For GY6 49cc 50cc 139QMB Scooter Moped ATV Sunl Starter Clutch Gear US

Starter Clutch Gear for GY6 49cc 50cc 139QMB Scooter Moped ATV Sunl

This starter clutch gear is a one-way drive component that couples the electric starter to the crankshaft on 4-stroke GY6 139QMB engines, so the starter can crank the engine and then release once it fires.

Overview

This starter clutch gear is made for 4-stroke GY6 49cc and 50cc engines used in scooters, mopeds, and ATVs, including Sunl models. It transmits starter torque to the crank during starting and disengages afterward to protect the starter. A practical replacement for a worn or slipping starter clutch gear in a 139QMB build.

Built For Performance

• One-way sprag clutch engages during starting and releases once the engine runs
• Gear teeth cut to mesh with the GY6 139QMB starter reduction drive
• Hardened wear surfaces for long service life across many start cycles
• Direct-fit replacement for the stock starter clutch gear on 49cc and 50cc GY6 engines
• Mounts on the crankshaft end behind the variator or flywheel

Fits These Machines

• for GY6 49cc 4-stroke scooters
• for GY6 50cc 4-stroke scooters
• for 139QMB equipped mopeds
• for 139QMB equipped ATVs
• for Sunl 49cc and 50cc GY6 models

On-The-Job Use

• Replacing a starter clutch gear that slips, grinds, or will not turn the engine
• Rebuilding GY6 139QMB engines in scooters and mopeds
• Servicing ATVs and Sunl models that run the 49cc and 50cc GY6 engine
• Shop repairs when the starter spins but the engine does not crank

Specs At A Glance

Good To Know

Q: What are the signs of a bad starter clutch gear? A: A whirring or grinding noise at start-up, the starter spinning without cranking the engine, or loss of grip under load are the usual symptoms.

Q: Will this fit a Sunl scooter or ATV with a 139QMB engine? A: Yes, this starter clutch gear is intended for 4-stroke GY6 139QMB engines in the 49cc and 50cc class, so confirm your engine code and model before ordering.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.