With the implementation of environmental protection regulations, the four stroke engine has gradually replaced the two stroke engine. With the opening of imported vehicles, more and more motorcycle refitted parts have emerged in the market. Among them, the exhaust pipe is one of the most frequently modified items.

The exhaust pipe is divided into back pressure pipe, straight pipe and diffusion pipe. From the tail section of the exhaust pipe, in order to maintain the overall back pressure resistance, the back pressure pipe is equipped with several cross diaphragms inside the pipe body. This design can also reduce the noise. After considering the environmental protection regulations, the original factory vehicles mostly adopt the back pressure pipe design; In order to reduce the exhaust resistance, the bulkhead inside the pressure return pipe is removed from the straight pipe, so that the exhaust gas can be discharged more smoothly and quickly. However, the noise produced by the straight pipe design is often criticized.

Diffuser is more special in structure than the first two models, and has no obvious outlet design. Instead, it uses the gap between the diffuser at the end to exhaust the waste gas. At the same time, the back pressure resistance of the exhaust pipe can be adjusted by changing the number of diffuser.