An internal combustion engine for being mounted laterally on a saddle-type vehicle includes an AC generator disposed on an end portion of a crankshaft which is supported in a crankcase. An ACG cover covers the AC generator from outside widthwise across the vehicle. The ACG cover includes an electric power transmission line cover bulging portion covering electric power transmission lines extending to the ACG cover and bulging sideways outwardly widthwise across the vehicle. A crank angle sensor is disposed behind the electric power transmission line cover bulging portion in a vehicle front-back direction. The crank angle sensor is thus protected from flying stones, etc. without an increase in the number of parts used and an increase in the weight of the internal combustion engine.

A vehicle includes an engine unit, a radiator, a first passage, and a second passage which is provided below the cylinder head and to which lubricating liquid is supplied. The radiator is arranged in front of the engine unit. The first passage includes a first opening arranged in front of the radiator so as to face the radiator and is configured to guide first traveling wind from the first opening toward the radiator. The second passage includes a second opening arranged outside the first opening in the vehicle width while being partitioned from the first opening, and is configured to guide second traveling wind from the second opening toward the lower supplied member.

In an engine, a cylinder block and a cylinder head are connected with a crankcase in a forwardly inclined posture. A dual clutch connects or disconnects a transmission path of power of the engine to a transmission. An actuator chamber houses an actuator that controls a hydraulic pressure of the dual clutch. The actuator chamber is disposed on an upper surface of the cylinder block at a position posterior to the cylinder head and anterior to the crankcase in a vehicle longitudinal direction.

An internal combustion engine for being mounted laterally on a saddle-type vehicle includes an AC generator disposed on an end portion of a crankshaft which is supported in a crankcase. An ACG cover covers the AC generator from outside widthwise across the vehicle. The ACG cover includes an electric power transmission line cover bulging portion covering electric power transmission lines extending to the ACG cover and bulging sideways outwardly widthwise across the vehicle. A crank angle sensor is disposed behind the electric power transmission line cover bulging portion in a vehicle front-back direction. The crank angle sensor is thus protected from flying stones, etc. without an increase in the number of parts used and an increase in the weight of the internal combustion engine.

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.

The present invention provides a heat dissipation device for an engine of a motorcycle. The device includes a heat dissipation mask. The heat dissipation mask is disposed at a side of the engine such that it is not in substantial contact with the engine. The heat dissipation mask includes an open side that substantially encloses at least one side of the engine. An open is also provided at the bottom of the heat dissipation mask. The heat dissipation mask is configured to substantially correspond to a location of the leg of the rider in a riding position. Some parts of the heat dissipation mask also correspond to the engine so as to prevent the heat from spreading toward the rider. In such a way, a heat dissipation device with a reduced structure is provided, which is easy to install and is capable of dissipating heat around the engine.

A coolant bottle defines a first chamber and a second chamber fluidly coupled to the first chamber at a valve seat. The first chamber is fluidly coupled to a source of heated engine cooling fluid, while the second chamber is fluidly coupled to an engine water pump. A thermally responsive actuator is disposed within the first chamber, and has a thermally actuated sliding member having a valve seat engaging surface. The thermally actuated sliding member is movable from a first open position to a second closed position when the coolant is above a first temperature. The thermally responsive actuator is disposed within the first chamber.

An intake duct has a front-rear two-split structure, and includes a rear duct connected to a body frame and a front duct connected to the rear duct. The rear duct includes a body frame connection portion that is connected to the body frame and is attached with a rear stay that supports a cowl and a meter, and the front duct is directed forward from the rear duct.

An ECU is covered by a fuel tank and an upper cover which are vehicle body trim parts along with the upper surface of an air cleaner box. A frame holding duct is connected to the air cleaner box, the frame holding duct extends vehicle forward from the air cleaner box, is connected to a body frame, and is arranged inside an upper cowl, the upper cowl covering the front portion of the body frame, a branching portion of the intake air is arranged in the frame holding duct, and a branching passage extending from the branching portion is disposed between the upper surface of the air cleaner box and the fuel tank and the upper cover and is positioned in front of the ECU.

There is provided a straddle-type vehicle. A water jacket is configured to cool an engine by cooling water discharged from a water pump. A radiator is arranged in front of the engine. A cooling water stream control unit is configured to control a flow rate of the cooling water to circulate in the radiator, based on a temperature of the cooling water after cooling the engine. The water pump is mounted to a part of a crankcase at one side in a right and left direction of the straddle-type vehicle. The cooling water stream control unit is arranged at a position that is located at the one side of a center of the straddle-type vehicle in the right and left direction, is lower than a cylinder head cover and is located between the engine and the radiator, when seeing the straddle-type vehicle from a side.