This kit works with the 157QMJ GY6 150cc Chinese engine with a 76mm bolt pattern.

76mm x 54mm bolt pattern

You will need to machine your case to make room for the larger cylinder.

63mm Big Bore Cylinder Kit for 125cc - 150cc GY6 Scooters, ATVs, and Go Karts

INCLUDES:

Cylinder, Piston, Piston Rings, Circlips, Wrist Pin, and Gaskets

An outstanding 180cc big bore cylinder kit for GY6 based 125/150cc engines. This cylinder kit fits on many air-cooled 4-stroke 125-150cc Kymco, REX and Keeway scooter engines and most Chinese import 125/150cc vehicles (scooters, quads, and buggies).

**NOTE: YOU WILL HAVE TO BORE OUT YOUR ENGINE CASE TO COMPLETE INSTALLATION**