Abstract: A rotary transmission leadthrough as part of a vehicle tire pressure regulating system, comprising a rotor structural group that can be connected in a torque-connected manner to a shaft of the vehicle which supports a wheel, and a stator structural group stationarily mounted opposite the rotary movement of the rotor structural group. A sealable conduit between the rotor structural group and the stator structural group is a path for transferring gas from the stator structural group to the rotor structural group and/or the inverse to regulate tire pressure. The rotor structural group is multipartite. A first rotor part is a closed annular body that can be pushed on the vehicle shaft. A second rotor part mounted axially to the first rotor part and connected to it in a torque-connected manner is designed as a tensioning ring for connecting the rotor structural group to the vehicle shaft in a torque-connected manner.

Abstract: A four stroke internal combustion engine having cooling system for cooling the engine is disclosed. The cooling system includes a closed loop cooling system for cooling at least a portion of the engine. The cooling system also includes an open loop cooling system for cooling at least a portion of the engine. The open loop cooling system uses coolant from an external source (e.g., a body of water) to cool the engine.