Power unit

A power unit comprising:

• a crankcase which accommodates a crankshaft and a main shaft arranged in parallel to each other;
• a crank side cover which covers one end portion of the crankshaft from the outside in an axial direction of the crankshaft;
• a primary driven gear which is provided in the main shaft and meshes with a primary drive gear of the crankshaft;
• a clutch provided at one end portion of the main shaft;
• and
• a clutch cover which covers the clutch from the outside in an axial direction of the main shaft and is fastened and fixed to a packing surface provided on the crankcase to surround the clutch,
• wherein the primary driven gear and the packing surface overlap on a virtual straight line obtained by connecting a center of the crankshaft to a center of the main shaft when viewed from the axial direction of the main shaft, further comprising:
• a valve operation mechanism member provided on the crankshaft,
• wherein a wall body which protrudes further outward in the axial direction of the crankshaft than the packing surface and surrounds the valve operation mechanism member is provided on the crankcase, and
• a relief portion which relieves the clutch cover is formed in a portion of the wall body adjacent to the clutch cover, wherein
• a relief portion formation surface of the wall body extends obliquely with respect to a central axis of the main shaft.