The QT50, produced from 1979 to 1992, represents a classic in the lightweight scooter and moped category. Engineered for simplicity, reliability, and fuel efficiency, this model was designed to offer accessible and convenient personal transportation, particularly for urban commuting and recreational riders. Its 49cc two-stroke, air-cooled engine, coupled with an automatic Continuously Variable Transmission (CVT), ensures smooth operation and ease of use. The QT50's design philosophy emphasizes maneuverability and low running costs, making it a popular choice against competitors of its era. This comprehensive workshop repair service manual in English provides detailed technical information essential for maintaining and repairing the QT50 across its production years. It covers all major systems, including the engine, transmission, chassis, brakes, and electrical components, offering step-by-step procedures for routine maintenance, troubleshooting common issues, and performing complete overhauls. The manual also includes crucial technical specifications, torque settings, fluid requirements, and wiring diagrams, making it an invaluable resource for both DIY enthusiasts and professional mechanics aiming to preserve the functionality and longevity of this iconic scooter. 🏷️ Basic Information Identification Make: Yamaha Model: QT50 Model Variant: QT 50 Codes Model Code: QT50 Generation Production Years: 1979-1992 👋 Introduction Market Position Category: Lightweight Scooter / Moped Target Audience: Commuters, recreational riders, vintage scooter enthusiasts. Competitive Analysis Competitors: Honda Spree, Suzuki FA50, Tomos Revival, various other small-displacement mopeds and scooters of the era. Key Features Design Philosophy: Simplicity, reliability, fuel efficiency, ease of operation and maintenance, urban maneuverability. Manual Value Proposition: Provides essential, detailed technical information to maintain, repair, and restore the Yamaha QT50, crucial for preserving its functionality and value. 📋 Manual Details Coverage Areas Covered Years: 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992 Region Coverage: Global (referencing typical Yamaha model specifications) Page Count Estimated Page Count: 300+ Manual Type Type: Workshop Repair Service Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Complete engine overhaul, diagnosis, tuning, lubrication system, cooling system, fuel system, ignition system, exhaust system. Transmission: Automatic transmission (CVT) disassembly, assembly, troubleshooting, fluid service, clutch operation. Chassis: Frame inspection and repair, front fork and suspension servicing, rear shock absorber replacement, steering system maintenance. Brakes: Front and rear brake system servicing, hydraulic system checks, pad replacement, drum adjustment (if applicable), bleeding procedures. Electrical: Wiring diagrams, lighting system, ignition system, charging system, battery maintenance, starter motor, troubleshooting electrical faults. Bodywork: Body panel removal and installation, seat servicing, handlebar replacement, fairing repair (if applicable), cosmetic maintenance. Procedures Included Maintenance: Scheduled maintenance tasks, oil changes, filter replacements, spark plug service, chain adjustment, tire pressure checks, brake adjustments. Troubleshooting: Diagnostic procedures for common starting issues, engine performance problems, electrical faults, braking system anomalies, and transmission engagement. Repair: Step-by-step instructions for engine component replacement, carburetor overhaul, brake system overhauls, suspension rebuilds, and electrical component repair. Specifications: Detailed torque specifications, fluid capacities, wear limits, electrical resistance values, and measurement tolerances. Technical Depth Depth: Comprehensive, covering routine maintenance to complete engine and component overhauls. Suitable for DIY enthusiasts and professional mechanics. 📊 Manual Specifications File Format File Type: PDF Searchability: Typically text-searchable for quick information retrieval. Print Quality Resolution: High-resolution scans of original factory documentation, ensuring clarity of text and diagrams. Binding Type Binding: N/A (Digital Download) Paper Type Paper: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: 2-stroke, air-cooled, reed valve induction Displacement: 49cc Bore X Stroke: 39.0mm x 41.4mm (typical for this engine family) Compression Ratio: 7.2:1 (typical) Carburetor Model: Mikuni VM16-1 (typical, refer to manual for specific variations) Performance Horsepower: Approximately 3.5 - 4.0 HP @ 6000 RPM (estimate, actual may vary) Torque: Not typically published, but designed for low-end urban acceleration. Fuel System Fuel Type: Unleaded gasoline mixed with 2-stroke oil (50:1 ratio common, check manual for precise specification) Fuel Tank Capacity: Approximately 3.5 Liters (0.92 US Gallons) 🔧 Transmission Standard Transmission Type: Automatic (CVT - Continuously Variable Transmission) Clutch Type: Centrifugal automatic clutch Final Drive: Gear reduction Features Operation: Seamless gear ratio changes for optimal engine performance and fuel economy. 📐 Dimensions Exterior Overall Length: Approximately 1765 mm (69.5 inches) Overall Width: Approximately 680 mm (26.8 inches) Overall Height: Approximately 1055 mm (41.5 inches) Wheelbase: Approximately 1240 mm (48.8 inches) Weights Dry Weight: Approximately 73 kg (161 lbs) Gross Vehicle Weight Rating: Refer to chassis plate, typically around 200 kg (440 lbs) 🛡️ Safety Features Ratings Crash Safety: Not applicable in the context of automotive safety ratings. Mopeds generally lack the structural integrity and safety features of motorcycles or cars. Active Features Braking System: Hydraulically operated front disc brake (on some models/years), rear drum brake. Essential for safe operation. Lighting: Headlight, taillight, brake light, turn signals (where equipped), ensuring visibility to others. Passive Features Frame Construction: Steel tube frame providing basic structural support. Tyre Specification: Front: 3.00-10 4PR, Rear: 3.00-10 4PR (typical, check manual...