1988 Honda Magna Service Manual
The 1988 Honda Magna is a V4-powered cruiser motorcycle featuring liquid cooling, shaft drive, and a 750cc engine. This service manual covers maintenance procedures, specifications, troubleshooting, and repair instructions for the complete motorcycle system including engine, transmission, electrical, brakes, suspension, and chassis components. Below are key sections for maintenance schedules, specifications, troubleshooting, and repair procedures.
General Information
Key components: V4 750cc liquid-cooled engine, shaft drive system, hydraulic disc brakes, electronic ignition, CV carburetors.
| Component | Description |
|---|
| Engine Type | Liquid-cooled 4-stroke 90° V4 |
| Displacement | 748cc |
| Bore x Stroke | 70.0 x 48.6mm |
| Compression Ratio | 10.5:1 |
| Carburetion | 4x 34mm CV carburetors |
| Ignition | Fully transistorized electronic |
| Transmission | 6-speed constant mesh |
| Final Drive | Shaft drive |
| Brakes | Hydraulic disc front and rear |
| Suspension | Telescopic fork front, dual shocks rear |
Maintenance Schedule
Regular maintenance intervals for optimal performance and longevity.
- Oil Change: Every 3,000 miles or 6 months
- Oil Filter: Replace with every oil change
- Air Filter: Clean every 6,000 miles, replace every 12,000 miles
- Spark Plugs: Replace every 8,000 miles
- Valve Clearance: Check every 16,000 miles
- Brake Fluid: Replace every 2 years
- Coolant: Replace every 2 years or 24,000 miles
- Drive Shaft Oil: Replace every 16,000 miles
WARNING! Always use Honda Genuine parts and recommended fluids. Wear protective equipment during maintenance.
Specifications
- Overall Length: 2,295mm (90.4 in)
- Overall Width: 800mm (31.5 in)
- Overall Height: 1,145mm (45.1 in)
- Wheelbase: 1,610mm (63.4 in)
- Seat Height: 760mm (29.9 in)
- Ground Clearance: 140mm (5.5 in)
- Curb Weight: 249kg (549 lbs)
- Fuel Capacity: 15 liters (4.0 US gal)
- Oil Capacity: 3.2 liters (3.4 US qt) with filter change
- Battery: 12V 14Ah
- Tire Size: Front 110/90-18, Rear 140/90-15
Engine Service
Complete engine maintenance and repair procedures.
- Engine Removal: Disconnect battery, drain coolant, remove exhaust, disconnect wiring and cables
- Cylinder Head: Valve adjustment, camshaft service, head gasket replacement
- Cylinder & Piston: Inspection, measurement, ring replacement
- Crankshaft & Connecting Rods: Inspection, bearing clearance check
- Clutch: Adjustment, plate replacement, spring inspection
- Oil Pump: Inspection and service procedures
- Cooling System: Radiator service, water pump inspection, thermostat replacement
CAUTION! Torque all fasteners to specified values. Use new gaskets during reassembly.
Fuel System
Carburetor service and fuel delivery system maintenance.
- Carburetor Removal: Disconnect fuel lines, throttle cables, vacuum lines
- Carburetor Disassembly: Float bowl removal, jet cleaning, diaphragm inspection
- Float Level Adjustment: Specification 14.5mm ± 1.0mm
- Pilot Screw Adjustment: Factory setting 2-1/8 turns out
- Synchronization: Use vacuum gauges for balanced operation
- Fuel Pump: Pressure test and replacement procedures
- Fuel Filter: Replacement interval every 12,000 miles
Tip: Always use fresh fuel and fuel stabilizer for storage periods over 30 days.
Electrical System
Complete electrical system diagnosis and repair.
- Battery: Maintenance, charging, specific gravity check
- Charging System: Stator testing, regulator/rectifier diagnosis
- Ignition System: Coil testing, pulse generator inspection, timing adjustment
- Starting System: Starter motor service, solenoid testing
- Lighting: Headlight adjustment, bulb replacement, circuit testing
- Switches & Controls: Handlebar switch inspection, cable routing
- Instruments: Speedometer, tachometer, warning lights
WARNING! Disconnect battery before electrical service. Use proper test equipment.
Transmission & Drive
Gearbox and final drive service procedures.
- Transmission Oil: Capacity 2.0 liters, change every 8,000 miles
- Shift Mechanism: Linkage adjustment, drum inspection
- Clutch Cable: Adjustment and lubrication
- Drive Shaft: Universal joint inspection, spline lubrication
- Final Drive: Gear oil replacement, bearing inspection
- Wheel Bearings: Inspection and replacement procedures
Brakes & Suspension
Braking system and suspension maintenance.
- Front Brakes: Pad replacement, caliper service, rotor inspection
- Rear Brakes: Pad replacement, caliper service
- Brake Lines: Inspection for cracks or leaks
- Master Cylinders: Rebuild procedures, fluid replacement
- Front Fork: Oil change, seal replacement, spring inspection
- Rear Shocks: Adjustment, damping inspection
- Steering Head: Bearing adjustment and replacement
CAUTION! Use only DOT 4 brake fluid. Bleed system thoroughly after service.
Chassis & Body
Frame, bodywork, and accessory service.
- Frame Inspection: Crack detection, alignment check
- Body Panels: Removal and installation procedures
- Seat: Removal and latch adjustment
- Footpegs: Inspection and replacement
- Handlebars: Adjustment and control mounting
- Exhaust System: Removal, installation, gasket replacement
Troubleshooting
| Symptom | Possible Cause | Corrective Action |
|---|
| Engine won't start | Fuel, spark, compression | Check fuel delivery, spark plugs, compression test |
| Poor idle | Carb sync, vacuum leaks | Synchronize carburetors, check for vacuum leaks |
| Electrical failure | Battery, charging system | Test battery, check stator output, regulator function |
| Brake pulsation | Warped rotors | Inspect rotors for warpage, replace if necessary |
| Transmission noise | Wear, low oil | Check oil level, inspect gears for wear |
| Overheating | Coolant, thermostat | Check coolant level, test thermostat operation |
Reset: Clear trouble codes by disconnecting battery for 10 minutes.
Service: Contact authorized Honda dealer for technical support.
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