In the past few months I've raced in Wa, Or, Ca, and this last weekend in Id on my lil F. My bike hadn't missed a beat, but all the tracks were about the same alt. other than Id. I took off to Twin Falls Id. without any jets duhhhhh and when I first started the bike I thought uuuuuhhhhOOOOO. First off it was really hard to start, then it didn't have the snap when rev'd. It died before getting on the track for practice and wouldn't start. kicked my brains out then a friend took over, he got it started and it wouldn't idle. When on the track it wouldn't rev out of corners, it bogged, it didn't want to pull the next gear uphill,just plain ran like hell. I played with the needle and turned the idle way up to get it to idle and got it running the best I could but it was a sad weekend. JET! This is proof these 4 poppers need to be jetted for your area.