I have been working on my 2005 WR450 way longer into the riding season than I would like to. I have a problem with the bike running without the choke on. I have totally rebuilt the top end, to include valve adjustment and new rings. The bike will just not run without the choke on. I have fiddle-farted with the Air/Fuel and Idle adjustments so much I fear that I will wear out the threads!! When I do ride the bike with the full choke on, it has extremely choppy throttle response. I turn off the choke and it cuts out. It appears the vacuum lines are correct. It starts, so I know I have spark. I have cleaned the carb so many times I feel like I am the Bo and Luke Duke of the 450 world. There has go to be an answer, but I'm at a loss.