This is a brand new 440cc bolt on cylinder kit. It includes a brand new 89mm cylinder, big bore piston kit, head gasket and base gasket with 2 o-rings. This is a true bolt on kit, no machining or custom work required, just remove your old cylinder/piston and install this kit! Quality and performance guaranteed! Complete 440cc big bore cylinder kit Improved casting design with larger cylinder liner Bore and stroke 89.00mm x 70.00mm 440cc displacement / 10:1 piston compression Includes moly coated piston kit, gasket kit and more direct fit parts for a hassle free installation, no body modifications required