| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motorcycle capable of sufficiently drawing out engine output performance and capable of sufficiently reducing high-frequency components of exhaust noise. Ž<P>SOLUTION: An exhaust pipe 40, into which exhaust gas from an engine having a single cylinder flows, is provided with a three-way catalyst 90. The exhaust pipe 40 includes a first pipe 42 inserted into a muffler 30 and a second pipe 44 extending toward a downstream side from the first pipe 42 within the muffler 30. A narrowed part 47 having an inner diameter smaller than that of a cylindrical part 46 of the first pipe 42 is provided in a downstream-end opening of the first pipe 42. The narrowed part 47 is inserted into an upstream-end opening of the second pipe 44. A first expansion chamber 70 that integrally encloses the outer periphery and the downstream-end opening of the second pipe 44 is formed within the muffler 30. A plurality of holes 45 are formed in a distributed manner in a region, except a downstream region the second pipe 44, of a peripheral surface of the second pipe 44. The length in the axial direction of the downstream region is not less than 1/3 times the inner diameter of the second pipe 44. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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