03 yz450 Wont idle low


3 replies to this topic
  • 777tj

Posted March 19, 2010 - 09:49 PM

#1

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

#2

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:
http://www.thumperfa.../jetting.htm#PJ

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

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Ronus

Posted March 26, 2010 - 06:17 AM

#3

valve clearance will cause idle problem at low idle?

  • grayracer513

Posted March 26, 2010 - 08:21 AM

#4

valve clearance will cause idle problem at low idle?

Yes..





Related Content

Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
Forums
Photo

First Hare scramble tips by dhend8


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies
Forums
Photo
Motocross

Thinking about Yamaha 250... by Arctic Pride


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.