| 摘要 |
PURPOSE: To efficiently introduce running wind taken in from an air inlet to a cylinder and to improve cooling performance of an air-cooled engine by forming the air inlet leading running wind between lower extension parts of a fuel tank. CONSTITUTION: Between an air inlet 36 and a cylinder 8, no seam is formed between a cowling 21 and a fuel tank 9 on the circumference wall of an air passage 17, so that the circumference wall of the passage 17 can be formed into an even smooth face. Consequently, during travel, running wind taken inward from the air inlet 36 can be smoothly led to the periphery of the cylinder 8. The passage 17 is expanded in front of the cylinder 8 but throttled in front of the cylinder 8, so that a flow rate of running wind flowing inside the passage 17 is increased toward the cylinder 8 side, and the flowing direction of the wind is forcibly changed so as to be directed toward the cylinder 8 in the flow process. Therefore, the running wind smoothly flows inside the passage 17 without causing any swirl, so that the running wind can be efficiently led to the cylinder 8 to improve, cooling performance of the cylinder 8. |
