13.5:1 CP or JE forged piston. Cometic top end gasket kit. This is a bolt on kit and the piston uses pump or race gas. We ALWAYS STRONGLY recommend that this be installed by a qualified mechanic with experience doing this type of work.The item "01-13 YZ250F YZF250 YZ WR 250F 80 mil Big Bore Top End Rebuild Kit JE CP Wiseco" is in sale since Wednesday, February 20, 2019. This item is in the category "eBay Motors\Parts & Accessories\Motorcycle Parts\Engines & Engine Parts\Big Bore & Top End Kits". The seller is "bpracingatv" and is located in Upland, California. This item can be shipped worldwide.