1988 GL1500 Service Manual

The 1988 GL1500 is a touring motorcycle featuring a 1520cc liquid-cooled horizontally opposed six-cylinder engine, shaft drive, comprehensive instrumentation, integrated luggage system, and advanced touring amenities. This service manual covers maintenance procedures, specifications, troubleshooting, and repair instructions for proper servicing of all major systems including engine, transmission, electrical, suspension, and braking components.

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

General Information

Overview of the 1988 GL1500 Gold Wing including model identification, vehicle identification number locations, and general service precautions.

Component	Description
Engine Type	1520cc liquid-cooled horizontally opposed 6-cylinder
Bore x Stroke	71mm x 64mm
Compression Ratio	9.8:1
Fuel System	Dual CV carburetors
Transmission	5-speed with electric reverse
Final Drive	Shaft drive
Frame Type	Double-cradle steel frame
Suspension Front	41mm telescopic fork
Suspension Rear	Pro-Link single shock
Brakes Front	Dual hydraulic disc
Brakes Rear	Single hydraulic disc

Maintenance Schedule

Recommended service intervals and procedures for optimal performance and longevity.

Every 4,000 miles: Change engine oil and filter
Every 8,000 miles: Check/adjust valve clearances
Every 12,000 miles: Replace air filter element
Every 16,000 miles: Change final drive oil
Every 24,000 miles: Replace spark plugs
Every 2 years: Replace brake fluid
As needed: Check tire pressure and tread depth

WARNING! Always use manufacturer-recommended fluids and follow torque specifications precisely.

Engine Service

Complete engine service procedures including cylinder head removal, valve adjustment, timing belt replacement, and cooling system maintenance.

Valve clearance adjustment: 0.15mm intake, 0.20mm exhaust (cold)
Timing belt replacement: Every 60,000 miles or 5 years
Compression test: Should read 170-200 psi with less than 10% variation
Cooling system: Check radiator cap (13-17 psi), thermostat opening (80-84°C)
Oil capacity: 3.9 liters with filter change

CAUTION! Engine must be cold before performing valve adjustments to prevent inaccurate measurements.

Transmission & Drive System

Transmission service, clutch adjustment, and final drive maintenance procedures.

Transmission Oil: 10W-30 motor oil, 2.3 liters capacity
Final Drive Oil: 80W-90 gear oil, 180ml capacity
Clutch Freeplay: 10-20mm at lever end
Shift Mechanism: Check linkage for smooth operation
Reverse System: Electric motor engagement procedure

Electrical System

Battery maintenance, charging system testing, ignition system service, and lighting circuit diagnostics.

Battery: 12V 20Ah, specific gravity 1.280 at 20°C

Charging System: Output 350W at 5000 RPM, regulated voltage 14.0-15.0V

Ignition System: Electronic ignition, timing fixed, advance controlled electronically

Starter: 0.9kW reduction type, draw current 90A max

Fuses: Main 30A, Headlight 15A, Signal 10A, Ignition 10A

Fuel System

Carburetor service, fuel pump testing, and fuel delivery system maintenance.

Carburetor synchronization: Use vacuum gauges, adjust to equal vacuum
Float level: 15.5mm from carburetor body
Fuel pump pressure: 2.5-3.5 psi
Idle speed: 850 ± 50 RPM (warm)
Fuel filter replacement: Every 24,000 miles

Tip: Always use fresh fuel and stabilizer for extended storage periods.

Suspension & Steering

Front fork service, rear shock maintenance, steering head bearing adjustment, and wheel alignment.

Fork oil: 10W, 545ml per leg
Steering head bearing torque: 45-50 Nm
Rear shock preload: 5-position adjustable
Wheel alignment: Check for proper tracking
Tire pressures: Front 36 psi, Rear 41 psi (cold)

WARNING! Always support motorcycle securely when working on suspension components.

Braking System

Brake pad replacement, rotor inspection, brake fluid service, and hydraulic system maintenance.

Component	Specification
Front Brake Pad Wear Limit	1.0mm minimum thickness
Rear Brake Pad Wear Limit	1.0mm minimum thickness
Front Rotor Thickness	4.8-5.2mm (service limit 4.5mm)
Rear Rotor Thickness	5.8-6.2mm (service limit 5.5mm)
Brake Fluid	DOT 4

Specifications

Overall Length: 2635mm
Overall Width: 980mm
Overall Height: 1475mm
Wheelbase: 1690mm
Seat Height: 740mm
Ground Clearance: 135mm
Curb Weight: 385kg
Fuel Capacity: 22 liters
Fuel Consumption: 45 mpg (highway)

Troubleshooting

Symptom	Possible Cause	Corrective Action
Hard starting	Weak battery, fuel delivery	Check battery voltage, fuel flow, spark quality
Poor idle	Carburetor sync, vacuum leaks	Synchronize carburetors, check vacuum lines
Overheating	Coolant level, thermostat	Check coolant, radiator cap, thermostat operation
Electrical failure	Battery, charging system	Test battery, stator output, regulator/rectifier
Brake pulsation	Warped rotors	Measure rotor runout, replace if excessive
Transmission noise	Low oil, worn gears	Check oil level and condition, inspect gears

Wiring Diagrams

Complete electrical schematics for main harness, lighting circuits, ignition system, and accessory connections. Color-coded wiring with connector locations and pin assignments.

Note: Always disconnect battery before performing electrical work to prevent short circuits.

Service Support: For technical assistance contact authorized Honda service centers or refer to Honda service bulletins.