I had a problem with the way my yz400f was running so first I will tell you what it was doing. First off it wouldnt idle without the choke on no matter what I did to the idle adjustment but it would run with the choke off if I kept on the throttle pretty heavily but it was popping like a popcorn machine so I killed the engine took it back to my garage pulled the carb and cleaned it out then I reinstalled the carb and when I go to start the bike I can kick it over without using the compression release and that was never possible. So my first thought was that there was something wrong with the compression release valve but it seems to be working fine. Does anyone know what would be causing this? If its something wierd you will have to explain it to me im not a 4-stroke mechanic. Thanks alot.