Abstract: An internal combustion engine for reducing the amount of bubbles contained in the circulated oil without reducing the ground clearance of the engine. A crankcase is provided therein with an oil suction passage makes an oil pump and an end part of a bottom wall of an oil sump chamber communicate with each other, passes between the oil sump chamber and a hanger boss, and has a lowest part located below the bottom wall of the oil sump chamber.

Abstract: An internal combustion engine for reducing the amount of bubbles contained in the circulated oil without reducing the ground clearance of the engine. A crankcase is provided therein with an oil suction passage makes an oil pump and an end part of a bottom wall of an oil sump chamber communicate with each other, passes between the oil sump chamber and a hanger boss, and has a lowest part located below the bottom wall of the oil sump chamber.

Abstract: A first muffler (4) is connected to a rear end portion of the exhaust pipe (2) extending from a single-cylinder engine toward one side of a rear portion of the vehicle body and is provided on one side of the vehicle body. A second muffler (5) is provided on the other side of the vehicle body opposite to the first muffler (4) through a connecting pipe (6). An outer side surface near the front end portion of the first muffler (4) and the second muffler (5) are covered with first and second covers (7) and (8) both plated. Each of the exhaust pipe (2) and the first and second mufflers (4) and (5) have double-pipe structure with outside plated. Further, a front end portion of the second cover (8) is curved toward the center of the vehicle body, and a phantom line as a continuous frontward extension from the front end portion of the second cover (8) is positioned before the axis of the connecting pipe (6).