| 摘要 |
A first head section is arranged between a first cylinder side wall and a second head section in the axial direction of a cam shaft. The second head section is arranged between a second cylinder side wall and the first head section in the axial direction of the cam shaft. The distance between the first cylinder side wall and the first head section in the axial direction of the cam shaft is shorter than the distance between the second cylinder side wall and the second head section in the axial direction of the cam shaft. The distance to the first head section in a cylinder axial direction from a third virtual plane, which includes the axis of a crank shaft and is perpendicular to a cylinder axis, is shorter than the distance to the second head section in the cylinder axial direction from the third virtual plane. |
