FMF exaust adjust

6 replies to this topic
  • windseeker1

Posted November 30, 2005 - 04:22 AM


I got me a brand new FMF powercore IV exaust for my wr426f and i installed it on the bike about 3 weeks, but now i wonder if i need to adjust something in the bike like jetting or throttle, the bike seems to run fine!

Can i damage the bike if i let it stock in the adjustments? :applause:


  • Indy_WR450

Posted November 30, 2005 - 04:51 AM


You should not be able to damage your bike. The FMF Powercore 4 should require rejetting. But if it runs fine you are good to go! :applause:

  • windseeker1

Posted November 30, 2005 - 05:44 AM


How can i see if the bike needs to be rejetted?

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  • windseeker1

Posted November 30, 2005 - 09:31 AM



  • dbailey223

Posted November 30, 2005 - 10:04 AM


I believe that the big signs are if you gets pops or backfires on deceleration, hesitations, bogs, etc.

  • Anthony CRF450

Posted November 30, 2005 - 02:41 PM


i installed a factory 4 to my wr450 05 and needed to jet and lift the needle to the top clip. it runs like a dream now! i recently installed a FMF quiet insert and it is great- More power and sounds great too :applause:

  • windseeker1

Posted December 02, 2005 - 08:59 AM


Thank u for the inputs!


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