| 摘要 |
PURPOSE: To keep ambient temperature around an engine low to enhance the efficiency of charging the engine with intake air by placing a fuel tank on the upper surfaces of right and left main frame members provided to incline outwardly downward, and opening an outside air inlet in a front portion and near the outsides of the members. CONSTITUTION: Right and left main frame members 11 are inclined outward at positions immediately behind a steering pipe 10, and an outside air inlet 25 from which to take in running wind is provided in the outer surface of each inclined part 11a. The running wind allowed into the members 11 flows backward inside the members 11, with a part of the wind guided by a fin 28 and exhausted from an outlet 27 to a space part 35 between the members 11. Since the outlet 27 is located behind a cylinder 20, a sufficient amount of cold running wind flows into the space part 35 surrounded by the members 11 and a fuel tank to keep a carburetor and an air cleaner at low ambient temperatures. Since overheating of the carburetor can be prevented, the temperature of intake air drops, leading to enhanced efficiency for charging an engine with intake air and hence increased engine output. |
