Grand Rapids Scooter's Universal Parts 50mm Big Bore Cylinder Kit for 50cc 4-stroke QMB139 engines. Upgrades to 83cc based on a stock stroke of 42mm! Includes cylinder, piston, pin, circlips, rings, head gasket and base gasket.

Supported Models: Bintelli, Tao Tao, Peace Sports, Wolf, Schwinn, Puma, SYM, Alliance, Motorino, and Kymco.

Specifications:

• Upgrades to 83cc!
• Bore: 50mm
• Overall Height: 70mm
• Cylinder Sleeve Outer Diameter: 52.6mm