What elevation is your bike jetted for now? Will the trails be tight and technical or will you be on the main jet?
FWIW, when I go from my normal 4,000 - 6,000' jetting up to 8,000'+ on my bikes it has always worked well to move the needle clip up one groove and to turn out the airscrew. The higher elevation stuff I ride you just don't get on the main jet at all.
im under 1500 hundred feet right now, i called a shop in carson city and asked them, i went 3 sizes down on the main(im going to be doing a lot of wfos)and 2 sizes down on the pilot, and ill see how that works this weekend
hey i have a 95 yz 250 with pro circuit exhaust too and i re-jetted it for 5-8 thousand feet i wish i remembered the size jets i used then i would tell you but i think i went down like 3 sizes on the pilot and 2 on the main and it rips it works way better when jetted properly i highly recamend it. heres a pic of mine but sadly i have to sell it because i now have a 03 cr250 which rips even more
yamarider: i bought two mains today anyway, 2 sizes down and 3 sizes down, along with a 2 size down pilot, depending on how it runs the first day up there, i might put in the bigger main of the 2 i purchased, thanks for the info, and i hope you eventually come back to the blue side
p.s. where did you get those plastics on your yamaha?