11Pcs Cylinder Piston Kit 47mm Bore Aluminium Alloy Top End Rebuild Set for Jog 50cc 2 Stroke 1E40QMB Engine Item Type: Cylinder Piston Kit Material: Cylinder Bore: 47mm Cylinder Displacement: 70cc Fitment: Fits for Jog 50cc 2 stroke 1E40QMB Engine Replacement for Apirilia Vino, Replacement for JOG CV, Replacement for Polaris, Replacement for ZUMA and many more! Replacement for Minarelli Horizontal type engine. This kit includes things you need to replace your old 50cc cylinder to70cc cylinder.Piston Function: A piston is a cylindrical engine component that slides back and forth in the cylinder bore by forces produced during the combustion process. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft through a piston rod and or connecting rod