Patent ID: 7900442

Claim:
An engine comprising: a cylinder head having an exhaust gas passage, a lower end, an outer peripheral surface, an air entrance on the outer peripheral surface, and a matching surface disposed at the lower end of the cylinder head between the cylinder head and a cylinder body; and a secondary air supply apparatus for supplying secondary air into the exhaust gas passage in the cylinder head, the secondary air supply apparatus including a secondary air passage, the secondary air passage including a first passage portion, a second passage portion, a third passage portion and a fourth passage portion, the first passage portion linearly extending from the air entrance on the outer peripheral surface of the cylinder head to the matching surface at the lower end of the cylinder head, the second passage portion comprising a groove extending along the matching surface, and extending from a downstream end of the first passage portion to a region below the exhaust gas passage, the third passage portion extending upwardly from a downstream end of the second passage portion, and the fourth passage portion extending from a downstream end of the third passage portion to the exhaust gas passage.