exhaust question

[overbore]

If a exhaust is shorter and the same size will it allow more air making the bike run better and leaner?same thing for if its bigger around wil it allow more air?I guess I am trying to understand for jetting if I ever changed and see if it really helps.Thanks

 

[EricGorr]

Ok you pretty much lost me there. Maybe its just early and I'm thinking about that turkey cooking in the oven.