Abstract: An internal combustion engine includes an engine block including a cylinder having a cylinder axis, a piston positioned within the cylinder and configured to reciprocate along the cylinder axis, a crankshaft configured to rotate about a crankshaft axis, an air-fuel mixing device configured to provide an air-fuel mixture to the cylinder, a cyclonic air filter positioned entirely below the air-fuel mixing device, and a duct coupling the cyclonic air filter to the air-fuel mixing device and configured to provide air filtered by the cyclonic air filter to the air-fuel mixing device.

Abstract: An internal combustion engine includes an engine block including a cylinder having a cylinder axis, a piston positioned within the cylinder and configured to reciprocate along the cylinder axis, a crankshaft configured to rotate about a crankshaft axis, an air-fuel mixing device configured to provide an air-fuel mixture to the cylinder, a cyclonic air filter positioned entirely below the air-fuel mixing device, and a duct coupling the cyclonic air filter to the air-fuel mixing device and configured to provide air filtered by the cyclonic air filter to the air-fuel mixing device.

Abstract: An engine assembly includes a crankcase, a shaft, a housing, and a cooling fan. The shaft is coupled to the crankcase and defines a rotational axis. The housing has a sidewall that defines an internal space. The cooling fan is disposed at least partially within the internal space and is coupled to the shaft. The cooling fan includes a plate defining an upper surface and a lower surface. The plate is positioned to rotate with the shaft about the rotational axis. The cooling fan also includes a band that has an inner band radius and an outer band radius. The cooling fan also includes a plurality of reversed fins coupled to the band and extending from the upper surface of the plate, further radially outward from the rotational axis than the band.

Abstract: An engine assembly includes a crankcase, a shaft, a housing, and a cooling fan. The shaft is coupled to the crankcase and defines a rotational axis. The housing has a sidewall that defines an internal space. The cooling fan is disposed at least partially within the internal space and is coupled to the shaft. The cooling fan includes a plate defining an upper surface and a lower surface. The plate is positioned to rotate with the shaft about the rotational axis. The cooling fan also includes a band that has an inner band radius and an outer band radius. The cooling fan also includes a plurality of reversed fins coupled to the band and extending from the upper surface of the plate, further radially outward from the rotational axis than the band.