Athena 70cc Big Bore Cylinder Kit Upgrade for 50cc 2-Stroke Vertical A/C Honda, Kymco Scooters INCLUDES: Upgrades to 70cc Aluminum Construction with Nickel Carbide Plated Bore Cylinder Bore: 47.6mm Cylinder Sleeve Outer Diameter: 53.5mm Wrist Pin Diameter: 12mm Total Piston Height: 49.5mm Compression Height (from center of wrist pin hole to top edge of piston): 26mm COMPATIBILITY: Honda – Elite SA50 2T, Dio SP-SR 50 2T, Dio ZX 50 2T, Shadow 50 2T Daelim – Cordi 50 2T A/C, Message 50 2T A/C, Tapo 50 2T Kymco – Curio 50 2T, DJ 50 2T, Fever 50 2T, KB 50 2T SYM – DD 50 2T, Fiddle 50 2T, Flash/Free 50 2T Other Similar Models that use the VERTICAL engine **