1986 Honda VFR 750 Repair Manual

The 1986 Honda VFR 750 is a sport touring motorcycle featuring a 748cc V4 engine, gear-driven cams, Pro-Link rear suspension, and TRAC anti-dive front forks. This comprehensive repair manual covers maintenance, troubleshooting, engine overhaul, electrical systems, chassis, and specifications for proper servicing of your motorcycle. Below are essential sections for routine maintenance, engine repair, electrical systems, chassis maintenance, and troubleshooting procedures.

1. General Information 2. Maintenance Schedule 3. Engine Repair 4. Electrical System 5. Chassis & Suspension 6. Fuel System 7. Cooling System 8. Transmission 9. Brake System 10. Troubleshooting

General Information

Key components: 748cc liquid-cooled V4 engine, 6-speed transmission, TRAC anti-dive front forks, Pro-Link rear suspension, dual front disc brakes.

Component	Specification
Engine Type	748cc liquid-cooled 90° V4
Bore x Stroke	70.0mm x 48.6mm
Compression Ratio	10.5:1
Fuel System	4x 34mm CV carburetors
Ignition System	CDI electronic ignition
Transmission	6-speed constant mesh
Front Suspension	41mm telescopic fork with TRAC
Rear Suspension	Pro-Link single shock
Front Brakes	Dual 276mm discs
Rear Brake	Single 256mm disc

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Oil change: Every 4,000 miles or 6 months
Oil filter: Replace with every oil change
Air filter: Clean every 3,000 miles, replace every 12,000 miles
Spark plugs: Replace every 8,000 miles
Valve clearance: Check every 8,000 miles
Coolant: Replace every 2 years
Brake fluid: Replace every 2 years
Chain adjustment: Every 600 miles

WARNING! Always use genuine Honda parts and recommended fluids. Work on level surface with proper tools.

Engine Repair

Engine disassembly and reassembly procedures.

Cylinder head removal: Drain coolant, remove cam cover, timing belts, cylinder head bolts
Valve adjustment: Set clearances to 0.15mm intake, 0.20mm exhaust
Piston removal: Remove cylinders after head removal, inspect rings
Crankshaft service: Check bearing clearances, oil passages
Timing belts: Replace every 24,000 miles or 4 years
Clutch replacement: Remove right engine cover, replace plates and springs

CAUTION! Use torque wrench for all critical fasteners. Mark timing belt positions before removal.

Electrical System

Battery: 12V 14Ah maintenance-free
Charging System: Three-phase alternator, 350W output
Starter: Electric starter motor with reduction gears
Ignition: CDI with electronic advance
Lights: 60/55W headlight, 21W turn signals, 5W taillight
Fuses: Main fuse 30A, sub fuses 10A-15A
Wiring: Color-coded harness with waterproof connectors

Chassis & Suspension

Frame, suspension, and steering maintenance procedures.

Front Suspension: TRAC anti-dive system service, fork oil change (486ml per leg), seal replacement. Rear Suspension: Pro-Link linkage lubrication, shock absorber service. Steering: Head bearing adjustment, wheel alignment. Wheels: Spoke tension check, rim runout measurement.

Fuel System

Carburetor service and fuel delivery system.

Carburetor removal: Disconnect throttle cables, fuel lines, vacuum lines
Float level adjustment: 15.5mm from float chamber mating surface
Jet cleaning: Clean all jets with compressed air
Synchronization: Use vacuum gauges for balanced operation
Fuel pump: Test pressure and flow rate
Fuel filter: Replace every 12,000 miles

Tip: Use factory specified pilot screws settings as baseline for tuning.

Cooling System

Liquid cooling system maintenance and repair.

Radiator removal: Drain coolant, disconnect hoses and fan wiring
Thermostat: Test opening temperature (80-84°C)
Water pump: Inspect impeller and seal for wear
Coolant capacity: 2.8 liters with radiator
Fan switch: Test activation temperature (95-100°C)
Hoses: Inspect for cracks and softness
Pressure test: Check system for leaks at 1.1-1.4 bar

WARNING! Never open radiator cap when engine is hot. Use proper coolant mixture.

Transmission

6-speed transmission service and clutch system.

Gear removal: Split crankcases to access transmission components. Shift mechanism: Adjust linkage, inspect shift forks and drums. Clutch: Fiber and steel plate inspection, spring free length measurement. Final drive: Chain adjustment and lubrication.

Brake System

Hydraulic brake system maintenance and repair.

Component	Specification
Front brake pads	Replace when worn to 1mm thickness
Brake fluid	DOT 4, replace every 2 years
Rotor thickness	Minimum 4.0mm front, 4.5mm rear
Master cylinder	Inspect for leaks and corrosion
Calipers	Clean and lubricate sliding pins

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 intake boots
Overheating	Coolant, thermostat	Check coolant level, test thermostat operation
Electrical failure	Battery, charging system	Test battery voltage, alternator output
Brake fade	Fluid, pads, air in system	Bleed brakes, replace fluid and pads
Transmission slipping	Clutch adjustment, worn plates	Adjust cable, inspect clutch components

Technical Support: Contact authorized Honda dealer for complex issues

Parts: Use genuine Honda parts for optimal performance and reliability