Patent ID: 8490591

Claim:
A valve arrangement contained within a removable cylinder head for a four-cycle internal combustion engine and consisting of a single-lobe unified camshaft driven at half engine speed by a timing chain or timing belt to mechanically operate a single poppet valve to remain fully open during the inlet and exhaust strokes of the piston and remain fully closed during the compression and ignition strokes of the piston and including a passive inlet springless reed valve located in the inlet port, this being opened by the negative pressure created by the downward induction stroke of the piston to enable the inlet of air/fuel whilst drawing-in of air through the exhaust port is prevented by the closed blade of a second passive exhaust springless reed valve located within the exhaust port and held in the closed position under the negative pressure of the same downward stroke of the piston and which opens under the positive pressure created by the upward exhaust stroke of the piston to enable exhaust of the combustion gases, during which period the blade of the inlet springless reed valve located in the inlet port is held in the closed position by the positive pressure created by the same upward stroke of the piston, thus maintaining the appropriate direction of flow through the inlet and the exhaust ports.