2006 YZ450F wont idle properly

[2005rmk900]

Hey guys, I've got a 2006 YZ450F anniversary edition, and I’m having a bit of trouble with it, The bike idles good then when you crack the throttle it revs up normally but then wont idle back down properly, but if you give the idle adjust screw a slight turn in either direction it seems to idle back down, anyone have any ideal on what the problem is? The carb has been cleaned already and still no change, I also ran the bike with the air box off, and noticed that the slide in the carb was fluttering up and down slightly, is this normal? Could this be part of my trouble?

 

[suzuki_ryder]

Your idle is still too high if it hangs up. Turn counter clockwise until it stops hanging up. The slide chatter is normal also.

 

[goodngrubby]

sounds like valve adjustment.

 

[TheMuffinMan]

Check that you carb boots are fully seated and that the clamps are tight. Check the fuel screw on the bottom of the carb. First of all, is it there (vibration and improper adjustment can make them fall out)? If it is there pull it out carefully and check that the spring, washer and o-ring are there and in that order: they are very tiny and easy to loose while doing a carb cleaning. If they do not come out with the screw check to make sure they didn't stick in the carb. Then put them back on the screw and thread it into the carb until the screw is fully closed, then turn it back out 2 1/2 turns. Now start the bike and get it up to operating temp (when the rads are hot to the touch) now if the idle hang is still there, turn the screw out in 1/4 turn increments and see if the condition persists (this will affect the idle as well so you will have to play with it at the same time). If you go more than 1 1/2 turns out and it still isnt right you will need to go up one size on the pilot jet and start over. If the adjustments have absolutely no effect then your valve clearances are likely out of spec and will need adjustment.