Abstract: A multi-plate friction clutch wherein lubrication sites of the clutch can be efficiently supplied with oil to be sufficiently lubricated. A multi-plate friction clutch includes a clutch outer, a clutch center, clutch plates, and a pressure plate. A center ring protrusion protruding into a cylindrical shape from the outer surface of a center bottom wall part is formed at substantially the same radial position as a plurality of communication holes. Furthermore, a ring recess opened toward the axial center is formed in the inner circumferential surface of the center ring protrusion and the communication holes are so opened as to face the ring recess.

Abstract: A multi-plate friction clutch wherein lubrication sites of the clutch can be efficiently supplied with oil to be sufficiently lubricated. A multi-plate friction clutch includes a clutch outer, a clutch center, clutch plates, and a pressure plate. A center ring protrusion protruding into a cylindrical shape from the outer surface of a center bottom wall part is formed at substantially the same radial position as a plurality of communication holes. Furthermore, a ring recess opened toward the axial center is formed in the inner circumferential surface of the center ring protrusion and the communication holes are so opened as to face the ring recess.

Abstract: In a V-type engine for a motorcycle in which both banks are arranged in a V-shape in a plane orthogonal to the axis of a crankshaft and the heights of both the banks are different from each other, the heights of the pair of banks are visually recognized to be almost equal to enhance the functional beauty of the engine and improve the marketability. A plurality of fins are aligned in the direction along cylinder axes and are provided on sides of cylinders and on sides of dummy covers for covering at least part of cylinder heads from the sides. Wherein the total number and center line mutual distances of the fins are almost equal in both banks. Lengths between the center lines of the fins closest to a crankshaft of the fins and a cross point of the cylinder axes are set to be almost equal in both the banks.

Abstract: In a V-type engine for a motorcycle in which both banks are arranged in a V-shape in a plane orthogonal to the axis of a crankshaft and the heights of both the banks are different from each other, the heights of the pair of banks are visually recognized to be almost equal to enhance the functional beauty of the engine and improve the marketability. A plurality of fins are aligned in the direction along cylinder axes and are provided on sides of cylinders and on sides of dummy covers for covering at least part of cylinder heads from the sides. Wherein the total number and center line mutual distances of the fins are almost equal in both banks. Lengths between the center lines of the fins closest to a crankshaft of the fins and a cross point of the cylinder axes are set to be almost equal in both the banks.

Abstract: To provide an engine cooling system including a water pump for circulating cooling water in order to cool an engine, and a thermostat provided in the water pump in such a manner as to be openable/closable depending on the temperature of cooling water. The thermostat is provided in the water pump with a reduced number of parts, to thereby reduce the cost, weight and the number of assembling steps. A casing of a water pump is composed of a pump body for rotatably supporting a pump shaft and a pump cover connected to the pump body in such a manner as to cover an impeller fixed to the pump shaft. A thermostat is contained in a containing portion formed in the pump cover in such a manner as to be held between the pump body and the pump cover.