2009 yz450f jetting q's for fmf 4.1 w powerbomb header

2 replies to this topic
  • Sterff884

Posted January 24, 2013 - 08:52 PM


Just curious if anyone has any info on where to start with jetting on a 09 450 with a fmf 4.1 silencer w power bomb header. I ride at 1000ft, Bike is completly stock except for pipe. Need a starting point . Looked on fmf website and they have nothing . Called them and best the guy i could talk to could give me was info for a 04 450f. Also has anyone tried the moto tassinari airforce tuneable stacks and are they worth the money or not ? or are they a bigger pain than what they worth ?

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  • Mark537

Posted January 25, 2013 - 07:07 AM


I got the fmf powerup kit when I got the exhaust. It has different jetting than the original sizes. But I think i am running a 160 main and I think it was a 52 pilot.

  • SparksXR426

Posted January 25, 2013 - 11:28 AM


Unless your bike is running poorly I would just try it stock first, it may not be far off.

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