Jetting Qs

244 replies to this topic
  • Dez613

Posted January 31, 2004 - 07:01 PM

This may sound stupid, but are you sure you are not just hitting your rev limiter on the top end? I went from a WR250 to 04 WR450 and thought "CRAP! why is this cutting on top", and then DUH! I was used to reving my 250 to the moon and was riding the 450 same way. :)

  • Dez613

Posted January 31, 2004 - 07:02 PM

Also a buddy told me today to drop a stock YZ needle in it and it makes a huge difference. I haven't tried it yet, but intend to next week :)

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  • woodsk

Posted February 16, 2004 - 06:59 PM

I bought my '00 WR400 with the FMF Q, and powerbomb header already installed. If I switched back to the stock silencer (came with the bike) would I need to looking into adjusting the jetting. This would be entering new terriority for me but I gotta learn sometime.


  • Dez613

Posted February 16, 2004 - 07:49 PM

I went from a stock uncorked pipe, no airbox lid, uni filter to an FMFQ and powerbomb and didn't change the jetting at all, worked great, should work cool in reverse.
BTW this was on my 01 WR426 , also if you switch back to the stock silencer, but not the stock headpipe you will need the FMF sleeve that adapts the different size from headpipe to mid pipe.

  • PumpkinJockey

Posted April 27, 2004 - 04:29 PM

I have an 03 ktm 450 exc with jd's jetting kit. I live around Baton Rouge,LA. No altitude, High temp, & High humidity. Runs good set up by directions stock w/red needle.

I changed the muffler to a T-4. It was too loud and ran lean. I made a baffle insert for the T-4 and got the sound to 96db. It runs ok but still a little lean. Should I try the blue needle, move the red or change jets?

:usa:Thanks, DARYL


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