2006 YZ450F won't idle properly

6 replies to this topic
  • polarisrmk

Posted June 20, 2011 - 08:21 PM


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?

  • grayracer513

Posted June 20, 2011 - 08:53 PM


It's lean. That could be from a plugged pilot jet, and air leak, or tight intake valves.

  • polarisrmk

Posted June 21, 2011 - 07:35 PM


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?

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  • sawworcs

Posted June 21, 2011 - 07:42 PM


3x for lean. If it has been sitting or had bad fuel through it it is probley the pilot jet. Blocked with varnish or dirt.

  • polarisrmk

Posted June 21, 2011 - 11:08 PM


Just had the carb apart the other day and it was all clean inside, all jets were clear and open, all looked normal

  • grayracer513

Posted June 22, 2011 - 07:17 AM


The difference between a #45 pilot and a #38 pilot is about .0027". A very thin film of varnish will cause at least that sort of reduction in flow WITHOUT blocking the jet completely. It will look good, but it won't work.


  • Mr. Neutron

Posted June 22, 2011 - 10:34 AM


How does your Vacuum Plate (on the slide) and it's seal look? Also, if you had your carb apart (like, say, for cleaning) recently, be certain you got that seal on correctly.....


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