WR/FMF Tuning

6 replies to this topic
  • SPDFRK450

Posted January 26, 2005 - 02:49 PM


Ok guys I just put a Powerbomb, and a Powercore4 on my WR426. I love it by the way. However this thing is loud. In the description on Fmfracing.com it says you can tune it to be quieter through the end cap. I didnt see anything in the instructions when I got the pipe about this so any help would be appreciated. Also is there any specific jetting that anybody is running besides stock. If anybody has any experience with this exhaust system some knowledge would be appreciated.

  • Indy_WR450

Posted January 26, 2005 - 03:51 PM


You have to buy the quiet core insert when you order the pipe. Go and check out the FMF web site and you will find it in the accessories for the Powercore 4. I think it is about $30.00 :cry:

  • SPDFRK450

Posted January 26, 2005 - 05:01 PM


Sounds good. Does it affect the power any do you know?

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  • Indy_WR450

Posted January 26, 2005 - 05:08 PM


You loose a little snap off the bottom and it revs slightly slower up top. But is way better than any insert on the stock exhaust! :cry:

  • jonova

Posted February 03, 2005 - 08:44 AM


I have a FMF powerbomb and a factory 4 muffler. I'm running a 170 or 172 (depending on where I ride), the rest is stock except for changing the needle clip down one from stock(richer). I ride at sea level and up into the mountains in mexico. I have the bike uncorked with all the usual mods. I hope this helps.

  • FTD

Posted February 03, 2005 - 02:02 PM


What altitude do you ride at?

  • Gadsen

Posted February 03, 2005 - 06:17 PM


Sounds good. Does it affect the power any do you know?

Dittos to what Indy said. I bought the powercore4 also, then he directed me to the quiet insert. Easy to install, and it makes it sound real nice. Much more "throaty" sounding. I like the sound better and it does quiet it down a good chunk. He also said one could even modify the insert to be even quieter.


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