Model Variant:
SH50 / SH50L / SH50P scooter
Production Years Covered:
1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000
Vehicle Type:
Two-stroke 50cc step-through scooter
Target Audience:
Entry-level riders and commuters seeking an economical 50cc scooter
Primary Use:
Urban commuting and short-distance transportation
DIY Appeal:
Simple two-stroke mechanicals make it a popular first project scooter
Key Strengths:
Lightweight chassis, automatic CVT transmission, low running costs
Competitors of the Era:
Honda Aero 50, Suzuki FS50, Kymco and Taiwanese 50cc scooters
Parts Availability:
Large aftermarket support for Yamaha Minarelli-style 1E40QMB engines
Engine:
49cc air-cooled two-stroke single
Transmission:
Automatic continuously variable transmission (V-belt)
Starting:
Electric and kick start
Brakes:
Front disc, rear drum (varies by year)
Manual Type:
Workshop service repair manual (factory-level)
Delivery:
Instant download
Printable:
All pages printable; print only what you need
Coverage Areas:
All repairs A-Z, mechanical and electrical, all 1987-2000 SH50 models
Illustrations:
Detailed pictures, exploded diagrams and wiring schematics
Engine:
49cc two-stroke single: cylinder head, cylinder, piston, crankshaft, reed valve
Fuel System:
Carburetor, fuel tank, fuel petcock, automatic oil injection pump
Cooling:
Air-cooled shroud and fan cover service
Lubrication:
Autolube oil pump inspection, adjustment and bleeding
Transmission / CVT:
Drive belt, variator, clutch shoes, driven pulley service and specs
Final Drive:
Gear oil change and reduction gear inspection
Ignition / Electrical:
CDI, stator, flywheel, ignition coil, spark plug, switches, wiring diagrams
Charging / Starting:
Battery, voltage regulator, starter motor and starter relay
Suspension:
Front fork seals, oil replacement, rear swingarm and shock
Wheels & Brakes:
Wheel bearings, front disc brake, rear drum brake, cable service
Steering:
Handlebar, steering stem bearings and adjustment
Frame & Body:
Body panel removal, floorboard, seat and luggage hook
Exhaust:
Exhaust pipe and spark arrester cleaning
Lighting:
Headlight, taillight, turn signals and bulbs
Instruments:
Speedometer and indicator lamps
Repair Procedures:
Complete teardown and rebuild, A-Z mechanical and electrical repairs
Maintenance:
Scheduled service, adjustments, tune-up procedures
Diagnostics:
Troubleshooting charts for engine, electrical and CVT faults
Assembly:
Torque specifications, special tools and assembly notes
Illustrations:
Step-by-step photos, exploded views and wiring schematics
Technical Depth:
Factory workshop level with detailed specifications tables
Specifications:
Torque values, clearances, wear limits and fluid capacities
Parts Information:
Exploded diagrams with part identification for ordering
Skill Level:
Suitable for home mechanics through professional technicians
File Format:
PDF (searchable, bookmarked, zoomable)
Compatibility:
Windows, macOS, Linux, iOS, and Android — any device with a PDF reader
Requirements:
A PDF reader application (e.g. Adobe Acrobat Reader, free)
Searchability:
Fully text searchable for fast lookup of any topic
Print Quality:
High-resolution digital pages, printable at full clarity
Binding Type:
N/A — digital download, no physical binding
Paper Type:
N/A — digital download, no physical paper
Primary Engine:
49cc (SH50) air-cooled two-stroke single
Engine Code:
Yamaha 1E40QMB-type (Minarelli vertical pattern)
Bore x Stroke:
40.0 mm x 39.2 mm
Compression Ratio:
Approximately 7.0 : 1
Induction:
Reed valve, CVK-style slide carburetor
Approximate Power:
Around 4-5 hp depending on year and market tuning
Top Speed:
Approximately 30 mph (restricted, US market)
Fuel Economy:
Very high; typically 90-100+ mpg
Fuel Type:
Premix not required - autolube oil injection
Fuel Tank Capacity:
Approximately 1.1 gal (4.2 L)
Carburetor:
Constant-velocity type with automatic choke
Two-Stroke Oil Capacity:
Approximately 1.2 qt (1.1 L) oil tank
Standard Transmission:
Automatic CVT (V-belt) with centrifugal clutch
Optional Transmission:
N/A - single transmission configuration across all years
Final Drive:
Gear reduction unit
Gear Oil Capacity:
Approximately 0.11 L at oil change
Drive Belt:
Replaceable V-belt, periodic inspection required
Clutch:
Dry centrifugal shoe clutch
Variator:
Roller-weighted front pulley; roller weights are a common wear item
Starting:
Electric start with kick start backup
Wheelbase:
Approximately 1,185 mm (46.7 in)
Overall Length:
Approximately 1,700 mm (66.9 in)
Seat Height:
Approximately 700 mm (27.6 in)
Ground Clearance:
Approximately 100 mm (3.9 in)
Curb Weight:
Approximately 60-64 kg (132-141 lb) depending on year
Maximum Load:
Approximately 90 kg (198 lb) rider and cargo
Front Brake:
Disc brake (drum on some early models)
Rear Brake:
Drum brake, right-hand lever operated
Tires:
3.00-10 front and rear tube-type tires
Lighting:
Headlight with high/low beam, taillight, turn signals
Frame:
Steel step-through underbone frame
Ignition Cut:
Kickstand/side-stand safety interlock (some models)
Crash Ratings:
N/A - NHTSA crash testing not conducted for 50cc scooters
Audio System:
N/A - not equipped with audio system
Instrumentation:
Analog speedometer, fuel gauge (some years), indicator lamps
Assistance Systems:
N/A - no electronic rider aids on this era of scooter
Ignition:
CDI electronic ignition
Electric Start:
Electric starter motor with backup kick start
Engine Oil (Autolube):
Check level before every ride; refill as needed
Gear Oil:
Change initially at 1,000 km, then every 6,000 km (approx. 4,000 mi)
Spark Plug:
Inspect/clean every 3,000 km (approx. 2,000 mi); replace as needed
Drive Belt:
Inspect every 6,000 km; replace per wear limits
Air Filter:
Clean every 3,000 km, replace when deteriorated
Two-Stroke Oil:
Yamaha 2-stroke injection oil (API TC grade)
Final Gear Oil:
SAE 10W-30 SE-grade 4-stroke motor oil
Fuel:
Regular unleaded, 87 octane or higher
Fork Oil:
Yamaha fork oil (per manual spec, typically 10W grade)
Known Issues / Common Wear
Common Wear Items:
CVT belt, roller weights, clutch shoes, brake pads/shoes
Known Issues:
Clogged carburetor jets and autolube pump neglect from storage
Electrical:
Corroded connectors and weak batteries on long-stored units
Chassis:
Wheel bearings and steering stem bearings with high mileage
Manufacturer:
Yamaha Motor Co., Ltd., Japan
Heritage:
Yamaha has built small-displacement two-stroke scooters since the 1960s
Introduction:
Razz (SH50) introduced to the US market in 1987
Evolution:
Minor running changes through the 1990s; trim and lighting updates
Production End:
US sales ended around 2001 as four-stroke 50s took over
Production Location:
Yamaha plants in Japan; some assembly in Taiwan
