Segment:
Lightweight scooter, popular for urban commuting and recreational use.
Competitors 1984:
Competed with other 50cc scooters from brands like Honda (e.g., Spree, Aero), Tomos, and Italian marques of the era.
Vehicle Features:
Compact design, fuel efficiency, easy operation, and Yamaha's reputation for reliability.
Value:
An essential resource for owners and mechanics to maintain, repair, and restore the Yamaha QT50, ensuring longevity and optimal performance.
Engine:
Detailed coverage of the 2-stroke engine, including disassembly, inspection, assembly, and tuning.
Fuel System:
Carburetor service, fuel delivery, and fuel tank maintenance.
Ignition System:
Ignition timing, spark plug specifications, and electrical component testing.
Transmission Drive:
Automatic transmission (V-belt type) service, clutch operation, and drive belt inspection/replacement.
Chassis Suspension:
Front fork overhaul, rear shock absorber service, and frame inspection.
Brakes:
Front and rear brake system maintenance, adjustment, and component replacement.
Electrical System:
Wiring diagrams, lighting system, battery maintenance, and basic electrical troubleshooting.
Bodywork Cosmetics:
Panel removal/installation, fairing care, and cosmetic refurbishment tips.
Routine Maintenance:
Oil changes, filter replacements, spark plug checks, chain/belt adjustment, and lubrication.
Troubleshooting:
Diagnostic procedures for common running issues, electrical faults, and mechanical problems.
Rebuilding Overhaul:
Comprehensive instructions for engine rebuilds, carburetor overhauls, and suspension component refurbishment.
Adjustments:
Carburetor tuning, brake lever adjustment, and throttle cable free play adjustments.
Specifications:
Torque specifications, clearances, and adjustment settings for all major components.
Depth:
Extensive, covering from basic upkeep to complete engine and transmission rebuilds.
Format Details:
If digital, typically a searchable PDF with high-resolution diagrams. If print, expected to be professionally bound.
Quality:
High-quality printing with clear, legible text and detailed, easy-to-follow diagrams and illustrations.
Binding:
Likely comb binding or saddle stitch for digital prints; professional binding for physical copies.
Paper:
Durable paper stock suitable for workshop environments, resistant to grease and oil.
Engine Type:
2-Stroke, Air-Cooled, Single Cylinder
Displacement:
49cc (approx.)
Bore X Stroke:
Specifications available in the manual.
Compression Ratio:
Specifications available in the manual.
Power Output:
Approx. 3.5-4.0 HP (at specified RPM). Exact figures in manual.
Torque:
Specifications available in the manual.
Carburetor Model:
Likely a Mikuni VM or similar, specific model number in manual.
Fuel Type:
Unleaded gasoline, typically mixed with 2-stroke oil (e.g., 50:1 ratio).
Oil Delivery:
Autolube (oil injection system) or manual premix depending on specific variant; manual will clarify.
Overall Length:
Approx. 1650mm (65 inches) - specific measurements in manual.
Overall Width:
Approx. 660mm (26 inches) - specific measurements in manual.
Overall Height:
Approx. 1020mm (40 inches) - specific measurements in manual.
Dry Weight:
Approx. 63 kg (139 lbs) - specific weights in manual.
Fuel Tank Capacity:
Approx. 3.0 Liters (0.8 Gallons) - exact capacity in manual.
Front Tire Size:
Typically 2.50-10 or similar.
Rear Tire Size:
Typically 2.50-10 or similar.
Wheel Type:
Spoked wheels with inner tubes.
Safety Standards:
Compliant with all applicable safety regulations for its class and era.
Braking System:
Drum brakes front and rear, requiring proper adjustment and maintenance.
Lighting:
Headlight, taillight, brake light, and turn signals for visibility.
Infotainment System:
Basic analogue speedometer and indicator lights. No advanced infotainment features.
Driver Assistance Features:
None. Focus is on fundamental mechanical operation.
Connectivity Options:
None. Purely mechanical and electrical systems.
Oil Change Interval:
Details for 2-stroke oil and transmission oil (if applicable) will be in the manual. Typically requires periodic checking and topping off for autolube systems.
Spark Plug Service:
Recommended checks and replacement intervals will be specified, usually based on mileage or time.
Drive Belt Inspection:
Regular inspection for wear and proper tension is crucial, with replacement intervals provided.
Two Stroke Oil:
Manual will specify required API service classification and TC-W standards, e.g., Yamalube 2-stroke oil.
Transmission Gear Oil:
If a separate transmission fluid is used, its grade (e.g., SAE 80 or 90) and capacity will be detailed.
Carburetor Clogging:
Common with older 2-stroke engines due to fuel varnish, requiring regular cleaning and carburetor kit replacement.
Autolube System Issues:
Potential for oil pump failure or blockages, leading to engine seizure; manual covers inspection and maintenance.
Drive Belt Wear:
Can stretch or fray over time, affecting acceleration and top speed; manual guides replacement.
Cooling System Performance:
Air-cooled, but proper airflow through fins is essential; manual addresses cleaning and inspection.
Yamaha Motorcycles:
Yamaha Motor Corporation has a long-standing reputation for producing high-quality motorcycles and scooters since its inception in the 1950s.
Qt50 Lineage:
The QT50 was part of Yamaha's range of small-displacement scooters, building on previous models and setting the stage for future designs.
Production Era:
Produced through the 1980s, with the 1984 model being a representative example of its generation.
