What is the internal structure of a motorcycle exhaust muffler?

[OCaden]

Motorcycle exhaust pipe internal structure mainly consists of a muffler. Principle of exhaust pipe noise reduction: Motorcycle exhaust pipes primarily use porous sound-absorbing materials to reduce noise. By fixing the sound-absorbing materials to the inner walls of the airflow channel or arranging them in a certain pattern within the pipe, a resistive muffler is formed. When sound waves enter the resistive muffler, part of the sound energy is converted into heat energy through friction in the pores of the porous material, dissipating it and thereby weakening the sound waves passing through the muffler. Principle of noise reduction: Straight pipes do not have internal baffles or similar structures, only external sound-absorbing cotton to block some noise. Exhaust gases are discharged directly without obstruction, causing violent expansion and producing explosive sounds, commonly known as noise. Additionally, due to the longer overlap time of intake and exhaust valves at low RPM, the mixture in the combustion chamber may flow out. The large and open design of straight pipes naturally slows down the exhaust gas flow at low RPM.