Abstract: A cylinder head for a four-stroke combustion engine includes at least one inlet conduit having a valve and/or slide valve and at least one exhaust conduit situated in the cylinder head. The inlet conduit and the exhaust conduit connect into a single main conduit. The main conduit has an orifice having the shape of an annulus, the axis of which is aligned with the main axis of the cylinder. The orifice of the main conduit is provided with an interior valve seat and an exterior valve seat, on which, in the closed position, is seated a ring-shaped plate of the sole lifting valve. The lifting valve has at least one stem. The exhaust conduit of the cylinder head is directly interconnected to the exhaust branch and includes no valve gear and/or slide valve gear. The size of the orifice flow cross-section area corresponds to the sum of flow cross-sectional areas around and inside the annular plate. A space is provided in an interior area adjacent to the valve seat for a spark plug and/or an injection nozzle.