Yamaha QT50 QT 50 1979-1992 Workshop Service Manual Repair

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Tipo: Motorcycle

Proveedor:

SKU: 56685

Etiquetas: 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Motorcycle Motorcycles QT 50 QT50 QT50 MA50 Yamaha

Variantes de producto

Descripción

The Yamaha QT50, produced from 1979 to 1992, is a lightweight, step-through moped designed for urban commuting and recreational use. This iconic model, known for its user-friendliness and affordability, was a popular choice in its segment, competing with other 50cc two-stroke mopeds of the era. Engineered with a reliable air-cooled, two-stroke engine and an automatic Continuously Variable Transmission (CVT), the QT50 offers a smooth and accessible riding experience. Its robust steel frame and practical design, including ample ground clearance and a manageable wet weight, contribute to its enduring appeal among enthusiasts and owners. This comprehensive workshop service manual provides in-depth technical information for the Yamaha QT50, covering all model years from 1979 to 1992. The manual details engine overhaul, transmission servicing, chassis maintenance, brake system repair, and electrical diagnostics, including wiring diagrams. It also outlines routine maintenance procedures, troubleshooting guides for common issues such as carburetor clogging and CVT belt wear, and essential technical specifications. This resource is invaluable for owners, mechanics, and technicians seeking to maintain, repair, and preserve the performance and longevity of their Yamaha QT50.

🏷️ Basic Information

Identification

Make:

Yamaha

Model:

Model Designation:

QT 50

Model Code:

Generation

Production Start Year:

Production End Year:

Codes

Chassis Code Prefix:

👋 Introduction

Market Position

Segment:

Lightweight Moped / Scooter

Target Audience:

Enthusiasts, owners, and mechanics requiring in-depth maintenance and repair information for the Yamaha QT50.

Competitive Analysis

Competitors:

Honda Spree, Suzuki FA50, Tomos Revival, various other 50cc two-stroke mopeds of the era.

Key Features

Vehicle Type:

Step-through moped with automatic transmission.

Manual Value Proposition:

Provides essential, factory-level repair and maintenance data for preserving the longevity and performance of the Yamaha QT50.

📋 Manual Details

Coverage Areas

Covered Model Years:

1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992

Page Count

Estimated Pages:

Manual Type

Type:

Workshop Service Manual / Repair Manual

Language

Language:

English

Format

Format:

PDF Download

📖 Manual Coverage

Systems Covered

Engine:

Complete overhaul, tuning, diagnostics, carburetor, ignition system, cooling system, lubrication.

Transmission:

Automatic CVT (Torque Converter) system, belt replacement, clutch, gear oil.

Chassis:

Frame inspection, suspension (front fork, rear shock), steering system, wheel bearings.

Brakes:

Front drum brake, rear drum brake, brake cable adjustment and replacement, master cylinder (if applicable).

Electrical:

Wiring diagrams, lighting system, ignition coil, battery, charging system (stator, rectifier/regulator), switches, fuses.

Fuel System:

Fuel tank, fuel lines, fuel filter, carburetor (Mikuni VM series).

Body And Frame:

Body panels, seat, handlebars, fenders, fairings, decals, storage compartment.

Procedures Included

Maintenance:

Routine checks, oil changes, spark plug replacement, air filter cleaning/replacement, chain adjustment (if applicable), brake adjustments, lubrication points.

Repair:

Engine rebuild, carburetor overhaul, transmission servicing, brake system repair, electrical component replacement, suspension overhaul.

Troubleshooting:

Diagnostic guides for common problems, symptom-based troubleshooting charts.

Diagnostics:

Engine performance issues, electrical system faults, starting problems.

Technical Depth

Depth:

Comprehensive, covering everything from basic owner maintenance to full engine and transmission rebuilds, including detailed diagnostic procedures and specifications.

📊 Manual Specifications

File Format

Quality:

High-resolution PDF, searchable text, clear diagrams and images.

Print Quality

Usability:

Optimized for digital viewing and printing. Pages can be printed individually or as a complete manual.

