Patent ID: 8695561

Claim:
An engine comprising: a crankcase; a crankshaft accommodated in the crankcase; a connecting rod connected to the crankshaft; a piston connected to a tip end portion of the connecting rod; a piston ring attached to an outer peripheral surface of the piston; a body cylinder connected to the crankcase, and including a cylinder section inside of which the piston is displaced; a head cylinder connected to a tip end portion of the body cylinder; and a cylinder fixing bolt having one end portion extending toward the head cylinder and an other end portion extending toward the crankcase, the cylinder fixing bolt connecting the head cylinder, the body cylinder and the crankcase to one another; wherein the cylinder section includes: a lower section located within the crankcase; and an upper section located at a higher position than a position of the crankcase; wherein the piston ring abuts on the lower section when the piston is located at a bottom dead center; and wherein at least a part of a portion of the lower section of the cylinder section that is located toward the crankshaft as compared with the piston ring when the piston is located at the bottom dead center is thinner than a portion of the lower section that is located on an opposite side to the crankshaft with respect to the piston ring when the piston is located at the bottom dead center.