An apparatus useful in a two-stroke cycle engine or in a pump as a piston disposed within a piston cylinder. The piston cylinder has an intermediate piston cylinder head disposed transversely across the interior of the piston cylinder. The piston has at least one upright extension member extending upwardly from the lower portion. A piston top wall is disposed transversely to the piston cylinder side wall and is attached to the upper portion of the upright extension member of the piston. An upper chamber is defined above the piston top wall. An intermediate chamber is defined immediately below the piston top wall and a lower chamber is defined below the intermediate piston cylinder head. A tube connects the upper chamber with the lower chamber.