1986 Yamaha 4 Zinger Service Manual

The 1986 Yamaha 4 Zinger is a compact ATV featuring a 49cc air-cooled 2-stroke engine, automatic centrifugal clutch, full-time 2WD system, and durable steel frame. This service manual covers maintenance procedures, troubleshooting, specifications, and repair instructions for proper servicing and operation of the vehicle. Below are key sections for safety, specifications, maintenance, troubleshooting, and repair procedures.

General Information

Key components: 49cc 2-stroke engine, automatic transmission, full-time 2WD system, steel frame, front and rear suspension.

Specifications

• Engine: 49cc air-cooled 2-stroke single cylinder
• Bore x Stroke: 40.0mm x 39.2mm
• Compression Ratio: 6.5:1
• Carburetor: Mikuni VM12SC
• Ignition: CDI electronic
• Transmission: Automatic centrifugal clutch
• Final Drive: Shaft drive
• Suspension Travel: Front: 2.4 in, Rear: 2.8 in
• Brakes: Drum brakes front and rear
• Tires: Front: 16x7-7, Rear: 16x8-7
• Dry Weight: 165 lbs (75 kg)

Periodic Maintenance

Regular maintenance schedule for optimal performance and longevity.

1. Pre-ride inspection: Check tires, brakes, controls, and fluid levels
2. Engine oil: Check level before each ride
3. Air filter: Clean every 100 hours or as needed
4. Spark plug: Replace every 200 hours
5. Brake system: Inspect and adjust every 50 hours
6. Drive chain: Lubricate every 20 hours
7. Wheel bearings: Inspect every 100 hours

WARNING! Always perform maintenance in well-ventilated area. Allow engine to cool before servicing.

Engine Service

Engine disassembly, inspection, and reassembly procedures.

1. Cylinder head removal: Remove spark plug, disconnect exhaust, remove head bolts
2. Cylinder inspection: Check for scoring, measure bore wear
3. Piston service: Measure ring gap, check piston clearance
4. Crankcase disassembly: Remove engine from frame, split cases
5. Crankshaft inspection: Check runout, bearing condition
6. Reassembly: Use new gaskets, proper torque specifications

Torque Specifications: Cylinder head: 14 ft-lbs, Crankcase: 7 ft-lbs, Spark plug: 14 ft-lbs

Fuel System

Carburetor service and fuel system maintenance.

1. Carburetor removal: Disconnect fuel line, throttle cable, and vent lines
2. Float level adjustment: Set to 0.63 in (16mm)
3. Jet cleaning: Clean all jets with compressed air
4. Fuel filter: Replace if clogged or damaged
5. Fuel tank: Inspect for rust, clean as needed
6. Oil injection: Check pump operation and lines

CAUTION! Gasoline is highly flammable. Work in well-ventilated area away from ignition sources.

Electrical System

Testing and service of electrical components.

Chassis & Suspension

Frame, suspension, and brake system service.

1. Frame inspection: Check for cracks or damage
2. Front suspension: Inspect bushings, lubricate pivot points
3. Rear suspension: Check swingarm bearings, shock condition
4. Wheel bearings: Replace if excessive play
5. Brake adjustment: Adjust cable tension, check pad wear
6. Steering: Check for play, lubricate headset bearings

Tip: Use thread locker on all critical fasteners during reassembly.

Transmission & Drive

Automatic transmission and drive system service.

1. Centrifugal clutch: Inspect shoes for wear
2. Drive shaft: Check universal joints for play
3. Final drive: Check gear oil level and condition
4. Chain adjustment: Proper tension 0.8-1.2 in free play
5. Sprockets: Replace if teeth are hooked or worn

WARNING! Transmission contains hot oil. Allow to cool before servicing.

Troubleshooting

Service Note: Always refer to torque specifications during reassembly.

Wiring Diagrams

Complete electrical schematics for troubleshooting and repair.

• Main harness routing and connections
• CDI ignition system wiring
• Lighting circuit diagrams
• Charging system schematic
• Ground point locations

Note: Use multimeter for voltage and continuity testing. Refer to color codes in diagrams.