| 摘要 |
PROBLEM TO BE SOLVED: To improve exhaust emission control performance by reducing restrictions in the position and angle of a secondary air passage and facilitating the formation of the secondary air passage, in an engine in which the secondary air passage for guiding secondary air to be mixed in exhaust gas flowing through an exhaust port has the downstream end opened on the exhaust port and is provided on a cylinder head. SOLUTION: At least a downstream side passage part 55b of a secondary air passage 55 is formed on a cylinder head 11, before pressing a valve seat 15 into the cylinder head 11, so that the part of a virtual extension part to the combusting chamber side is overlapped on the valve seat 15 which is pressed in the cylinder head 11.
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