2008 YZ450f suddenly dies

Brand Yamaha Yamaha YZ450F 2008

4 replies to this topic
  • MotoFixation

Posted October 12, 2015 - 11:50 AM


My 2008 YZ450 starts first kick from cold and ill let it run for 45ish seconds than it dies outta nowhere. I turned up the idle and that did not seem to help. It has very few hours on it like maybe 30 to 50 hours (never rebuilt). Im thinking it may be the fuel screw just have not got around to messing with it much. Any thoughts?

Edited by MOTOFIXATION, October 12, 2015 - 11:50 AM.

  • Krannie McKranface

Posted October 12, 2015 - 02:27 PM


Adjust fuel screw for highest idle

Do valve clearances adjustment

Buy a service manual and start reading up on how to maintain the bike per Yamaha's recommendations

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  • stevethe

Posted October 12, 2015 - 05:02 PM


If your taking it off the choke and its stalling buy a new pilot jet put it in and give it a whirl.

  • grayracer513

Posted October 13, 2015 - 06:59 AM


Try the fuel screw first to see if the pilot jet is in the right range:


Adjustment procedure


Use the fuel screw to check jet size


If it turns out that these checks indicate a too small pilot, you should either try cleaning the jet or replacing it.  A #43 to #45 should be about right.  If you have that size in place already, yours is likely partly clogged. 

  • MotoFixation

Posted October 13, 2015 - 11:44 AM


Thanks guys 

Edited by MOTOFIXATION, October 13, 2015 - 11:45 AM.

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