Abstract: An engine 40 includes a breather device 20 and an oil passage defining member 30 disposed in the breather device 20. The breather device 20 includes a breather main body 22 integral with a crankcase 50, and a breather cover 24. The breather main body 22 and the breather cover 24 define an enclosed space 26 in communication with an inner space of the crankcase 50. The oil passage defining member 30 includes a first member 32 integral with the crankcase 50, and a second member 34. The first and second members 32 and 34 define an oil passage 38. The crankcase 50 includes a transmission chamber 60 in which a main shaft 72 and a drive shaft 74 are disposed, and oil feed holes 82A to 82C through which the oil passage 38 and the transmission chamber 60 are in communication with each other.

Abstract: An engine 40 includes a breather device 20 and an oil passage defining member 30 disposed in the breather device 20. The breather device 20 includes a breather main body 22 integral with a crankcase 50, and a breather cover 24. The breather main body 22 and the breather cover 24 define an enclosed space 26 in communication with an inner space of the crankcase 50. The oil passage defining member 30 includes a first member 32 integral with the crankcase 50, and a second member 34. The first and second members 32 and 34 define an oil passage 38. The crankcase 50 includes a transmission chamber 60 in which a main shaft 72 and a drive shaft 74 are disposed, and oil feed holes 82A to 82C through which the oil passage 38 and the transmission chamber 60 are in communication with each other.

Abstract: A motorcycle includes a cylinder body, a cylinder head disposed above the cylinder body, and a plurality of dowel pins configured to position the cylinder body and the cylinder head. The cylinder body includes a plurality of cylinders and a plurality of bolt insertion holes. The cylinder head includes first and second passages configured to flow oil or air therethrough. The cylinder body includes a first communication port in communication with the first passage and a second communication port in communication with the second passage. The first communication port is disposed in a front left region, and the second communication port is disposed in a rear right region. The plurality of dowel pins consist of a first dowel pin fitted into the first communication port and the first passage and a second dowel pin fitted into the second communication port and the second passage.

Abstract: A motorcycle includes a cylinder body, a cylinder head disposed above the cylinder body, and a plurality of dowel pins configured to position the cylinder body and the cylinder head. The cylinder body includes a plurality of cylinders and a plurality of bolt insertion holes. The cylinder head includes first and second passages configured to flow oil or air therethrough. The cylinder body includes a first communication port in communication with the first passage and a second communication port in communication with the second passage. The first communication port is disposed in a front left region, and the second communication port is disposed in a rear right region. The plurality of dowel pins consist of a first dowel pin fitted into the first communication port and the first passage and a second dowel pin fitted into the second communication port and the second passage.