FMF Powercore IV SA

16 replies to this topic
  • Gadsen

Posted January 04, 2005 - 09:34 PM


OK, give me some input. I just ordered one for my WR450F. Is it going to be too noisy? Does it come with the quiet insert? I've seen this mentioned, but nothing on the website regarding the quiet insert. I was told it will be about 96DB and about 93DB with the quiet insert. Anyone have this and ended up using stock jetting? Do you like it, quiet enough for public lands etc. Thanks! :cry:

  • Moondogger

Posted January 04, 2005 - 11:24 PM


Who told you about the 93db with the quiet insert?

I was thinking about getting the Powercore IV with the insert, but I called FMF directly and talked to a tech person to find out about the noise levels. He said even with the insert the pipe would be above 96db.

Here in CA that's a bad thing, if you get caught by a ranger it's either a ticket or you get sent home. In WA it might be different, but if noise is a concern, I would call FMF directly and talk to one of their techs.

I ended up getting the FMF "Q".

  • Indy_WR450

Posted January 05, 2005 - 12:50 AM


You can get the insert and it quiets the bike down to about the same noise level as a PMB or Baja or GYTR insert on the stock can. You can fine tune it by crushing the end tip which is in the middle of the cannister to fine tune the noise level! I am very happy with this set up. :cry:

  • WR450_in_Turkey

Posted January 05, 2005 - 02:00 AM


I recently fitted the same can to my 03 WR450. It was supplied without the quietcore and was very loud in that state. So noisy in fact you would need to ride with ear defenders on!. The quietcore made all the difference. I have a db meter here if you know what the test parameters are I can simulate the test here next time the bike is out. With regard to the jetting I tried a few changes and ended back where I started at standard. This is an EU model so it is probably not relevant to the leaner US model. MJ 160,PJ 48,PAJ 80,JET needle OBDUQ if its of any use

  • Gadsen

Posted January 05, 2005 - 08:44 AM


...This is an EU model so it is probably not relevant to the leaner US model.... MJ 160,PJ 48,PAJ 80,JET needle OBDUQ if its of any use

Ah, but I imported mine from Canada. Its a Canadian/Australian/New Zealand and ZA model. I odnt know if these are the same as Euro. So I didnt have to deal with lots of stuff like the grey wire, throttle stop etc. I will get the quiet core insert ort do whatver it takes to make it reasonable. Max noise in my state is 96, but I like to keep it at 94 and under. Thanks for the replys. Does anyone have a site for the quiet core insert? I couldnt find it for the Powercore IV SA model on any of the webpages I was looking at. :cry:

  • Indy_WR450

Posted January 05, 2005 - 08:54 AM


FMF web site. No pictures of insert $28.00


  • oldbones

Posted January 05, 2005 - 09:24 AM


My FMF PC IV S/A has consistently tested at 96 or 97db. It's throaty, but not obnoxious. It was bought in 2002 though, and I think the new ones might be slightly different.

  • barefootbob

Posted January 05, 2005 - 09:42 AM


Can't wait utill I can afford a p/iv I like Indys fix for the sound.I take my bikes rite to the ranger's office and get a sound test this way you know your leagle the best part is when the ranger see's you in the parking lot on ride day they remember ya and they wont even bother ya

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  • ncmountainman

Posted January 05, 2005 - 03:38 PM


i was tested with my p/core IV open with the 2" end cap was 102>>> with the quiet core and 2" endcap its 98. i think it was 30" out and 30" behind @ 3,000 rpm but i can't really remember! that was w/out the power bomb header,its said to reduce sound also. and now that its on it does seem quieter but i have not tested since its install. i think if you do like me and get the Q stickers and run the quiet core at sensative areas they will probly leave you alone(once they see the big Q sticker they think your at least tryin'!!) :cry:

  • Divetruck

Posted January 05, 2005 - 06:41 PM


I have a Powercore IV SA on my Aussie 04 WR450. The end cap on the muffler is pop rivetted on, and hence can't have an insert installed. My understanding is that the quietcore only fits into the non SA version of the Powercore IV. This is a different muffler to the SA, as the end cap has socket head screws holding it in place.

  • Gadsen

Posted January 05, 2005 - 06:48 PM


My FMF PC IV S/A has consistently tested at 96 or 97db. It's throaty, but not obnoxious. It was bought in 2002 though, and I think the new ones might be slightly different.

Bones, do you have the quiet insert in it or is this just the Powercore IV SA out of the box? :cry:

  • rickmiester

Posted January 05, 2005 - 07:24 PM


i just bought the white bros e2 for my 2004 wr 450, .its new on the market and the end is tunable it came with the spark arrestor/silencer and another ring about 2-1/2 inch round for race i guess cost 435.00 after tax, the bike runs excellent you should check it out

  • Gadsen

Posted January 05, 2005 - 07:29 PM


FMF web site. No pictures of insert $28.00


Thanks Indy, used the link you posted and its on it way!

  • oldbones

Posted January 05, 2005 - 07:45 PM


Here's a crummy picture. To be honest, I don't know. It was on the bike (new in the showroom) when I bought it in '02. I think they may have changed it since then. I know it was NEVER 100 db as some others have said, so either it's a different design from the new ones, or it's the quiet cap.

I have had it apart to repack, is there some obvious way I would be able to tell?


  • Indy_WR450

Posted January 05, 2005 - 08:37 PM


You have to take the 3 bolts off the rear and pull the cap and spark arrestor off. Then you can see if you have an insert. the insert will be a thin flat plate with a 1" pipe welded to it and protrudes several inches into the exhaust canister. :cry:

  • unkle_george

Posted January 06, 2005 - 12:15 AM


There is a difference between the Powercore IV and the Powercore 4.
The 4 has an endcap that's held on with allen screws and accepts the quite insert.

102+ w/o insert
96 with
~99 Stocker w/o plug

I had to bump my main jet by 2 and move the needle clip, and fuel screw too.

The FMF is much lighter, but maybe only 5-10% more power then stocker with the plug pulled.

- Ryan

  • WR450_in_Turkey

Posted January 06, 2005 - 02:07 AM


Here is a link to a website which has pictures of the quietcore and the SA.



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