GY6 / QMB Engines Clutch Retaining Nut

Clutch Retaining Nut for GY6 and 139QMB Engines

This clutch retaining nut secures the rear clutch assembly to the pulley shaft on GY6 and 139QMB scooter engines. It is designed to suit several setups, including 50cc, 125cc, and 150cc models. If you are looking at parts for a smaller displacement machine, you can browse our GY6 50cc scooter parts to see what else is available for your drivetrain.

Signs It May Need Replacing

Think about swapping out the clutch retaining nut if the rear clutch is acting up or if you have the pulley apart for service. These nuts can wear or get damaged over time, which may lead to the clutch slipping out of engagement. Checking it during routine maintenance can help you avoid bigger problems later.

What You Need for Installation

A 39mm socket is needed to tighten this nut, and an impact tool works best. Using the right tools helps the nut seat firmly for dependable operation. Follow the torque figures for your particular engine so the nut is neither overtightened nor stripped.

Specifications

• MPN: 623A19
• Thread Size: M28 x 4mm pitch
• Engine: GY6 50cc / 125cc / 150cc, 139QMB 49cc / 50cc
• Application: Driven pulley / clutch assembly
• Required Tool: 39mm socket (impact recommended)
• Made in: Taiwan
• Fits: GY6 150cc (157QMJ) driven pulley clutch assembly; GY6 50cc/125cc and 139QMB engines also listed

Compatibility

Compatible with:

• GY6 150cc (157QMJ)
• GY6 50cc / 125cc (139QMB 49cc / 50cc also listed)

Selection tip: Pair a 39mm socket (impact recommended) with an M28 x 4mm pitch thread to make sure the nut matches your clutch shaft.

Location in assembly: Part #6 on the driven pulley diagram for the GY6 150cc (157QMJ).

Browse related parts: GY6 50cc Scooter Parts (139QMB) · GY6 Scooter Parts · Scooter Clutches & Clutch Springs · Scooter Bolts, Screws & Hardware · Scooter Parts