Athena 70100 Big Bore Cylinder Kit (70cc Bolt On) - 47.66mm Bore. Kits come complete with aluminum cylinder (with a nickel carbide-plated 47.66mm bore), cylinder head, piston assembly (piston, rings, 10mm wrist pin and circlips), carbon reeds and all required top-end gaskets. Replacement top-end gasket kits and piston kits also available separately.