Cylinder Stock Bore Race Kit for 2-StrokeAluminum cylinder is nickel carbide coated designed with larger water jacketsSpecially designed, high performance, hard anodized power valves (cannot use OEM)There is an aluminum cylinder head with a removable bronze dome allowing for a higher compression ratio and anti-detonation features (except where noted)Kit also includes a Cast-Lite flat top piston kit, and an Athena top-end gasket set that includes required seals and hardwareBolt on; no matching required except where notedYZ125 '97-'98 models require the use of a '99 or newer exhaust pipe and silencer.