Assessing the Application of the Flexible Joint in the Exhaust Pipe and Braided Wire Damper in Muffler on the Sound Emitted by the CG125 Motorcycle Exhaust

In recent years, noise pollution has become a serious problem for residents in urban areas. Motorcycles have an important role in producing noise..
This study aimed to reduce motorcycle noise by using flexible joint in tailpipe and braided wire dumpers at its exhaust.
In this study, SAE J1287 procedure was used for noise measurement of Amico CG125 motorcycle. Also, for measuring the temperature and pressure of exhausted gas, JIS B 8006 and JIS B 8007 methods were used, respectively. The instruments used for measuring noise, temperature, and pressure of exhausted gas were CEL-6X0 sound level meter, detector of exhaust gas analyzer, Pitot tube, and incline manometer, respectively. Flexible joint and braided wire damper were also prepared (Erteash Gostar Peyman Company)..
By using this new exhaust at speed levels of 1000, 2000, 3000, 4000, and 5000 rpm, we had respectively 3.9, 6.8, 7.4, 5.6, and 5 dBA decreases in total sound level pressure..
Use of flexible joint in the exhaust system leads to conversion of linear vibration to non-linear one, resulting in significant reduction of noise levels..