yz 450 jets

2 replies to this topic
  • GIX1

Posted July 28, 2004 - 05:07 AM


Can everyone or anyone give me some main jet numbers that you have in your bike with a aftermarket exhaust on a 2004 yz 450f just experimenting. Thanks!!

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  • Hank

Posted July 28, 2004 - 06:34 AM


Did they change much on the '04 vs the '03 carb??? I was thinking the only change was that throttle position sensor.... At any rate my '03 at 4000 - 5500 ft elevation (Roughly) I run stock main jet, I beleive 165, with a dual uni air filter. I have a fmf power bomb to fmf t4 titanium 14" pipe. I can tell by the plug I am a little rich... might be from riding when I get a little dirtier than expected air filter.... If I drop the main, to lean, if I drop the needle one clip I loose top end, I run great on a fresh filter, but still pop a little but I get the performance I like. I havent tried changing the pilot jet or air jet yet I am going to get the zip-ty fuel mixture screw today and see what I can get done with that... :thumbsup:

  • GIX1

Posted July 30, 2004 - 04:14 AM


anyone else have a 04 450 ??????? What main jet are you running with aftermarket exhaust???? Anyone

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