1988 1994 Honda TRX300 Service Manual

The Honda TRX300 is a reliable 282cc four-stroke ATV produced from 1988 to 1994, featuring shaft drive, electric start, reverse gear, and durable suspension system. This comprehensive service manual covers maintenance procedures, troubleshooting, specifications, and repair instructions for the complete TRX300 model range. Below are key sections for safety, technical specifications, maintenance schedules, engine service, transmission, electrical systems, and troubleshooting.

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

General Information

Key components: 282cc OHC four-stroke engine, shaft drive system, electric starter with backup recoil, reverse gear, independent front suspension, and drum brakes.

Component	Description
Engine Type	4-stroke OHC single cylinder
Displacement	282cc
Starting System	Electric with auxiliary recoil
Drive System	Shaft drive
Transmission	5-speed with reverse
Suspension Front	Independent double wishbone
Suspension Rear	Swingarm with dual shocks
Brakes Front/Rear	Drum brakes
Fuel Capacity	3.7 gallons (14 liters)
Dry Weight	Approx. 400 lbs (181 kg)

Specifications

Engine: 282cc air-cooled 4-stroke OHC
Bore x Stroke: 75mm x 64mm
Compression Ratio: 8.5:1
Carburetor: 26mm constant velocity
Ignition System: CDI electronic ignition
Oil Capacity: 2.0 quarts (1.9 liters)
Transmission: 5-speed with reverse
Final Drive: Shaft drive
Tire Size Front: 22 x 8-10
Tire Size Rear: 22 x 10-10
Fuel Type: Regular unleaded (87 octane)

Periodic Maintenance

Regular maintenance ensures optimal performance and longevity.

Every 100 miles/1 month: Check engine oil level, tire pressure, brake operation
Every 600 miles/6 months: Change engine oil and filter, clean air filter, inspect spark plug
Every 1200 miles/12 months: Change final drive oil, inspect brake pads, check valve clearance
Every 2400 miles/24 months: Replace spark plug, clean carburetor, inspect drive shaft

WARNING! Always use Honda Genuine parts and recommended lubricants. Work on level surface with engine off.

Engine Service

Complete engine maintenance and repair procedures.

Valve Clearance: Intake 0.004 in (0.10mm), Exhaust 0.005 in (0.12mm)
Spark Plug: NGK DR8ES-L, gap 0.028-0.031 in (0.7-0.8mm)
Oil Change: Use SAE 10W-40 motorcycle oil, capacity 2.0 quarts
Compression Test: Normal 142-171 psi, minimum 128 psi
Timing Chain: Adjust tensioner every 1200 miles

CAUTION! Allow engine to cool before servicing. Use proper torque specifications.

Fuel System

Carburetor service and fuel system maintenance.

Carburetor Settings: Main jet #112, pilot jet #38, needle clip 3rd position
Float Level: 12.5mm (0.49 in)
Idle Speed: 1200 ± 100 rpm
Fuel Filter: Replace every 2400 miles or if contaminated
Throttle Cable: Adjust for 2-3mm free play

WARNING! Work in well-ventilated area. No smoking near fuel system.

Electrical System

Battery, charging system, and electrical components.

Component	Specification
Battery	12V 14Ah
Charging Output	14V 15A at 5000 rpm
Starter Motor	0.6 kW
Headlight	12V 30/30W
Fuse	Main 20A, Sub 10A

Tip: Check battery terminals for corrosion monthly.

Transmission & Drive Train

Gearbox, clutch, and shaft drive service.

Transmission Oil: SAE 10W-40, capacity 1.6 quarts
Clutch Adjustment: 10-20mm free play at lever
Final Drive Oil: SAE 80W-90 gear oil, capacity 0.26 quarts
Shift Mechanism: Inspect for proper engagement
Drive Shaft: Lubricate splines every 2400 miles

CAUTION! Use only recommended gear oils. Overfilling can cause seal damage.

Suspension & Steering

Front and rear suspension maintenance.

Front Suspension: Independent double wishbone, 5.9 in travel
Rear Suspension: Swingarm with dual shocks, 6.7 in travel
Shock Preload: 5-position adjustable
Steering Stem: Adjust bearing play every 1200 miles
Wheel Alignment: Toe-in 0-10mm

Brakes & Wheels

Brake system service and wheel maintenance.

Brake Shoes: Replace if lining thickness under 1.5mm
Brake Adjustment: Adjust cable free play to 10-20mm
Wheel Bearings: Repack with grease every 2400 miles
Tire Pressure: Front 3.6 psi, Rear 3.6 psi (normal load)
Wheel Nut Torque: 65 ft-lbs (88 Nm)

WARNING! Test brakes after adjustment before riding.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, compression	Check fuel flow, spark plug, compression
Poor performance	Clogged air filter, carb issues	Clean air filter, service carburetor
Electrical failure	Battery, fuse, connections	Test battery, check fuses, clean connections
Transmission issues	Low oil, worn gears	Check oil level, inspect gears
Brakes weak	Worn shoes, adjustment	Replace shoes, adjust cables

Emergency Procedures: Always carry basic tools and know how to perform field repairs.

Wiring Diagrams

Complete electrical schematics for 1988-1994 TRX300 models. Diagrams include color codes, connector locations, and component identification for troubleshooting electrical issues.

Service Support: Contact Honda Customer Service at 1-866-784-1870 or visit www.ahm-ownerlink.com for technical assistance and genuine parts.