What i would do first is start by doing the easiest thing first, start by rasing the idle( when looking into the carb from the airfilter intake the gap at neutral should be 1-2mm. Another thing you can do if this is the same problem i had lean the low speed needle and high speed needle a 1/4 turn. After this dont do any adjustments over a 1/8 of a turn. It could be to rich becuase of your alttitude. Some more people might be able to give some more sujestions. But always start with the easiest things first. If this doesnt help come back and ask.