🏷️ Basic Information

Make:

Yamaha

Model:

QT50

Year:

1988

Model Designation:

QT50 'Scoot'

Chassis Code:

LB8

Engine Code:

12R

👋 Introduction

Vehicle Segment:

Lightweight, entry-level scooter, popular for urban commuting and recreational use.

Competitors 1988:

Honda Spree, Suzuki FA50, Tomos Revival.

Engine Type:

Compact, air-cooled, 2-stroke engine known for simplicity and reliability.

Transmission:

Automatic V-belt drive for effortless operation.

Design:

Step-through frame for easy mounting and dismounting, integrated storage.

Maneuverability:

Lightweight and agile, ideal for navigating city traffic.

Benefit To Owner:

Empowers owners to perform maintenance, diagnose issues, and execute repairs, saving time and money.

Benefit To Technician:

Provides definitive factory specifications and procedures for efficient and accurate servicing.

📋 Manual Details

Primary Focus:

Repair and Service

Target Audience:

Professional Technicians and Advanced DIYers

Estimated Pages:

Variable (PDF content, typically 100+ pages for this model)

Type:

Service Manual / Repair Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Engine Mechanical:

Detailed breakdown, inspection, and repair of the 2-stroke engine.

Fuel System:

Carburetor adjustment, cleaning, and overhaul; fuel tank, lines, and filter.

Ignition System:

Spark plug, coil, CDI unit, timing checks and adjustments.

Cooling System:

Air-cooled engine specifications and maintenance.

Transmission Drive:

Automatic transmission (V-belt type), clutch operation, and adjustments.

Brakes:

Front and rear brake systems (drum brakes), adjustment, and maintenance.

Suspension:

Front fork and rear shock absorber inspection, service, and adjustment.

Electrical System:

Lighting, horn, battery, wiring diagrams, and component testing.

Chassis Frame:

Frame inspection, steering system, and wheel bearing maintenance.

Bodywork:

Body panel removal, installation, and general maintenance procedures.

Routine Maintenance:

Oil changes, spark plug replacement, air filter cleaning, brake adjustments, chain lubrication.

Troubleshooting:

Diagnostic flowcharts for common starting, running, and electrical issues.

Engine Rebuild:

Comprehensive instructions for engine disassembly, inspection, component replacement (piston, rings, seals), and reassembly.

Carburetor Overhaul:

Step-by-step guide for cleaning, reassembling, and adjusting the carburetor.

Electrical Diagnostics:

Testing of ignition components, lighting circuits, and charging system.

Suspension Service:

Fork oil replacement and seal inspection; rear shock absorber checks.

Brake Adjustment:

Proper setting of front and rear brake levers and cables.

Wheel And Tire Service:

Tire pressure checks, wheel removal, and bearing lubrication.

Depth Level:

Comprehensive, covering all aspects from basic checks to full engine disassembly and electrical diagnostics.

Diagnostic Tools:

References for basic tools and multimeter usage for electrical testing.

Specifications Detail:

Includes torque values, clearances, fluid capacities, and electrical resistance values.

📊 Manual Specifications

Digital Format:

PDF

Searchability:

Searchable text for quick information retrieval.

Image Resolution:

High resolution for clear diagrams and illustrations.

Layout:

Organized with clear headings, numbered steps, and informative illustrations.

Digital Binding:

N/A (Digital Download)

Digital Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Type:

2-stroke, reed valve, forced air-cooled

Displacement:

49 cc (cubic centimeters)

Bore:

38 mm

Stroke:

43 mm

Compression Ratio:

6.8:1 (typical)

Horsepower:

Approximately 4.0 HP @ 6500 RPM (estimated, may vary by market)

Torque:

Not explicitly specified by Yamaha for this model, but typically low-end torque for scooter applications.

