1987 Honda TRX250X Service Manual PDF

The 1987 Honda TRX250X is a 246cc four-stroke sport ATV featuring electric start, five-speed transmission with reverse, shaft drive, front and rear suspension, front disc brakes, and rear drum brakes. This service manual covers complete maintenance procedures, troubleshooting, repair instructions, and specifications for the 1987 model year. Below are key sections for safety, maintenance schedules, engine service, transmission, electrical system, and troubleshooting.

1. General Information 2. Maintenance Schedule 3. Engine Service 4. Transmission & Drive System 5. Electrical System 6. Fuel System 7. Suspension & Steering 8. Brakes 9. Troubleshooting 10. Specifications 11. Wiring Diagrams

General Information

Key components: 246cc OHC four-stroke engine, electric starter, five-speed transmission with reverse, shaft drive, front double-wishbone suspension, rear swingarm suspension.

Component	Description
Engine Type	246cc OHC four-stroke single cylinder
Starting System	Electric starter with backup recoil
Transmission	5-speed with reverse
Drive System	Shaft drive
Front Suspension	Double wishbone
Rear Suspension	Swingarm with single shock
Front Brakes	Hydraulic disc
Rear Brakes	Mechanical drum
Fuel Capacity	2.6 gallons (9.8 liters)
Dry Weight	324 lbs (147 kg)

Maintenance Schedule

Regular maintenance intervals for optimal performance and longevity.

Pre-ride inspection: Check tires, brakes, controls, lights, oil level.
Every 100 miles/1 month: Check/adjust drive chain, clean air filter.
Every 600 miles/6 months: Change engine oil and filter, check valve clearance.
Every 1200 miles/12 months: Replace spark plug, check carburetor adjustment.
Every 2400 miles/24 months: Replace air filter element, check wheel bearings.

WARNING! Always perform maintenance on level surface with engine off and cool. Use proper safety equipment.

Engine Service

Complete engine disassembly, inspection, and reassembly procedures.

Cylinder head removal: Remove valve cover, camshaft, cylinder head.
Valve adjustment: Intake 0.004 in (0.10 mm), Exhaust 0.005 in (0.12 mm).
Piston and cylinder: Measure piston clearance, inspect cylinder walls.
Crankshaft and connecting rod: Check bearing clearance, end play.
Oil system: Change oil (1.7 US qt), replace filter every 600 miles.

CAUTION! Torque cylinder head bolts to 20 ft-lb in crisscross pattern. Use new gaskets during reassembly.

Transmission & Drive System

Transmission Type: 5-speed constant mesh with reverse
Gear Ratios: 1st: 2.785, 2nd: 1.777, 3rd: 1.266, 4th: 0.954, 5th: 0.789, Reverse: 3.000
Drive System: Shaft drive with bevel gears
Final Reduction: 3.833 (23/88)
Oil Capacity: 0.53 US qt (0.5 liter) Pro Honda HP4 10W-40
Shift Mechanism: Return-type foot pedal

Electrical System

Complete electrical system specifications and service procedures.

Battery: 12V 8Ah, Charging system: AC magneto, Regulator/Rectifier: Shunt type.

Ignition: CDI electronic ignition, Spark plug: NGK DR8ES-L, Gap: 0.028-0.031 in. Lighting: Headlight 12V 30/30W, Brake light 12V 21/5W, Turn signals 12V 21W. Starting system: Starter motor 0.4 kW, Starter clutch roller type.

Fuel System

Carburetor service and fuel system maintenance.

Carburetor Type: Keihin PD28A
Main jet: #112, Pilot jet: #38
Float level: 0.59 in (15.0 mm)
Idle speed: 1400 ± 100 rpm
Fuel filter: Clean every 1200 miles

Tip: Always drain fuel from float bowl during storage to prevent varnish buildup.

Suspension & Steering

Front and rear suspension service and adjustment procedures.

Front suspension: Double wishbone with hydraulic shocks
Rear suspension: Swingarm with single adjustable shock
Wheel alignment: Toe-in 0-10mm, Camber 0°
Steering head bearing adjustment: Torque to 18 ft-lb
Shock preload: 5-position adjustable rear shock

WARNING! Always support ATV securely with jack stands before suspension work. Never work under unsupported vehicle.

Brakes

Front disc and rear drum brake service procedures.

Front brakes: Hydraulic disc, single piston caliper, Pad thickness limit: 0.08 in (2.0 mm). Rear brakes: Mechanical drum, Lining thickness limit: 0.12 in (3.0 mm). Brake fluid: DOT 4, Replace every 2 years.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, compression	Check fuel flow, spark plug, compression (142 psi min)
Poor performance	Clogged air filter, carb issues	Clean air filter, check carburetor jets
Transmission problems	Low oil, worn gears	Check oil level, inspect shift forks
Electrical issues	Battery, stator, regulator	Test battery voltage, check stator output
Brake problems	Worn pads, air in lines	Inspect pads/shoes, bleed brakes

Reset: Disconnect battery for 30 seconds to reset ECU if applicable.

Service: Contact authorized Honda dealer for complex repairs.

Specifications

Engine: 246cc 4-stroke OHC, air-cooled
Bore x Stroke: 74.0 x 57.8 mm
Compression Ratio: 9.2:1
Carburetor: Keihin PD28A
Ignition: CDI electronic
Transmission: 5-speed with reverse
Final Drive: Shaft
Front Tire: 22x7-10
Rear Tire: 22x10-9
Fuel Capacity: 2.6 gal (9.8 L)

Wiring Diagrams

Complete electrical wiring diagrams for all systems including starting, charging, lighting, and ignition circuits. Color-coded wiring with connector locations and ground points.

Note: Refer to detailed fold-out wiring diagrams in printed manual for full-color schematics and connector identification.