1986 Honda CT110 Service Manual

The 1986 Honda CT110 is a rugged utility motorcycle featuring a 105cc four-stroke single-cylinder engine, semi-automatic transmission with 4 speeds, dual-purpose tires, rugged suspension, and versatile cargo capabilities. Below are key sections for maintenance procedures, specifications, troubleshooting, and repair guidelines.

General Information

Key components: 105cc OHC engine, semi-automatic transmission, CDI ignition system, front and rear drum brakes.

Maintenance Schedule

Regular maintenance intervals for optimal performance and longevity.

1. Every 300 miles: Check engine oil level, tire pressure, chain tension
2. Every 600 miles: Change engine oil, clean air filter, inspect brakes
3. Every 1,200 miles: Replace spark plug, check valve clearance
4. Every 2,400 miles: Replace air filter element, inspect carburetor
5. Every 4,800 miles: Replace brake shoes, inspect wheel bearings

WARNING! Always perform maintenance on level surface with engine cool. Use proper safety equipment.

Engine Service

Engine maintenance procedures and specifications.

1. Oil Change: Drain plug located bottom of engine case, refill with 1.0 quart SAE 10W-40
2. Valve Clearance: Intake 0.002 in (0.05 mm), Exhaust 0.003 in (0.08 mm)
3. Spark Plug: NGK D8EA, gap 0.024-0.028 in (0.6-0.7 mm)
4. Compression: Standard 142-171 psi, minimum 114 psi
5. Cylinder Bore: Standard 2.520 in (64.0 mm), maximum oversize 0.020 in

CAUTION! Ensure engine is cool before servicing. Torque cylinder head bolts to 20 ft-lbs.

Transmission & Clutch

• Transmission Type: 4-speed constant mesh
• Oil Capacity: 0.8 US qt (0.75 liter)
• Oil Type: SAE 10W-40 motorcycle oil
• Shift Pattern: N-1-2-3-4 (semi-automatic)
• Clutch Type: Wet multi-plate
• Primary Reduction: 4.117
• Final Reduction: 2.500
• Gear Ratios: 1st: 3.272, 2nd: 1.937, 3rd: 1.350, 4th: 1.043

Fuel System

Carburetor specifications and maintenance procedures.

Carburetor: Keihin PB12A, main jet #68, slow jet #38, float level 0.98 in (25 mm)

Fuel System: Gravity feed with manual petcock, fuel filter in tank

1. Clean carburetor every 2,400 miles or as needed
2. Check fuel lines for cracks and replace if necessary
3. Adjust idle speed to 1,400 ± 100 rpm
4. Inspect air filter and clean/replace when dirty

Tip: Always use fresh fuel and stabilize if storing more than 30 days.

Electrical System

Supports 6V electrical system with CDI ignition.

1. Battery: 6V 4Ah, maintain fluid level between lines
2. Charging System: AC generator, output 0.1 kW at 5,000 rpm
3. Headlight: 6V 25/25W halogen
4. Tail Light: 6V 5/18W
5. Fuse: 10A main fuse under seat
6. Spark Advance: Automatic by CDI unit
7. Wiring: Color-coded harness, inspect for fraying or corrosion

WARNING! Disconnect battery before electrical work. Check all connections for tightness.

Brake System

Drum brakes front and rear with mechanical actuation.

Suspension & Steering

Front: Telescopic fork, oil capacity 4.4 oz (130 cc) per leg

Rear: Dual shocks with 5-position spring preload adjustment

1. Check fork oil level every 2,400 miles
2. Inspect fork seals for leaks
3. Lubricate steering head bearings annually
4. Adjust rear shock preload for load conditions

CAUTION! Do not overtighten steering head bearings. Check for smooth operation.

Wheels & Tires

Spoke wheels with tube-type tires.

Tire Pressure: Front 22 psi, Rear 29 psi (solo riding)

Troubleshooting

Reset: None required for mechanical systems.

Service: Contact authorized Honda dealer for professional service

Specifications

• Overall Length: 78.0 in (1980 mm)
• Overall Width: 31.5 in (800 mm)
• Overall Height: 41.5 in (1055 mm)
• Wheelbase: 49.0 in (1245 mm)
• Ground Clearance: 7.1 in (180 mm)
• Seat Height: 30.5 in (775 mm)
• Fuel Consumption: 100+ mpg (estimated)
• Top Speed: 55 mph (89 km/h)