1988 Harley Sportster 1200 Service Manual

The 1988 Harley-Davidson Sportster 1200 is a classic American motorcycle featuring a 1200cc V-twin Evolution engine, 4-speed transmission, belt final drive, and iconic cruiser styling. This service manual covers maintenance procedures, specifications, troubleshooting, and repair instructions for proper upkeep of your motorcycle. Below are key sections for safety, maintenance schedules, engine service, electrical systems, and troubleshooting.

1. Features and Specifications 2. Safety Precautions 3. Maintenance Schedule 4. Engine Service 5. Transmission and Clutch 6. Electrical System 7. Fuel System 8. Brakes and Wheels 9. Troubleshooting 10. Torque Specifications 11. Wiring Diagrams

Features and Specifications

Key components: 1200cc Evolution V-twin engine, 4-speed transmission, belt drive, front and rear suspension, electrical system.

Feature	Description
Engine Type	4-stroke, 45° V-Twin Evolution
Displacement	1200cc (73.3 cu in)
Bore x Stroke	88.8mm x 96.8mm
Compression Ratio	9.0:1
Transmission	4-speed, constant mesh
Final Drive	Belt
Fuel Capacity	2.25 gallons (8.5 liters)
Oil Capacity	3 quarts (2.8 liters)
Ignition System	Electronic
Front Brake	Single disc
Rear Brake	Drum

Safety Precautions

Always follow safety procedures when servicing your motorcycle.

Work in well-ventilated area: Avoid inhaling exhaust fumes or chemical vapors.
Use proper tools: Ensure all tools are in good condition and appropriate for the task.
Support motorcycle securely: Use center stand or proper lift when working underneath.
Disconnect battery: Before electrical work to prevent shorts or shocks.
Wear protective gear: Safety glasses, gloves, and appropriate clothing.

WARNING! Gasoline is highly flammable; keep away from sparks, flames, and heat sources. Engine and exhaust components become extremely hot during operation.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Pre-ride inspection: Check tires, brakes, lights, and fluid levels before each ride.
Every 500 miles: Check and adjust chain tension, inspect brakes.
Every 2,500 miles: Change engine oil and filter, inspect spark plugs.
Every 5,000 miles: Clean and adjust carburetor, check valve clearance.
Every 10,000 miles: Replace air filter, inspect wheel bearings.
Seasonal: Check battery, change brake fluid annually.

CAUTION! Failure to follow maintenance schedule may result in component failure and unsafe riding conditions.

Engine Service

Oil Change: Use SAE 20W-50 motorcycle oil; replace filter every change.
Valve Adjustment: Check clearance every 5,000 miles; intake 0.003-0.005 in, exhaust 0.005-0.007 in.
Spark Plugs: Champion RA8HC or equivalent; gap 0.038-0.043 in.
Compression Test: Should read 120-150 psi with throttle open.
Carburetor: Keihin CV 40mm; idle mixture and speed adjustment procedures.
Cooling: Air-cooled; ensure fins are clean and unobstructed.

Transmission and Clutch

4-speed transmission with wet multi-plate clutch.

Transmission Oil: Use Harley-Davidson Formula+ or equivalent; capacity 1 quart (0.95 liters).

Clutch Adjustment: Proper free play at lever 1/8-1/4 inch. Shift Mechanism: Inspect shift linkage for wear. Primary Chain: Check tension periodically.

Electrical System

12-volt system with battery, alternator, ignition, and lighting circuits.

Battery: 12V, 19 amp-hour; maintain proper fluid level.
Charging System: Alternator output 19 amps at 2000 RPM.
Ignition: Electronic ignition module; no points to adjust.
Lights: Headlight, taillight, brake light, turn signals.
Fuses: Main fuse 30 amp; accessory fuses in fuse block.

Tip: Keep battery terminals clean and tight; check connections regularly.

Fuel System

Gravity-fed fuel system with single carburetor.

Fuel Tank: Remove for access to internal components.
Fuel Lines: Inspect for cracks or deterioration; replace if necessary.
Carburetor: Keihin CV; clean jets and passages regularly.
Air Filter: Paper element; replace when dirty or clogged.
Fuel Filter: In-line filter; replace annually or as needed.
Fuel Pump: Mechanical type; check operation if fuel delivery issues occur.

WARNING! Gasoline is extremely flammable. Work in well-ventilated area away from ignition sources.

Brakes and Wheels

Front disc brake and rear drum brake system.

Front Brake: Single piston caliper; check pad wear and rotor condition. Rear Brake: Adjust cable tension for proper operation. Tires: Front 100/90-19, Rear 130/90-16; maintain proper inflation. Wheels: Spoke wheels; check spoke tension and true regularly.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, or compression	Check fuel flow, spark plugs, battery charge, and compression.
Poor performance	Carburetion or ignition	Clean carburetor, check spark plugs, adjust valves.
Electrical failure	Battery or charging system	Test battery, check alternator output, inspect wiring.
Transmission issues	Oil level or clutch	Check transmission oil level, adjust clutch, inspect shift mechanism.
Brake problems	Pads, fluid, or adjustment	Inspect brake pads, check fluid level, adjust rear brake.

Reset: For electronic issues, disconnect battery for 5 minutes to reset system.

Service: Contact authorized Harley-Davidson dealer for complex repairs.

Torque Specifications

Component	Torque Value
Spark Plugs	18-20 ft-lbs
Oil Drain Plug	14-21 ft-lbs
Axle Nuts	50-70 ft-lbs
Cylinder Head Bolts	18-22 ft-lbs
Wheel Nuts	40-60 ft-lbs
Sprocket Nut	80-100 ft-lbs

Wiring Diagrams

Complete electrical schematics for troubleshooting electrical issues.

Color-coded wiring diagrams show connections for ignition system, charging circuit, lighting, and accessories. Refer to specific sections for detailed component locations and testing procedures.

Note: Always disconnect battery before working on electrical system to prevent shorts or damage to components.