Ive been messing with the q4 for weeks trying to make it as quiet as stock without performance loss.. I got the db dawg, tried different angle aft pipes angling down, repacking, etc. I ordered a "quiet core" and was going to hack it to fit backwards and bolt it on for an angle down aft pipe and shove the db dawg in.. etc.. this is what happened: The Q4/power core 4 quiet insert is DIFFERENT than the stock Q4 spark arrestor insert.. the orifice is smaller.. about the same dia as the db dawg, but much larger than klx kawi stock. I put it in right out of the box.. started bike up.. and it was almost as quiet as the stock kawi!! Took it out for a speed test.. normally with the q4 I can go 85 indicated sitting straight up with as much wind resistance as poss.. with the quiet insert I just did 87 indicated.. no perform hit at all.. and QUIET!!! Unbeleivable.. Im done tinkering and will post pics below.. in the first pic the quiet core insert is in the Q4, stock Q4 insert held to the right, db dawg up on the seat with stock Kawi pea shooter. I ordered the part from WRP Woods Rider Parts.com (FMF Titanium Power Core/Power Core 4/Q4 Quiet Core Insert

The quiet core comes with a spark arrestor which has to be snipped a little and an extra baffle attached and is just a hair louder than stock Kawi pea shooter.

 

What is the physical difference between the q4 insert and the quiet core insert? Is it a mesh-type arrestor? Thanks.

 

stock q4 arrestor is mesh, and wider diameter hole
quiet insert is mesh, a baffle, and narrow hole (1 1/8 in)

 

Good to know...I have the Q4 on my klx4 and was looking to quiet it down for some places i ride.(It's pretty quiet already) And need a new muffler for the klx331...that BG muffler is insanely loud! I'm always about to ditch the whole bike after a 6 hour enduro because of the headache it gives me.

 

I don't get it, your muffler body is the FMF Q4, and you added the quiet core insert that FMF sells for the Q4 muffler and it made it quieter. right?

I am very happy that something is as quiet as stock without being as restrictive and heavy as the stock muffler. Great news!

 

Highbeam thats exactly right.. quiet insert sold seperately for Quiet core/Q4 is different than the insert sold with the Q4.. It is way quieter. I dont have a decible meeter, but using my ears I would guess:

Stock Q4 = 96 DB
Stock Kawi = 76 Db
Q4 with quiet insert = 82 DB it made a huge difference

 

I would love to have something like that on my Muzzy!

 

Where do you buy the inserts, I have the Powercore 4 on mine and would like to be able to choose how obscene the sound is.

Do you know the part number? I tried to find on FMF site and failed.

 

You can find them on ebay or the website Tiger mentioned in the end of his first post. I'm getting one for the Q4.

 

I looked on ebay.. they dont look like mine.. I would get one from WRP Woods Rider Parts.com if u get one.. I have a feeling fmf makes a different variety of inserts.. I just lucked out.. it looks weird.. its tapered like a bulb at the end with a baffle and screen.. nothing like any of the pics ive seen on ebay here a pic

mine is a 1 1/8 inch made for powercore titanium or pc4

another link http://www.ridemx.co.uk/Moto_Cross/S...27_Insert.html

you gotta cut the screen right before the baffle to fit cuz the q4 has a baffle and theres just enough room without the screen. I have a feeling this was just an accident but wow.. very very quiet.. Im hoping someone will get one and share with me the excitement of having a q4 that is almost as quiet as stock.. I feel special now.. I have the quietest performance exhaust out there.. by accident...