RE: YS 120 Muffler
will do.. I haven't been too happy with Pitts mufflers on 4-strokes, so I think one of their bullets might work just fine.
One other quick question before I get my drill out and ruin something.. I've seen other posts where you're recommended drilling a 1/8 hole in the throttle inlet to assist with idle smoothness... does this hole go in the large side of the throttle butterfly? I just want to confirm first.