1986 Yamaha QT50 Manual

The 1986 Yamaha QT50 is a 49cc moped featuring a single-cylinder, two-stroke engine with automatic transmission, front and rear drum brakes, and a top speed of approximately 30 mph. This moped is designed for easy operation with minimal maintenance requirements. Below are key sections covering safety, features, operation, maintenance, troubleshooting, and specifications.

Features at a Glance

Key components: 49cc two-stroke engine, automatic centrifugal clutch, kick start, front suspension, rear shock absorbers, speedometer, fuel gauge, and lighting system.

Safety Information

Always wear appropriate safety gear and follow local traffic laws.

1. Wear helmet, eye protection, gloves, and sturdy shoes.
2. Check brakes, tires, and lights before each ride.
3. Do not carry passengers - designed for single rider only.
4. Keep hands and feet away from moving parts.

WARNING! This moped is not designed for highway use. Always ride defensively and be aware of traffic conditions.

Operation Instructions

Starting and operating procedures for the Yamaha QT50.

1. Starting: Turn fuel valve to ON, choke if cold, kick start firmly.
2. Riding: Twist throttle to accelerate; release to decelerate.
3. Braking: Use both front and rear brakes together for smooth stops.
4. Shutting down: Turn ignition switch to OFF position.

CAUTION! Allow engine to warm up before riding, especially in cold weather.

Specifications

• Engine: 49cc two-stroke, air-cooled
• Bore x Stroke: 40.0mm x 39.2mm
• Compression Ratio: 6.5:1
• Carburetor: VM12SH
• Ignition System: CDI
• Transmission: Automatic single-speed
• Final Drive: Chain
• Frame: Steel backbone
• Wheelbase: 45.7 inches
• Seat Height: 29.5 inches
• Ground Clearance: 5.9 inches

Controls and Indicators

Handlebar controls: Right handle - throttle; Left handle - front brake lever. Instrument panel: Speedometer, fuel gauge, ignition switch, headlight switch.

Indicators: Speedometer shows mph/kmh, fuel gauge indicates fuel level, neutral light (if equipped).

Basic controls: Ignition switch (OFF/ON), headlight switch (OFF/LOW/HIGH), horn button, turn signals (if equipped).

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

1. Daily: Check tire pressure, brakes, lights, fuel level.
2. Weekly: Check chain tension and lubrication.
3. Monthly: Check spark plug, clean air filter.
4. Every 6 months: Change transmission oil, check brake pads.
5. Annually: Comprehensive inspection of all systems.

Tip: Keep maintenance records for reference and resale value.

Fuel System

Fuel mixture: 50:1 gas to oil ratio (Yamalube 2-stroke oil recommended).

1. Fuel valve: Turn to ON before starting, OFF when parked.
2. Carburetor: VM12SH with idle speed adjustment screw.
3. Fuel filter: Located in fuel tank; replace if clogged.
4. Fuel lines: Check for cracks or leaks regularly.

WARNING! Use fresh fuel and proper oil mixture to prevent engine damage.

Electrical System

6V electrical system with battery (if equipped) or magneto ignition.

Components: CDI ignition, spark plug (BR6HS), headlight (6V 25/25W), taillight (6V 5/18W), brake light switch.

Charging system: AC magneto provides power for lights and ignition when engine is running.

Brake System

Front and rear drum brakes with mechanical actuation.

1. Front brake: Right handlebar lever actuates front drum.
2. Rear brake: Right foot pedal actuates rear drum.
3. Adjustment: Brake cables can be adjusted at lever and brake arm.
4. Inspection: Check brake shoes for wear every 1,000 miles.

CAUTION! Test brakes at low speed before each ride to ensure proper operation.

Troubleshooting

Service: Consult authorized Yamaha dealer for major repairs.

Parts: Use genuine Yamaha parts for optimal performance and safety.