Hello all. I am new to the forum I found TT by doing a search on goggle for forums on the xr600, and low and behold I was directed here. I have used the search feature on the site to look up my dilemma, but I am still confused. So here is my problem. I live in the desert after moving from the east coast and started doing longer rides at wot rather then trail riding back east. I noticed on my first few rides that the bike started sputtering in 1st threw 3rd at 1/4 throttle but not to bad (not enough to stop riding.) Anyway it got worse as the months went by. I have cleaned the carb completely twice I have changed the gas in the tank. I have looked for air leaks. I have messed with the main jet, air mixing screw. I have done just about everything that i have read from the forums. Oh it runs liked a raped ape when cold, but as soon as it gets hot, that's when the syptoms occur. I'm at a loss, Is there anything else I could try? Any help would be greatly appreciated.