| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal combustion engine having a sub chamber function that can eliminate the possibility of the interference with peripheral components at an installation location and that can prevent increases in the number of components and manufacturing man-hours, and a manufacturing method therefor.SOLUTION: In a two-wheeled motor vehicle including an engine 30 discharging exhaust gas from a combustion chamber in a cylinder of a cylinder head 32B via an exhaust port 80, a concave portion 85 is provided in an exhaust channel wall surface 85a halfway along an exhaust channel of the exhaust port 80. It is thereby possible to prevent reductions in a flow volume of the exhaust gas and in a flow velocity thereof, and to reduce exhaust loss. As a result, engine torque can be improved with quite a simple structure. Furthermore, the structure of providing the concave portion 85 in the exhaust port 80 does not impose any restriction on the layout of engine peripheral components. |
