OVERHEAD VALVE TYPE FOUR-CYCLE ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an overhead valve type four-cycle engine where a breather passage is situated such that an engine is prevented from increasing in size and an oil return passage is prevented from being lengthened. SOLUTION: Push rods 16 and 17 to drive suction and exhaust valves 14 and 15 situated above a cylinder 6 is situated at the side of a cylinder 6. A breather passage 28 to intercommunicate a crank chamber 27 and a rocker arm chamber 31 is provided with a first passage part 28A passing through the flywheel 9 side and the side on the push rods 16 and 17 side in the cylinder 6, and a second passage part 28B extending from the push rods 16 and 17 side to the antipush rod side in a cylinder head 6. A check valve 34 for the breather passage 28 is situated at a connection part between the first passage part 28A and the second passage part 28B. COPYRIGHT: (C)2003,JPO