Abstract: There is provided an installation structure for an oil pressure sensor, including: a crankcase in which a main gallery that extends in one direction is formed; and the oil pressure sensor detachably installed on an outer surface of the crankcase. The oil pressure sensor is configured to detect an oil pressure of a branch passage branching from one end of the main gallery. In a bottom view of a vehicle, a connector of the oil pressure sensor is oriented to an outside of the vehicle, and the connector of the oil pressure sensor overlaps with the crankcase.

Abstract: There is provided a variable valve timing system, including: a camshaft rotatably supported by a support wall of an engine; a variable valve device configured to advance or retard the camshaft by a hydraulic pressure; and an oil control valve. A thrust stopper is formed on an outer peripheral surface of the camshaft. A bearing surface of the support wall is formed with an advance groove through which oil for advancing the camshaft is to pass, a retard groove through which oil for retarding the camshaft is to pass, and an accommodation groove configured to accommodate the thrust stopper. At the bearing surface, the retard groove is positioned on one wall surface side of the support wall, the accommodation groove is positioned on the other wall surface side of the support wall, and the advance groove is positioned between the retard groove and the accommodation groove.

Abstract: There is provided a variable valve timing system including: a variable valve device; an oil control valve configured to control a hydraulic pressure with respect to the variable valve device; an external pipe connecting a main gallery and the oil control valve; and a hydraulic pressure sensor configured to detect a hydraulic pressure in an oil path formed at the crankcase. The oil control valve is disposed on one side surface of the engine in the vehicle width direction. One end portion of the external pipe is connected to one side of the main gallery in the vehicle width direction. In a bottom view of a vehicle, the one end portion of the external pipe overlaps with the crankcase, and the hydraulic pressure sensor overlaps with the crankcase on one side of the one end portion of the external pipe in the vehicle width direction.

Abstract: There is provided a variable valve timing system including: an intake side camshaft and an exhaust side camshaft disposed on a cylinder head; and a variable valve device attached to one end portion of the intake side camshaft. The accommodating wall on an exhaust side of the cylinder head is positioned more inward in a vehicle width direction than the accommodating wall on an intake side of the cylinder head. A first bolt for fixing the intake side of the cylinder head to a cylinder is disposed more inward in the vehicle width direction than the accommodating wall on the intake side. A second bolt for fixing the exhaust side of the cylinder head to the cylinder is disposed more outward in the vehicle width direction than the accommodating wall on the exhaust side.

Abstract: There is provided a variable valve timing system for an engine in which a cam chain chamber is formed in a cylinder and a cylinder head, the variable valve timing system including: a variable valve device configured to change an opening and closing timing of a valve; and an oil control valve configured to control a hydraulic pressure with respect to the variable valve device. The oil control valve is disposed on an outer surface of the cylinder, which is an outer wall of the cam chain chamber. An oil path for hydraulic pressure control enters the outer wall of the cam chain chamber from the oil control valve, extends from a side of the cylinder to a side of the cylinder head, and crosses the cam chain chamber to the variable valve device through an inner wall of the cam chain chamber.

Abstract: There is provided a variable valve timing system for an engine in which a cam chain chamber is formed in a cylinder and a cylinder head, the variable valve timing system including: a variable valve device configured to change an opening and closing timing of a valve; an oil control valve configured to control a hydraulic pressure with respect to the variable valve device. The oil control valve is disposed on an outer surface of the cylinder, which is an outer wall of the cam chain chamber. An oil path enters the outer wall of the cam chain chamber from the oil control valve, and after extending toward a side of the cylinder head from a side of the cylinder, the oil path extends toward the variable valve device through an inner wall of the cam chain chamber through an oil pipe.

Abstract: There is provided a variable valve timing system for an engine in which a cylinder head is fixed on a cylinder, and the cylinder head is suspended on a vehicle body frame, the variable valve timing system including: a variable valve device configured to change an opening and closing timing of a valve according to a hydraulic pressure; and an oil control valve. The vehicle body frame includes a main frame configured to laterally cover a rear side of the cylinder head and a down frame configured to laterally cover a front side of the cylinder head. In a side view of a vehicle, the oil control valve is detachably disposed on an outer surface of the engine below an area surrounded by the main frame, the down frame, and a lower surface of the cylinder head.

Abstract: There is provided a variable valve timing system, including: a camshaft rotatably supported by a support wall of an engine; a variable valve device configured to advance or retard the camshaft by a hydraulic pressure; and an oil control valve. A thrust stopper is formed on an outer peripheral surface of the camshaft. A bearing surface of the support wall is formed with an advance groove through which oil for advancing the camshaft is to pass, a retard groove through which oil for retarding the camshaft is to pass, and an accommodation groove configured to accommodate the thrust stopper. At the bearing surface, the retard groove is positioned on one wall surface side of the support wall, the accommodation groove is positioned on the other wall surface side of the support wall, and the advance groove is positioned between the retard groove and the accommodation groove.

Abstract: There is provided an installation structure for an oil pressure sensor, including: a crankcase in which a main gallery that extends in one direction is formed; and the oil pressure sensor detachably installed on an outer surface of the crankcase. The oil pressure sensor is configured to detect an oil pressure of a branch passage branching from one end of the main gallery. In a bottom view of a vehicle, a connector of the oil pressure sensor is oriented to an outside of the vehicle, and the connector of the oil pressure sensor overlaps with the crankcase.

Abstract: There is provided a variable valve timing system including: a variable valve device; an oil control valve configured to control a hydraulic pressure with respect to the variable valve device; an external pipe connecting a main gallery and the oil control valve; and a hydraulic pressure sensor configured to detect a hydraulic pressure in an oil path formed at the crankcase. The oil control valve is disposed on one side surface of the engine in the vehicle width direction. One end portion of the external pipe is connected to one side of the main gallery in the vehicle width direction. In a bottom view of a vehicle, the one end portion of the external pipe overlaps with the crankcase, and the hydraulic pressure sensor overlaps with the crankcase on one side of the one end portion of the external pipe in the vehicle width direction.

Abstract: There is provided a variable valve timing system for an engine in which a cam chain chamber is formed in a cylinder and a cylinder head, the variable valve timing system including: a variable valve device configured to change an opening and closing timing of a valve; and an oil control valve configured to control a hydraulic pressure with respect to the variable valve device. The oil control valve is disposed on an outer surface of the cylinder, which is an outer wall of the cam chain chamber. An oil path for hydraulic pressure control enters the outer wall of the cam chain chamber from the oil control valve, extends from a side of the cylinder to a side of the cylinder head, and crosses the cam chain chamber to the variable valve device through an inner wall of the cam chain chamber.