The application relates to a motorcycle and a
muffler thereof, a catalyst deterioration identification method and a storage medium. The
muffler of the motorcycle comprises a
muffler body, a first catalyst, a front
oxygen sensor and a rear
oxygen sensor. An air inlet of the muffler body is provided with a pipeline for communicating with an exhaust port of an engine. The first catalyst is arranged on the pipeline. The front
oxygen sensor is located upstream of the first catalyst. The rear
oxygen sensor is located downstream of the first catalyst. The interval between the central axis of the front
oxygen sensor and the central axis of the rear
oxygen sensor is S, S is 350mm-480mm; the volume of the first catalyst is B, the displacement of the engine is V, and the volume of the pipeline region corresponding to the central axis of the front oxygen sensor and the central axis of the rear oxygen sensor is C, B is 0.8V-1.4V, and C is 1.1V-2.1V. If the first catalyst does not deteriorate, the rear oxygen
electric signal curve is a straight line or substantially a straight line, that is, the rear oxygen
electric signal has a small number of flip times. Therefore, the identifiable degree can be improved, and the judgment accuracy is high.