To provide a four cycle engine and a motorcycle capable of supporting a chain guide by securing a predetermined thickness between a chain chamber and mounting holes without moving the chain chamber outward.
In the four cycle engine 5 provided with a cylinder block 51, a cylinder head 52 mounted on the cylinder block 51, cam chain 86 transmitting torque of a crank shaft 54 to a cam shaft 81, a chain guide 89 preventing movement of the cam chain 86, and a chain chamber 83 formed in the cylinder block 51 and a cylinder head 52 and storing and retaining the chain guide 89, projection parts 89e1, 89e2 projecting sideward from a side part are formed on the chain guide 89, fitting recess parts 51a1, 51a2 fitting with and supporting the projection parts 89e1, 89e2 are formed in the chain chamber 83, and a run off part 51a11 for avoiding radial interference with mounting holes 51e of the cylinder block 51 on which the cylinder head is mounted in a view from a cylinder axis direction is formed on the fitting recess part 51a1.
NAKAHIRA YASUYUKI
WATANABE KENSUKE
