jetting has always thrown me for a loop....that's what everyone says...."jet bigger the closer you get to sea level" but both of my bikes are backwards....at sea level, on my '99, I run a 310 at 4500 ft elevation i run a 340....on my 421 I used a 160 for the break in proocess and I use a 155 at 4500ft elevation.... I can't remember what i was running at 200ft above sea level..i want to say I ran a 148..but it's been too long.
I've also heard people say that since the air is thinner the higher you go, the bigger your main has to be to compensate for the thinner air....
I jet according to what my bikes tell me....