FREE SHIPPING THROUGH FRIDAY - ALL ORDERS $50+ Some Restrictions Apply. (Click for details)


Free standard or ground shipping (up to a $15 credit) will automatically be applied at checkout once the qualifying product threshold has been reached.

This offer ends on January 20th, 2017 at 2:00 AM ET.

Applicable to new orders only.

Credit only applies to shipping. Any unused portion of the shipping credit does not apply to a reduction in item price.

US domestic ship to addresses only (excludes Alaska & Hawaii).

Does not include expedited shipping services.
Piston for 50cc GY6 139QMB Scooter Engines
Item: E88-9540
Piston for 50cc GY6 139QMB Scooter Engines
All Images © 2017 Monster Scooter Parts
$ 11 99
Please Select Your Options
Please Select Your Options
Checking Product Status...
Product Features
This is a 39 mm outer diameter piston for 50cc GY6 139QMB scooter engines. The 39 mm piston is a stock size for many Chinese built 50cc GY6 139QMB gas scooter engines, however you should carefully check the dimensions on the Specs tab to see if this is the correct 39 mm outer diameter piston for your scooter.

The Chinese built 50cc GY6 139QMB engine has been in production by many brands and manufacturers over the years, and it is safe to say that these little pistons are powering millions of scooters around the world.
  • Outer Diameter: 39 mm
  • Overall Height: 33 mm
  • Piston Pin: 13 mm
  • Compression Height: 17.25 mm
  • Circlips included