Hey all, new here and I just picked up my first ATV. Its a 2004 400EX that ran good when I bought it and good when I took it out for the maiden voyage. The only issue it had when I was riding it through the trails is it wouldn’t idle at all, kept just dying on me whenever we would stop, a little throttle and it was fine so I assumed I needed to clean the carb and get some new gas.

Pulled the carb apart and soaked it in the gallon carb cleaner and she came out nicely. It had a 175 main jet but only running a UNI filter, so I installed a 152 jet and a new 42 slow jet hoping to make it idle better incase the old jets didn’t come clean.

Put it back together and no start at all. It fired for a second with the choke fully on but I had to give it tons of throttle to keep it going. Took the carb off and checked it over and its all good.

Pulled the plug and it was fouled black, likely from to big of a jet, so new plug in and I have good spark but still won’t run.

Checked and reset the valve clearances and still no fire. Pulled the valve cover off and it looked the cam was a tooth off. Pulled the tensioner out, reset the cam so it lined up right and put it back together. Again, no fire.

I’m pretty lost as to what to do now. Any suggestions? I really wanted to ride this weekend but its looking like that isn’t going to happen now.

Thanks