A system for controlling the temperature of an engine, which includes at least one cylinder. The system includes a turbocharger and at least one air-nozzle. The turbocharger includes exhaust-gas-inlet-port, an exhaust-gas-outlet-port, an air-inlet-port, a compressed-air-outlet-port, a turbine and a compressor. The exhaust-gas-inlet-port is coupled with the exhaust-gas-outlet of the engine. Exhaust gas from the engine rotates the turbine, which rotates the compressor. The compressor draws air from the air inlet port, compresses the air thereby increasing the pressure thereof, and provides the compressed air to the compressed-air-outlet-port. An inlet of the air-nozzle or nozzles is coupled with the compressed-air-outlet-port. The air-nozzle or nozzles are directed toward a respective one of the at least one cylinder, and directs a flow of air toward the respective one of the at least one cylinder.

A system for controlling the temperature of an engine, which includes at least one cylinder. The system includes a turbocharger and at least one air-nozzle. The turbocharger includes exhaust-gas-inlet-port, an exhaust-gas-outlet-port, an air-inlet-port, a compressed-air-outlet-port, a turbine and a compressor. The exhaust-gas-inlet-port is coupled with the exhaust-gas-outlet of the engine. Exhaust gas from the engine rotates the turbine, which rotates the compressor. The compressor draws air from the air inlet port, compresses the air thereby increasing the pressure thereof, and provides the compressed air to the compressed-air-outlet-port. An inlet of the air-nozzle or nozzles is coupled with the compressed-air-outlet-port. The air-nozzle or nozzles are directed toward a respective one of the at least one cylinder, and directs a flow of air toward the respective one of the at least one cylinder.

An improved air-cooled aviation engine includes a compact combustion chamber having an intake valve opening, an exhaust valve opening, and a generally elliptical shape. The elliptical shape has a major axis and a minor axis, with the major axis intersecting both the intake valve opening and the exhaust valve opening. In some examples, the major axis is the same length or shorter than a diameter of a cylinder bore of the engine, and the minor axis is smaller than the major axis. Combustion is thus constrained to a smaller area than that of the cylinder bore.

A front fender is provided in front of an air-cooled engine which is a drive source of a motorcycle. An air introduction hole which opens frontward is formed at a front part of a cylinder head of the air-cooled engine. A space around a plug attachment portion for a spark plug and a space in front of the cylinder head communicate with each other through the air introduction hole. A guide portion for guiding incoming wind toward the air introduction hole is formed at a rear part of the front fender.

A front fender is provided in front of an air-cooled engine which is a drive source of a motorcycle. An air introduction hole which opens frontward is formed at a front part of a cylinder head of the air-cooled engine. A space around a plug attachment portion for a spark plug and a space in front of the cylinder head communicate with each other through the air introduction hole. A guide portion for guiding incoming wind toward the air introduction hole is formed at a rear part of the front fender.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

An air-cooled internal combustion engine including a crankshaft rotating about a crankshaft axis, a first cylinder having a first cylinder head, a second cylinder having a second cylinder head, and a blower assembly. The blower assembly includes a blower housing, a first fan, and a second fan. The first fan is positioned proximate the first cylinder and the second fan is positioned proximate the second cylinder. The first fan and the second fan are each received within the blower housing.

An air-cooled internal combustion engine including a crankshaft rotating about a crankshaft axis, a first cylinder having a first cylinder head, a second cylinder having a second cylinder head, and a blower assembly. The blower assembly includes a blower housing, a first fan, and a second fan. The first fan is positioned proximate the first cylinder and the second fan is positioned proximate the second cylinder. The first fan and the second fan are each received within the blower housing.

An engine apparatus is provided that includes an internal combustion engine and a cooling airflow control subsystem The cooling airflow control subsystem includes an airflow regulator having a first component comprising one or more passageways extending through the first component, and a second component comprising one or more passageways extending through the second component, the second component mounted adjacent the first component; and an actuator operably coupled to the airflow regulator to cause relative rotation between the first and second components when actuated so that the airflow regulator can be altered between: (1) a first state in which the first and second passageways are aligned a first extent to allow a first amount of cooling airflow to reach the engine; and (2) a second state in which the first and second passageways are aligned a second extent to allow a second amount of cooling airflow to reach the engine, the first amount being greater than the second amount.