| 摘要 |
PROBLEM TO BE SOLVED: To provide a decompression mechanism for 2-cycle engine which is reduced in a load applied to a starter motor at engine starting, reduced in a required force for pulling of a manual recoil starter, and formed at a low cost without processing an inner peripheral wall surface of a cylinder bore and an exhaust valve itself. SOLUTION: In this decompression mechanism for 2-cycle engine, the exhaust valve 19 which opens/closes an upper edge in an opening at the inner peripheral wall surface side of an exhaust passage 13 to change an exhaust timing is arranged to a cylinder 8 in which the exhaust passage 13 is formed to be opened to the inner peripheral wall surface 11a of the cylinder bore 11. In the decompression mechanism for 2-cycle engine, a decompression hole 25 for reducing a secondary pressure force at the engine starting is formed between the inner peripheral wall surface facing to a combustion chamber of the cylinder bore 11 and the exhaust passage 13 such that the decompression hole 25 intersects a moving path of the exhaust valve 19 in a communicating manner, and a decompression hole opening/closing part 24 for opening/closing the decompression hole 25 is provided to the exhaust valve 19.
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