1988 Honda VTR250 Service Manual

The 1988 Honda VTR250 is a 249cc V-twin sport motorcycle featuring liquid cooling, DOHC 4-valve per cylinder configuration, 6-speed transmission, and tubular steel frame. This service manual covers maintenance procedures, specifications, troubleshooting, and repair instructions for proper servicing of the VTR250. Below are key sections for general information, periodic maintenance, engine service, chassis, electrical systems, and troubleshooting.

1. General Information 2. Periodic Maintenance 3. Engine Service 4. Chassis 5. Electrical System 6. Fuel System 7. Cooling System 8. Transmission 9. Brake System 10. Troubleshooting

General Information

Key components: 249cc liquid-cooled 90° V-twin engine, 6-speed transmission, tubular steel diamond frame, front disc brake with dual piston caliper, rear drum brake.

Component	Specification
Engine Type	Liquid-cooled 4-stroke 90° V-twin
Displacement	249cc
Bore x Stroke	60.0 x 44.1mm
Compression Ratio	11.0:1
Valve System	DOHC, 4 valves per cylinder
Carburetion	Dual 32mm CV
Ignition	CDI electronic
Transmission	6-speed constant mesh
Final Drive	#520 chain
Frame Type	Tubular steel diamond

Periodic Maintenance

Regular maintenance intervals and procedures for optimal performance.

Engine Oil: Change every 3,000 miles or 6 months - use 10W-40 motorcycle oil
Oil Filter: Replace with every oil change
Air Filter: Clean every 3,000 miles, replace every 12,000 miles
Spark Plugs: Replace every 7,500 miles - NGK CR7HSA
Valve Clearance: Check every 7,500 miles - intake 0.10mm, exhaust 0.12mm
Chain Adjustment: Check every 500 miles - 20-30mm free play
Brake Fluid: Replace every 2 years - DOT 4

WARNING! Always use genuine Honda parts and specified fluids. Wear protective equipment during maintenance.

Engine Service

Engine disassembly, inspection, and reassembly procedures.

Cylinder Head Removal: Remove camshafts, valves, inspect for wear
Cylinder/Piston: Measure cylinder bore, piston clearance, ring end gap
Crankshaft/Connecting Rods: Check bearing clearance, rod big-end play
Camshaft Chain: Inspect tensioner, guide wear, chain stretch
Clutch: Inspect plates, springs, basket for wear

CAUTION! Torque all fasteners to specified values. Use new gaskets during reassembly.

Chassis

Frame: Tubular steel diamond type - inspect for cracks, alignment
Front Suspension: 37mm telescopic fork - oil capacity 335ml per leg
Rear Suspension: Pro-Link single shock - spring preload adjustable
Front Wheel: 16-inch cast aluminum - runout limit 2.0mm
Rear Wheel: 16-inch cast aluminum - runout limit 2.0mm
Front Tire: 100/80-16 - pressure 28 psi
Rear Tire: 120/80-16 - pressure 32 psi
Steering Head: Tapered roller bearings - adjust for smooth operation

Electrical System

Battery, charging system, ignition, lighting circuits.

Battery: 12V 8Ah - specific gravity 1.280, charging voltage 14.0-15.0V

Charging System: Three-phase alternator - output 14V 25A at 5000 rpm

Ignition System: CDI electronic advance - timing 15° BTDC at 1500 rpm

Spark Plug: NGK CR7HSA - gap 0.7-0.8mm

Bulbs: Headlight 60/55W, Tail/Brake 21/5W, Turn Signal 21W

Fuel System

Carburetor service and fuel delivery system.

Carburetor Removal: Disconnect fuel line, throttle cables, vacuum line
Float Level: Check and adjust to 12.5mm
Pilot Jet: #38 - clean with compressed air
Main Jet: #115 - inspect for clogging
Needle Jet: 4DL16-3 - check for wear
Fuel Filter: Replace if contaminated
Fuel Tank: Inspect for rust, clean as needed

Tip: Use compressed air to clean jets, never wire or drills.

Cooling System

Liquid cooling system maintenance and service.

Coolant Capacity: 1.5 liters - use ethylene glycol antifreeze
Radiator Cap: Pressure 0.9-1.1 kg/cm² - replace if not holding pressure
Thermostat: Opens at 80-84°C - test in hot water
Water Pump: Inspect seal, impeller for damage
Hoses: Check for cracks, leaks, replace if hardened
Cooling Fan: Test operation, motor draws 0.5-0.7A
Bleeding: Fill slowly, run engine to circulate, top up as needed

WARNING! Never open radiator when hot. Coolant is toxic - handle with care.

Transmission

6-speed transmission service and clutch adjustment.

Brake System

Front disc brake and rear drum brake service.

Front Disc Brake: Single 276mm disc, dual piston caliper - pad wear limit 1.0mm

Rear Drum Brake: 130mm diameter - shoe wear limit 1.5mm

Brake Fluid: DOT 4 - replace every 2 years

Brake Lines: Inspect for cracks, replace if damaged

CAUTION! Never use petroleum-based cleaners on brake components.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Hard starting	Weak battery, clogged pilot jet	Charge battery, clean carburetor pilot circuit
Poor idle	Vacuum leak, valve clearance	Check intake boots, adjust valves to specification
Overheating	Low coolant, stuck thermostat	Check coolant level, test thermostat operation
Oil consumption	Worn piston rings, valve seals	Perform compression test, inspect valve seals
Electrical failure	Bad regulator/rectifier	Test charging system output, replace R/R if needed
Transmission slipping	Worn clutch plates	Measure clutch plate thickness, replace if worn
Brake drag	Stuck caliper piston	Clean caliper, rebuild if necessary

Special Tools: Required for specific procedures - refer to tool list

Service: Contact authorized Honda dealer for complex repairs