A compression release mechanism including a camshaft, a cam provided on the camshaft and protruding outward in a radial direction of the camshaft, a lever, of which a portion is disposed in the camshaft, a support shaft supporting the lever such that the lever is swingable between a first position and a second position relative to the camshaft, and a spring attached to the camshaft, to urge the lever toward the first position. The lever includes a cam portion configured to protrude out from the camshaft with the lever at the first position, a centrifugal weight for moving the lever toward the second position in accordance with rotation of the camshaft, and an abutment portion configured to be in abutment with an inner peripheral surface of the camshaft with the lever at the first position, and be located away from the inner peripheral surface with the lever at the second position.

A type III rocker arm assembly operable in a first mode and a second mode based on rotation of a cam shaft includes a rocker shaft and a first rocker arm assembly. The first rocker arm assembly receives the rocker shaft and is configured to rotate around the rocker shaft in the first mode based on engagement with the first cam lobe. The first rocker arm assembly collectively comprises a valve side rocker arm, a cam side rocker arm and a latch pin. The valve side rocker arm defines a valve side rocker arm bore. The cam side rocker arm defines a cam side rocker arm bore. The latch pin assembly is received by the valve and cam side rocker arm bores and selectively couples the valve side rocker arm and the cam side rocker arm for concurrent movement in the first mode.

An internal combustion includes: a camshaft having a metal core rod insert formed centrally in the camshaft and a driven gear, an exhaust cam, etc. formed of resin integrally with the camshaft; and a decompression mechanism. The decompression mechanism includes: a pair of supporting protrusions provided on the driven gear and each having an insertion hole; a decompression member having a pair of projections disposed between the supporting protrusions; and a biasing spring disposed between the projections for normally biasing the decompression member toward the exhaust cam. The camshaft also has a guide recess and a balancing recess formed in opposite sides of the camshaft, and the metal core rod is exposed through the guide recess and the balancing recess.

A camshaft has a decompression device for an internal combustion engine, wherein a valve lifter is rotatably supported in a base circle of a cam, which can be brought into operative connection with a gas exchange valve via rotation. The valve lifter is operatively connected to a centrifugal fly weight, which is arranged coaxially to the camshaft and which is rotatably supported, in such a way that the valve lifter forms a contour of the base circle in the region of action with the gas exchange valve from a certain rotational speed of the camshaft. The camshaft has a cavity in the region of the centrifugal fly weight, to which cavity lubricant pressure can be applied. A radial first bore from the cavity to the centrifugal fly weight is arranged in the camshaft. A slideable element that can be displaced by the lubricant pressure is arranged in the first bore. By way of the design of the camshaft, an unstable centrifugal fly weight is stabilized and thus acoustics are improved.

A two-wheeled vehicle is provided including a frame, front and rear ground-engaging members each supporting the frame, a straddle-type seat, a handlebar for steering the vehicle, at least one light device configured to operate in a hazard mode, an engine supported by the frame and operably coupled to the ground-engaging members, a tilt sensor, and a vehicle control unit in communication with the tilt sensor. The vehicle control unit is operative to detect a tilt angle of the vehicle based on output from the tilt sensor. The vehicle control unit is operative to determine a tip-over condition of the vehicle based on the detected tilt angle exceeding a threshold tilt angle. The vehicle control unit activates the hazard mode of the at least one light in response to the determination of the tip-over condition.

A type III rocker arm assembly operable in a first mode and a second mode based on rotation of a cam shaft includes a rocker shaft and a first rocker arm assembly. The first rocker arm assembly receives the rocker shaft and is configured to rotate around the rocker shaft in the first mode based on engagement with the first cam lobe. The first rocker arm assembly collectively comprises a valve side rocker arm, a cam side rocker arm and a latch pin. The valve side rocker arm defines a valve side rocker arm bore. The cam side rocker arm defines a cam side rocker arm bore. The latch pin assembly is received by the valve and cam side rocker arm bores and selectively couples the valve side rocker arm and the cam side rocker arm for concurrent movement in the first mode.

A decompression shaft (56) of a decompression device (50) includes an engagement pin (53) that is guided by a guide groove (51a) formed in a decompression weight (51), a decompression cam (54) that is provided on one cam surface of an intake valve cam (25c) and an exhaust valve cam (25b) so as to advance and retreat, and a connection portion (55) that connects the engagement pin (53) and the decompression cam (54). The decompression weight (51) is formed with a rotation restricting groove (51e) that restricts rotation of the decompression shaft (56) when a force acts in a direction in which the decompression cam (54) moves on the decompression shaft (56) from an advanced position to a retracted position when an engine (E) is stopped and that is continuous with the guide groove (51a).

A compression release mechanism including a camshaft, a cam provided on the camshaft and protruding outward in a radial direction of the camshaft, a lever, of which a portion is disposed in the camshaft, a support shaft supporting the lever such that the lever is swingable between a first position and a second position relative to the camshaft, and a spring attached to the camshaft, to urge the lever toward the first position. The lever includes a cam portion configured to protrude out from the camshaft with the lever at the first position, a centrifugal weight for moving the lever toward the second position in accordance with rotation of the camshaft, and an abutment portion configured to be in abutment with an inner peripheral surface of the camshaft with the lever at the first position, and be located away from the inner peripheral surface with the lever at the second position.

A decompression shaft (56) of a decompression device (50) includes an engagement pin (53) that is guided by a guide groove (51a) formed in a decompression weight (51), a decompression cam (54) that is provided on one cam surface of an intake valve cam (25c) and an exhaust valve cam (25b) so as to advance and retreat, and a connection portion (55) that connects the engagement pin (53) and the decompression cam (54). The decompression weight (51) is formed with a rotation restricting groove (51e) that restricts rotation of the decompression shaft (56) when a force acts in a direction in which the decompression cam (54) moves on the decompression shaft (56) from an advanced position to a retracted position when an engine (E) is stopped and that is continuous with the guide groove (51a).

Systems, apparatuses and methods are disclosed that include an internal combustion engine including a plurality of cylinders operable by a valve actuation mechanism including a lifting mechanism having a compression brake valve profile configured to selectively lift the exhaust valves on a downstroke of the cylinders in response to a cranking condition of the internal combustion engine, wherein the compression braking valve profile is phased to the upstroke of the pistons.