Abstract: A two-stroke cycle internal combustion engine including a crankshaft, a connecting rod pivotally connected to the crankshaft, a fuel induction system and spark plug or the like. The cylinder has a closed head end and a closed rearward end and a piston within the cylinder defines a combustion chamber as well as a charging chamber. A plurality of radial inlet ports formed in the cylinder wall is normally closed by the piston but is opened to the charging chamber when the piston passes through its top dead center position. A plurality of radial exhaust ports also is formed in the cylinder wall and is normally closed by the piston but opened to the combustion chamber as the piston passes through its bottom dead center position. An axial valve port is formed in the crown of the piston to communicate between the charging chamber and the combustion chamber. An operating rod mounted in the cylinder has a valve head formed on its inner end to close the valve port.