I have a 96 Scrambler 400 2 stroke. It was running fine and then last spring took it for a short ride and it stalled out and has not been running right ever since. I've checked out spark, fuel, etc. It starts up and runs fine until you take it out, warm it up, and give it full throttle. It then loses power, chokes and stalls out. Doesn't start again until next day when it has cooled down. I took the air cleaner off and noticed that when running there is some blowback from the carb. Is that normal? I was thinking that I probably need to take the reed valves out and replace them. I just wanted to get some input from some of you before I pull the carb off and take the valves apart? Thanks.