| 摘要 |
PURPOSE: To improve the air intake efficiency by providing a cylinder of an engine by tilting it rearward of a vehicle body, providing an intake port in a front part of a vehicle body of the engine, and arranging the intake port, a carburetor, and an air cleaner on substantially straight line. CONSTITUTION: In an engine 1 mounted on a motorcycle, a cylinder 14 thereof is provided by tilting it at a predetermined angle rearward of a vehicle body for a crank case 16. In a cylinder head 15 in which a combustion chamber 20 is formed, an intake port 21 and an exhaust port 22 are formed on a front side and a rear side of the vehicle body, respectively, and each port 21, 22 is opened and closed by a valve 23 reciprocated by a cam 24. A carburetor 26, a surge tank 27, and an air filter 28 are arranged in the vertically direction substantially linearly to connect them with the intake port 21, and the air filter 28 is fixed on a down tube 3 of a vehicle body frame. Consequently, it is possible to effectively utilize air pressure in air suction and improve the intake efficiency. |
