Abstract: A combustion engine is provided having combustion chambers with reciprocating pistons, intake ports and exhaust ports. Transfer ports may be provided between adjacent combustion chambers to provide a transfer channel that closes during a high load mode of operation of the engine and opens during a partial load mode of operation. Also provided are embodiments in which exhaust ports of adjacent combustion chambers are joined into a common exhaust channel that communicates with an exhaust header of the engine through valve means that open during the high load mode of operation of said engine and close during a partial load mode of operation.

Abstract: A combustion engine is provided having combustion chambers with reciprocating pistons, intake ports and exhaust ports. Transfer ports may be provided between adjacent combustion chambers to provide a transfer channel that closes during a high load mode of operation of the engine and opens during a partial load mode of operation. Also provided are embodiments in which exhaust ports of adjacent combustion chambers are joined into a common exhaust channel that communicates with an exhaust header of the engine through valve means that open during the high load mode of operation of said engine and close during a partial load mode of operation.