A valve mechanism includes a valve, a camshaft, a fixed support, an intermediate swing arm and a supporting base. The fixed support is provided with a connecting-portion via hole running from top to bottom, two oil passages are defined in a connecting portion, and each of the oil passages is connected with the connecting-portion via hole and a corresponding intermediate swing arm shaft hole. The supporting base defines first and second oil feeding passages therein, the first supporting-base oil feeding passage is communicated with the connecting-portion via hole, and an upper end of the second supporting-base oil feeding passage extends to a base-body camshaft supporting portion of the supporting base. An engine and a vehicle are also provided.

A lubricating oil supply structure includes: a shaft; a bearing supporting the shaft and having an oil supply port, through which lubricating oil is supplied to between the shaft and the bearing, and an oil introduction port, through which the lubricating oil is introduced; a first oil passage, connected to the oil supply port, distributing the lubricating oil from an oil pump toward the oil supply port; a second oil passage, connected to the oil introduction port, supplying the lubricating oil introduced through the oil introduction port to a supply destination; a connection oil passage, formed by a gap between the bearing and the shaft, connecting between the first oil passage and the second oil passage, and a throttle portion, formed on a part of the connection oil passage, suppressing a flow of the lubricating oil from the oil supply port toward the oil introduction port.

A gearbox comprising an input shaft fixed with a first gear, an output shaft fixed with a second gear, and a rim gear without a web or hub rotatably mounted on a shaft having a hollow space. A lubrication line extends from within the shaft to a lubrication space disposed between an inner surface of the rim gear and an outer surface of the shaft. The rim gear is held in place on the shaft by a first interior surface of a first chamber member and a second interior surface of a second chamber member.

The cam follower roller device provides a tappet body, a pin mounted into the tappet body, and a roller mounted on the pin and provided with an outer surface and with end faces, axially delimiting the outer surface. At least one lubricant supply through-hole is formed into the thickness of the tappet body and locally faces an edge of the roller delimited between the outer surface and one of the end faces.

Methods and systems are provided for a valve bridge of an internal combustion engine. In one example, a valve bridge comprises a first arm, a longitudinally opposing second arm, and one or more interior walls forming a passage extending laterally through at least a portion of the valve bridge, the passage disposed between the first arm and second arm and forming a first main opening and an opposing, second main opening. A central support structure is disposed within the passage and is formed by the one or more interior walls.

A valve mechanism includes a valve, a camshaft, a fixed support, an intermediate swing arm and a supporting base. The fixed support is provided with a connecting-portion via hole running from top to bottom, two oil passages are defined in a connecting portion, and each of the oil passages is connected with the connecting-portion via hole and a corresponding intermediate swing arm shaft hole. The supporting base defines first and second oil feeding passages therein, the first supporting-base oil feeding passage is communicated with the connecting-portion via hole, and an upper end of the second supporting-base oil feeding passage extends to a base-body camshaft supporting portion of the supporting base. An engine and a vehicle are also provided.

In a valve train of an internal combustion engine, an input sprocket mounting portion is provided on one end of an exhaust camshaft, and a valve operating cam portion is formed on the other end of the camshaft. A decompression shaft of a decompression device is inserted in a decompression shaft hole, which is formed from the input sprocket mounting portion toward the valve operating cam portion. The decompression shaft hole is formed at a position offset from an axis of the camshaft. A camshaft inner oil passage is formed in the camshaft to extend from one end toward the other end of the camshaft in parallel arrangement to the decompression shaft hole to supply lubricant from the bearing journal portion to the bearing journal portion. The above arrangement makes it possible to supply a sufficient amount of lubricant oil to slide portions of the valve train of a saddle riding vehicle.

An internal combustion engine includes: a cylinder head (3); a combustion chamber recess (15) formed in the cylinder head; an intake passage (16) and an exhaust passage (17) formed in the cylinder head and communicating with the combustion chamber recess; a head oil passage (80) formed in the cylinder head, and having a first end (81A) communicating with an oil pump (62) and a second end (81B) opening out at a sliding contact surface of a valve actuating mechanism (23) provided in the cylinder head; and an oil jacket (84) formed in the cylinder head in a path of the head oil passage so as to at least partly surround the exhaust passage.

An engine is provided with a timing chain cover that covers a side where a timing chain is arranged in a spaced apart manner from the side of the engine. An oil jet extending in an output shaft direction is a hollow member including therein an oil passage. One end portion of the oil jet in the output shaft direction is supported in a hole formed in the engine, and the other end portion of the oil jet extends toward the timing chain cover but does not come into contact with the timing chain cover. A pressing part arranged in a spaced apart manner from the timing chain cover in the output shaft direction is located between the other end portion and the timing chain cover in the output shaft direction, and the pressing part is in contact with the other end portion.

An improved, lightweight gear drive having a rim gear mounted on a shaft, the shaft formed of one or more shaft segments, each of the shaft segments supporting a segregated arc. The segregated arcs forming a circumferential portion of a bearing surface of the shaft.