what do you mean sir? the return exhaust from pipe to the air filter?
if I'm right then the answer is yes but you need to close the hose going to the air filter... but there is a bit of performace effect base on my personal experience, when I installed my Powerpipe w/o that return exhaust. It feels like the pipe is not tuned on the carbuerator, it's sound like the engine is lacking of air if I'm not mistaking? just correct me if I am wrong all of the Masters here in YT135