i have a bore kit on my tomos which up until recently has been running fine. The bike started to pop and sputter at high speed, which has happened before, do to the biturbo leaking. I found that there was a large break in the meatl right where the center bracket holds it onto the moped. I was able to seal up the hole by welding it. However, this did nto full fix the problem. I am almost posotive that it is not leaking any where, because i just put a new gasket in, and sealled the hole, and yet it still sputers very little at high speeds. Is it possible that i somehow changed the internal dimensions or something that would be causing this? i would appreciate some help on the subject, because i may end up buying a new pipe, if i cant get it to stop sputtering.