Cylinder Works began in 2008 as the first aftermarket company to provide O.E. appearing standard bore and overbore cylinders to the powersports industry. Replacement top end gasket set for Cylinder Works cylinder kits. To be used with Cylinder Works Big Bore Kit. Detailed Specifications: +3 mm Big Bore Top End Gasket Kit. Includes head, base, exhaust and cam chain tensioner gaskets.