GY6 63mm 180cc Big Bore Kit - ProBld

If you are looking for a really really nice 63mm 180cc big bore kit for your GY6 A (54mm stud spacing), this is the ticket! This is a forged piston with a ceramic coated cylinder to keep it cool. We definitely recommend an oil cooler for this set up. If you want to make it a 190cc add a 3mm stroker crank. We even have the option for a 205cc kit here: CLICK HERE IMPORTANT NOTE: Your engine cases will need to be bored out. This is not a drop in kit. You will need this tool CLICK HERE. In order to bore the cases, the crank shaft has to be removed. Definitely add a high volume oil pump to this set up CLICK HERE.