use proper lifting equipment when working underneath vehicle.
Recommended service intervals and procedures for optimal performance and longevity.
NOTE: Service intervals may vary based on operating conditions and riding style.
Complete engine disassembly, inspection, and reassembly procedures.
TORQUE SPECIFICATIONS: Cylinder head bolts: 20 ft-lbs, Spark plug: 13 ft-lbs, Oil drain plug: 22 ft-lbs
Carburetor service, fuel pump repair, and tank maintenance.
| Component | Specification |
|---|---|
| Carburetor Type | Keihin PD61A |
| Main Jet | #112 |
| Slow Jet | #38 |
| Float Level | 12.5mm |
| Idle Speed | 1400 ± 100 rpm |
WARNING: Always work in well-ventilated area when servicing fuel system. No smoking or open flames.
Wiring diagrams, component testing, and electrical troubleshooting.
TEST PROCEDURES: Stator resistance: 0.1-1.0Ω, Peak voltage: >50V AC at 3000 rpm
Gearbox service, shift mechanism, and final drive maintenance.
SHIFT ADJUSTMENT: Proper freeplay in shift lever is critical for smooth operation.
Hydraulic and mechanical brake service procedures.
| Brake Type | Front | Rear |
|---|---|---|
| System | Dual hydraulic disc | Mechanical drum |
| Pad Material | Semi-metallic | NA |
| Rotor Thickness | 4.0mm service limit | NA |
| Fluid Type | DOT 4 | NA |
BLEEDING PROCEDURE: Always start with rear brake, then front right, then front left caliper.
Front and rear suspension service, steering head bearing adjustment.
ALIGNMENT SPEC: Front toe-in: 0-10mm, Camber: 0° ± 1°
Frame inspection, plastic body panel removal, and accessory installation.
INSPECTION: Regularly check frame for cracks, especially around stress points and welds.
| Problem | Possible Cause | Solution |
|---|---|---|
| Engine won't start | Fuel, spark, compression | Check fuel flow, spark plug, compression test |
| Poor performance | Clogged air filter, carb issues | Clean air filter, inspect carburetor jets |
| Electrical failure | Battery, stator, regulator | Test charging system components |
| Transmission noise | Low oil, worn gears | Check oil level, inspect gears |
| Brake problems | Air in lines, worn pads | Bleed system, replace pads/shoes |
DIAGNOSTIC TIP: Always start with simplest solutions first before major disassembly.