i am switching pipes

3 replies to this topic
  • lewichris

Posted February 12, 2002 - 10:29 PM


And i need to know if i need to switch jetting. I am new to this so criticisers go easy on me. i am unsure of the jetting that it has currently. the guy that i bought it from put on a megamax tail pipe and rejetted it for that. i dont know what he put in it or how to find out. So my question is i just bought a FMF powercoreIV2 S/A. Do you all think i will need to change my jetting for the new pipe. Any thoughts are welcome as long as you are nice about it. Thanks guys.

  • Terry_in_Reno

Posted February 12, 2002 - 11:19 AM


I have the power bomb and PCIV silencer with YZ timing and have found that the jetting suggested by FMF is very close, even with the 4000-7000 ft elevation I ride.

See my signature for the details it should be a good starting point. You may find you can lower the main one size, but I've not run into the fouling or starting problems with this setup.


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  • MOmilkman

Posted February 12, 2002 - 11:34 AM


Im using practically the same pipe (PCIVSA) and all I did was bump up the main jet to 180.

I left everything else stock except recently I dropped the needle and it seemed like it helped during cold wether starts. (thanks to the T-Talkers here I was helped with that) :)

Other than checking the main jetting I dont know what else to recommend.

  • The_Missile

Posted February 12, 2002 - 10:21 PM


Main jet will need to increase, drop the needle a clip or 2, possibly richen the PJ slightly too.

When I added my FMF header and SX-1 I went from a 150 MJ to a 158MJ and dropped the needle 2-3 clips to compensate. I would probably have richened my pilot circuit from 38 to 40 if it hadnt been slightly too rich from the start.

I'm not suggesting you follow my jetting (unless you go thewhole hog :) ) but the priciple should be the same.


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