RELIABILITY: Precision-engineered to meet or exceed OEM specifications for the GY6 engine platform, ensuring long-lasting performance and consistent cold starts.

Key Features

• ✔ Direct fit for GY6 50cc (139QMB)
• ✔ 14 Teeth / 63 Teeth configuration
• ✔ Hardened steel construction for durability
• ✔ Smooth centrifugal engagement

Technical Specs

SKU:	SMU5012
Small Gear Teeth:	14
Large Gear Teeth:	63
Shaft Diameter:	~8mm
Engine Type:	GY6 50cc 4-Stroke

Engine / System	Typical Vehicle Brands	Notes
GY6 50cc (139QMB)	TaoTao, Buyang, Coolsport	Standard 4-Stroke Scooter
GY6 50cc (139QMA)	Jonway, Znen, Baotian	Common Chinese Import
50cc Chinese ATV	Kazuma, SunL, Roketa	Electric Start Models

Is this a genuine original part?

This is a premium quality 4Drive Aftermarket replacement part, manufactured to meet or exceed original equipment (OE) standards for fitment and performance.

How do I know if it is compatible?

Check your engine code. If you have a GY6 50cc 4-stroke engine (commonly marked as 139QMB or 139QMA), this is the correct starter drive. Please verify the tooth count matches (14/63) if your model is highly modified.

What are the tooth counts on this unit?

The SMU5012 features a 14-tooth small gear and a 63-tooth large drive gear, which is the standard configuration for 50cc Chinese import scooters and ATVs.