03 yz450 Wont idle low

3 replies to this topic
  • 777tj

Posted March 19, 2010 - 09:49 PM


my 03 yz450 is backfiring under decel... and whenever i get the idle semi dialed, when i give it gas it kicks to a high idle and wont idle low again. any ideas

  • grayracer513

Posted March 20, 2010 - 07:42 AM


That is a "hanging" idle. Caused by a lean condition. Backfiring under decel is also either a leaky exhaust or a lean idle. Try dialing in the pilot screw first:

If that doesn't work, check for external vacuum leaks around the intake manifold, and check your valve clearance.

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  • Ronus

Posted March 26, 2010 - 06:17 AM


valve clearance will cause idle problem at low idle?

  • grayracer513

Posted March 26, 2010 - 08:21 AM


valve clearance will cause idle problem at low idle?


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