I just moved from the east coast (sea level) to the mountains in colorado. so i took my honda in to get it jetted, they did it. Then when i got home i fired it up and started goin up and down my street to see how it ran, it was sputtering alot, a couple times it almost died, and it was backfiring when i was slowing down. I let it run in my garage for a bit, and the idle seemed to calm down and become steady, but it still backfires more then normal when i rev up the rpms. What did they do to my wheeler that would make it do that now. I rode it a couple times before getting it jetted and i didnt have much of a prob it backfired a little but not bad, only when it got real hot.

 

Backfire is a symptom of lean...which Im sure they leaned things a bit for Colorado. At most, they should have dropped it one size on the main jet, and turned the mixture screw in 1/4 turn.
Id count the number of turns, the mixture screw takes, to bottom out. Do this lightly, the mixture screw can deform if you force it. Write down this number of turns, because if want to return the setting to where it was, you can. Then I would start by going out 1/4 to 1/2 turn more than they had it, and see how it runs.

 

just to be clear, what do you mean by bottoming out, and should i turn it clock or counter clock to get there?