1986 Honda ATC 250SX Service Manual

The 1986 Honda ATC 250SX is a three-wheeled all-terrain vehicle featuring a 246cc four-stroke engine, five-speed transmission with automatic clutch, reverse gear, front and rear suspension, shaft drive, and electric start. This service manual covers maintenance, troubleshooting, repair procedures, and specifications for proper operation and longevity of your ATC 250SX.

Features at a Glance

Key components: 246cc OHC four-stroke engine, five-speed transmission with reverse, automatic clutch, shaft drive, front and rear suspension, electric start with backup recoil.

Installation & Assembly

Unpack and inspect all components. Assemble on level surface with proper tools.

1. Handlebar installation: Mount handlebars to triple clamp, tighten bolts to specification.
2. Wheel assembly: Install front and rear wheels, ensure proper tire pressure.
3. Battery connection: Connect positive then negative terminals, secure battery.
4. Fluid check: Verify engine oil level, add recommended 10W-40 if needed.
5. Final inspection: Check all fasteners, controls, and safety equipment.

WARNING! ATC is heavy; use proper lifting techniques. Ensure all fasteners are properly torqued.

First-Time Operation

Perform pre-ride inspection before initial operation.

1. Fuel system: Fill with fresh unleaded gasoline (87 octane minimum).
2. Engine start: Turn key to ON, set choke, press start button.
3. Warm-up: Allow engine to warm for 2-3 minutes before riding.
4. Operation check: Test throttle, brakes, transmission, and steering.
5. Break-in period: Avoid full throttle for first 10 hours of operation.

CAUTION! Always wear proper safety gear including helmet, eye protection, and protective clothing.

Specifications

• Engine: 246cc air-cooled four-stroke OHC
• Bore x Stroke: 74.0mm x 57.8mm
• Compression Ratio: 9.6:1
• Carburetor: 30mm piston-valve type
• Ignition: CDI electronic ignition
• Transmission: 5-speed with reverse
• Final Drive: Shaft drive
• Suspension Travel: Front: 5.1", Rear: 5.9"
• Ground Clearance: 7.3 inches
• Fuel Consumption: Approximately 30 mpg

Controls and Operation

Main controls: Handlebar controls, foot controls, instrument panel.

Handlebar Controls: Throttle, front brake lever, ignition switch, light switch, start button, kill switch. Foot Controls: Gear shift lever, rear brake pedal. Instrument Panel: Speedometer, neutral/reverse indicator lights, fuel gauge.

Operation: Start engine with choke, select gear with shift lever, use automatic clutch for smooth acceleration. Reverse gear engagement requires specific procedure for safety.

Maintenance Procedures

Regular maintenance ensures optimal performance and longevity.

1. Pre-ride inspection: Check tires, controls, lights, fluid levels.
2. Engine oil change: Every 100 hours or 6 months with 10W-40.
3. Air filter service: Clean every 50 hours, replace as needed.
4. Spark plug: Clean and gap every 100 hours, replace every 200 hours.
5. Brake adjustment: Check and adjust brake cables regularly.
6. Chain maintenance: Lubricate drive chain every 10 hours.

Tip: Keep maintenance log to track service intervals.

Engine Service

Detailed procedures for engine maintenance and repair.

1. Valve adjustment: Check and adjust valve clearance every 200 hours.
2. Carburetor service: Clean and adjust carburetor for optimal performance.
3. Compression test: Perform to assess engine condition.
4. Ignition timing: Verify and adjust CDI timing if necessary.
5. Cooling system: Ensure cooling fins are clean and unobstructed.
6. Top end rebuild: Piston and ring replacement procedure.

WARNING! Engine components get extremely hot during operation. Allow proper cooling before servicing.

Transmission & Drive System

Transmission service and shaft drive maintenance.

1. Transmission oil: Change every 200 hours with recommended gear oil.
2. Shift mechanism: Adjust and lubricate shift linkage.
3. Shaft drive: Check drive shaft universal joints for wear.
4. Final drive: Service rear differential unit.
5. Clutch adjustment: Verify automatic clutch operation.
6. Gear selection: Troubleshoot difficult shifting issues.

CAUTION! Transmission contains hot oil under pressure. Drain when cool.

Brake System

Front and rear brake service procedures.

Front Brake: Cable-operated drum brake, adjustment at handlebar and brake plate. Rear Brake: Pedal-operated drum brake with parking brake function. Inspection: Check brake shoes for wear, replace if lining is below minimum thickness. Adjustment: Proper free play adjustment for optimal braking performance.

Safety Information

Always wear DOT-approved helmet, eye protection, gloves, long sleeves, long pants, and over-the-ankle boots. Never carry passengers. Avoid paved surfaces. Never operate under influence of drugs or alcohol. Complete training course before operation. Keep hands and feet away from moving parts.

Troubleshooting

Technical Support: Contact authorized Honda dealer for complex repairs.

Parts: Use genuine Honda parts for optimal performance and safety.