I have two wolverine's, a 2000 with 120 hrs on it and a 2001 with 40 hrs on it. they both have k&n air filters on them. the 2000, I drilled 1 inch holes in the air box lid and can tell it runs a little stronger than the other, but it doesn't start as good. in warm weather, the one with the holes in the air box has to be choked, the stock air box does not need choked. does this indicate the machine with the extra air needs a larger jet? if so, is this a big job? is it just the main jet that you change?

 

It does sound a little lean,the best way to jet it is to buy a dynojet jetting kit.It comes with an altitude chart for perfect results the first time.You will notice an increase in horsepower and easier starting.
Bearman