2001 yz 426 idle issue

3 replies to this topic
  • guccimanescarwash

Posted May 28, 2015 - 09:15 AM


when I get my bike warmed up it will idle very high unless I turn down the idle a bunch and then it will just die instantly, but if I leave it idling high it will come back down to a perfect idle but as soon as I touch the throttle it will idle high aging then eventually come back down. I just rebuilt the carb all new jets and other things and the bike runs great all of the time. the plug is a little rich but nothing to be worried about. Any ideas are welcome,  but I think that the wheels on the carb slider are worn out and there is some play,

  • guccimanescarwash

Posted May 28, 2015 - 09:20 AM


Also the choke does not leak and I have sprayed the carb down with cleaner and it stayed idling the same, the valves are adjusted right, if I pull the hot start out and push it in fast it will make it idle fine but as soon as I touch the throttle it will idle high again. 

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  • grayracer513

Posted May 28, 2015 - 09:34 AM


That is a condition called a "hanging idle", and it's caused by a lean condition, not a rich one.  The plug is black because it hasn't gotten hot enough to burn off the slop in a while.


The lean idle is caused by one of the follwing, most of the time:

Check the pilot screw adjustment, check for air leaks, check your valve clearance, then pull the carb to clean and inspect the pilot jet.

  • guccimanescarwash

Posted May 28, 2015 - 11:00 AM


I just rebuilt the carb new jets and pilots and set everything back to the stock setting, and I know the valve clearances are good I just cheeked them not to long ago and I do not ride very much. but is the slide is loose due to the wheels being worn out wouldn't that cause air to get through around it when it moves but seal when it has been their for a minutes, also could it be because the cam chain is stretched out because of how old it is and set it off one tooth. 

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