I just bought a roptor 01, the guy that sold it to me have been using a W/B e-series slip-on, but when i bought it he reinstalled the stock pipe.
i just received my brand new W/B e-series, and am gonna install it, my question is, do i need to re-jet ?

 

I dont really think you have to in the beginning but do it at a later time definately

 

you will have to rejet. It will make you run leaner with the pipe. Unless he left the old jets in, but if he did it should have a very black spark plug and run like crap,

Patrick