I just bought a 2003 WR 450. When I was at the guys house riding it, it ran fine with no problems, but ever since I transported home in my truck which was about a 3 hour drive, it started to run like crap. When I have the choke pulled out, it runs like a dream, very steady idle, no problems at all. If it take the choke off, it has a very unstable Idle, i have to crank up the idle speed so it will stay running but after running it for a while once the bike gets nice and hot it idles higher, but still not very steady. This leads me to think that it is the carb, i have cleaned it once but maybe I missed something. i have had friends tell me it might be a plugged pilot jet but I just want to get some other opinions. I also plan on changing the spark plug.