Binding Type

Digital Format:

N/A (Digital Download)

Paper Type

Digital Format:

N/A (Digital Download)

⚙️ Engine Specifications

Primary Engine

Type:

Two-stroke, single-cylinder, air-cooled

Displacement:

49.2 cc

Bore:

39.0 mm

Stroke:

41.0 mm

Compression Ratio:

7.2:1

Carburetor Model:

Mikuni VM15SA

Carburetor Specifications:

Main Jet: #82.5, Pilot Jet: #17.5, Needle Jet: 6F52-3, Throttle Valve: #2.0, Air Screw: 1.5 Turns Out

Performance

Horsepower:

Approx. 4.0 HP @ 6500 RPM (Varies slightly by year and market)

Torque:

Approx. 3.3 lb-ft @ 6000 RPM (Varies slightly by year and market)

Fuel System

Fuel Type:

Unleaded gasoline

Fuel Mixture:

Pre-mix: 50:1 ratio (Gasoline to 2-stroke oil)

Oil Type:

Yamaha 2-stroke oil or equivalent API-TC rated oil

🔧 Transmission

Standard

Type:

Automatic Continuously Variable Transmission (CVT)

Drive Belt Part Number:

3X3-17641-00-00

Features

Engagement Type:

Centrifugal clutch with automatic variator.

Gear Reduction:

Reduction gear system for final drive.

📐 Dimensions

Exterior

Overall Length:

Approx. 1650 mm (65 in)

Overall Width:

Approx. 660 mm (26 in)

Overall Height:

Approx. 980 mm (38.6 in)

Wheelbase:

Approx. 1140 mm (44.9 in)

Ground Clearance:

Approx. 100 mm (3.9 in)

Weights

Dry Weight:

Approx. 65 kg (143 lbs)

Wet Weight:

Approx. 70 kg (154 lbs) (with fluids)

Max Load Capacity:

Approx. 90 kg (198 lbs) (rider and cargo)

🛡️ Safety Features

Active Features

Braking System:

Front and rear drum brakes, operated by handlebar levers.

Lighting:

Headlight, taillight, brake light, turn signals (front and rear), instrument panel illumination.

Passive Features

Frame Construction:

Steel frame providing a stable platform.

Tires:

Tubed tires, typically sized 2.50-10 or similar for both front and rear.

💡 Technology Features

Infotainment

Instrument Cluster:

Analog speedometer, odometer, indicator lights for turn signals, high beam, and neutral (if applicable).

Driver Assistance

No electronic driver assistance features.

Connectivity

No connectivity features.

🔧 Maintenance

Service Intervals

Oil Change Frequency:

2-stroke oil reservoir refill as needed, based on oil level indicator.

Spark Plug Replacement:

Every 3,000 km (1,860 miles) or annually, check gap every 1,500 km (930 miles).

Air Filter Cleaning:

Every 1,000 km (620 miles) or annually. Replace as needed.

Transmission Oil Change:

Inspect and change every 6,000 km (3,700 miles) or every 2 years. Use Yamaha Gear Oil GL-4 80W-90.

Cvt Belt Inspection:

Inspect every 3,000 km (1,860 miles). Replace every 6,000 km (3,700 miles) or if signs of wear are present.

Fluid Specifications

Engine Oil:

Yamaha 2-stroke engine oil (50:1 ratio premix)

Gear Oil:

Yamaha Gear Oil GL-4 80W-90

Known Issues

Carburetor Clogging:

Common with older two-stroke engines due to fuel varnish or debris. Requires regular cleaning.

Cvt Belt Wear:

Belts can stretch or fray over time, affecting acceleration and top speed. Regular inspection and replacement are crucial.

Electrical Connections:

Corrosion on connectors can lead to intermittent electrical faults. Cleaning and dielectric grease are recommended.

Exhaust Carbon Buildup:

Two-stroke engines can accumulate carbon in the exhaust port and muffler, leading to reduced performance. Periodic de-carbonizing is beneficial.

📚 Vehicle History

Brand Heritage

Manufacturer:

Yamaha Motor Corporation, established in 1955, with a strong legacy in motorcycles and engines.

Model Evolution

Development:

The QT50 was part of Yamaha's entry into the burgeoning moped market, offering a stylish and user-friendly option for urban commuting and recreational use.

Production

Manufacturing Location:

Primarily Japan

Sales Period:

Produced from 1979 through 1992, making it a long-running model in its class.

🏆 Awards & Recognition

Recognitions

The QT50 was a popular and reliable model, widely recognized for its user-friendliness and affordability within the moped market of its era.