Carburetor Model:

Mikuni VM12SC (typical)

Fuel Type:

Unleaded gasoline (minimum 87 octane recommended)

Fuel Mixture:

Pre-mix (typically 50:1 ratio of gasoline to 2-stroke oil)

Fuel Tank Capacity:

3.0 Liters (0.8 US gal)

2-Stroke Oil Type:

API TC or JASO FD certified 2-stroke oil

Ignition Type:

CDI (Capacitor Discharge Ignition)

Spark Plug Type:

NGK BR7HS or equivalent

Spark Plug Gap:

0.7 - 0.8 mm

🔧 Transmission

Transmission Type:

Automatic V-belt transmission (CVT)

Drive System:

V-belt and centrifugal clutch

Clutch Type:

Centrifugal, automatic

Gear Reduction:

Internal gear reduction for rear wheel drive.

📐 Dimensions

Overall Length:

Approx. 1600 mm (63 in)

Overall Width:

Approx. 680 mm (26.8 in)

Overall Height:

Approx. 1000 mm (39.4 in)

Wheelbase:

Approx. 1135 mm (44.7 in)

Ground Clearance:

Approx. 115 mm (4.5 in)

Dry Weight:

Approx. 65 kg (143 lbs)

Curb Weight:

Approx. 69 kg (152 lbs) with fluids

Max Load Capacity:

Not specified by manufacturer, typically rider plus moderate cargo.

Storage:

Under-seat storage compartment and rear luggage rack provision.

🛡️ Safety Features

Crash Test Ratings:

N/A (Scooters are not typically subjected to formal crash testing like automobiles).

Braking System:

Front and rear drum brakes for reliable stopping power.

Lighting:

Headlight, taillight, brake light, turn signals for visibility.

Horn:

Standard audible warning device.

Frame Construction:

Durable steel frame designed for stability.

Tires:

Tubed tires for basic ride comfort and grip.

Mirrors:

Standard handlebar-mounted rearview mirrors.

💡 Technology Features

Infotainment System:

N/A (Basic scooter with mechanical and electrical systems).

🔧 Maintenance

Initial Inspection:

After 1000 km (600 miles) or 6 months, whichever comes first.

Engine Oil Change Recommendation:

Not applicable (2-stroke pre-mix engine). Check oil reservoir level for oil-injected models if equipped.

Spark Plug Replacement:

Every 3000 km (1800 miles) or as needed based on inspection.

Air Filter Cleaning:

Every 2000 km (1200 miles), replace if damaged.

Drive Belt Inspection:

Every 4000 km (2400 miles) for wear and damage.

Brake Adjustment:

As needed, typically every 2000 km (1200 miles) or before extended storage.

2 Stroke Oil Type:

Yamalube 2M or equivalent API TC / JASO FD rated 2-stroke oil.

Gear Oil Type:

Yamaha Gear Oil 10W-30 or equivalent API GL-4.

Gear Oil Capacity:

Approximately 0.1 Liters (0.1 US qt)

Carburetor Clogging:

Common in older 2-stroke engines due to fuel varnish and debris; requires regular cleaning.

V-Belt Wear:

The automatic transmission belt can wear over time and require replacement.

Ignition Coil Failure:

Can lead to no spark or weak spark issues.

Starter Clutch Wear:

Can cause the electric starter to spin freely without engaging the engine.

📚 Vehicle History

Yamaha Legacy:

Yamaha Corporation, a global leader in musical instruments and audio equipment, has a significant and long-standing presence in the motorcycle and powersports industry.

Qt50 Lineage:

The QT50 was part of Yamaha's series of practical, small-displacement scooters, building on the popularity of earlier models. It represented Yamaha's offering in the highly competitive entry-level scooter market of the late 1980s.

Production Period:

The Yamaha QT50 was primarily produced from the early to mid-1980s, with the 1988 model year being a representative iteration of this generation.

Manufacturing Location:

While Yamaha motorcycles are manufactured globally, specific production details for the QT50 would have originated from their major manufacturing hubs, likely in Japan or potentially other Asian facilities.

🏆 Awards & Recognition

Industry Awards:

N/A (Specific industry awards for this model are not widely documented).

Consumer Ratings:

Generally positive for its class, known for affordability and ease of use.

Emissions Standards:

Compliant with relevant emissions standards for its production year and region.