1994, smog equipment removed, pod filter (sock type uni), white bros full exhaust (not sure exactly which model), mostly run at 2500' PO says he has a 58 main jet in the bike. Recommended a 50 main jet with a long pilot. I do know the bike stumbles hard in the mid-range and a little in the low range. Backfires and kicks out smoke on downshifting. It can completely die on deceleration. My supermoto also runs just as bad at sea level and smells rich behind me, or so I'm told. Recommendations? A baseline would help as I've never done this before.