should i re jet

does you carburetor currently have a stock 230 mainjet in it?

ANY TIME you change the incoming or outgoing air, you need to AT LEAST check your jetting. Usually a large flow change will require a matching fuel change.
 
Running a #230 with the lid off on a stock pipe could have been a little lean.

With the DG, start at a #250 with the lid on.

Plug chop to confirm jetting, and proceed from there.