White Brothers E-Series Quiet Insert

Anyone used one of these? The local dealer can get me one for $40. Seems about average cost wise but will it help my bike pass noise? Here in CA the limit is 96dB. Went to the local OHV park last week. With FRESH packing (~1HR) and 6 discs my bike tested at 100.8dB. With 3 discs it tested at 98dB. Still too high and it's really choked up at that point. I was thinking about getting the insert to get it down a little more. The catalog claims it'll reduce sound 2-5dB. Does anyone have any info on these quiet inserts?

I don't have any figures on it. But I did get the E-Series quiet core insert. It did reduce the noise especially directionally. It pushes the sound down and back. But overall I didn't think it made a huge difference. I wish I could tell you if you would pass, but all I can say is that it might still be close. I ended up going back to stock. So, if you are interested I will sell you my quiet core insert for much less than $40.

agreed, besides directing the noise i didn't notice a bid differance. Although with mine it needs new packing and i'm running way more than 6 discs. There aren't any public trails anywhere near me so i don't have to worry about pissing anyone off except my neighbors when i ride around my yard...and i hate those neighbors.

I It did reduce the noise especially directionally. It pushes the sound down and back.

Fogive me 'cuz I have yet to see a picture of the insert but... If I still run the discs after installation how can the insert affect the directionality of the sound? Won't the gaps in the discs be the main factor in the direction of the sound waves?

Also I would be interested in buying it from you. I'll PM you.

Believe me I tried. The way it is designed there is no way you can put it on over any plates. It replaces all plates and end cap. It bolts directly on to the muffler.

depending on how many you run it will fit under the diffuser disks. the order that i have right now is muffler - quiet insert - disks (more than 12) end plate. As you can see from the link it looks like a diffuser disk but directs the sound down. If this is the only thing you are running then you won't pass a spark arrestor test...atleast i didn't. I'm guessing with 8-12 disks you could run this inside the disks or as the first disk bolted on.


I hope that makes sense.

The quiet core insert for my 2000 WR400 made very little difference, perhaps 1 db. Using the optional white bros 360° shroud which goes over the outside of the disks helps direct the sound away from the side of the bike, where the db meter will be. This will help for perhaps another 1db. All in all on my bike, using the e-series tapered head pipe and a recently re-stuffed muffler, running 12 disks and the 360° shroud, got me down to 97db. Removing disks made very little sound difference, but made the bike run very crappy. For events that I need to be tested, I unfortunately had to revert to a stuck muffler with a 1½" insert. The front of the muffler had to be slightly modified to accept the White Bros tapered head pipe, but it is the only way I could get legal and have a bit of power. The White Bros tapered head pipe is much better than a stock head pipe. When I do not have to be tested, I use the White Bros stock E-series muffler with the quiet core insert and 12 disks and the 360° shroud. It is pretty easy to switch out the mufflers for different events depending on the sound requirements, and I do not do any carb modifications when I change mufflers. The power these bikes make with the White Bros system is pretty impressive, and likewise can be pretty discouraging when the stock system is used. There is a company here in Phoenix called Quiet is Cool that makes some quality pipe inserts for a variety of bikes. They can be reached at www.quietiscool.com. (623-695-2013) If anybody knows of a good aftermarket system that makes great power and is 94/95db, let me know! Hope this helps you out. :thumbsup:

Well, I got the insert. Thanks Bentru for the offer but apparently my dealer is faster than even they thought. I am NOT happy with the quality of construction. It's just a crappy looking as you all indicated. I have yet to have it sound tested. Next week I think. How do you all run 12 discs? With 6 discs (no core insert) I was testing at 100.8 dB with absolutly fresh packing (on a YZ). I cut it down to 3 discs and got 98 dB but there's no way I wanna run the bike like that. I'm sure the stock exhaust will flow more than those damn 3 discs will.

Thanks for the quietiscool link. After seeing what I got for my $40 I've been thinking about making my own inset. I just haven't figured out where to get a good perforated tube....

Quiet is Cool can also help you out with the perforated internal muffler insert.

www.quietiscool.com. (623-695-2013)

97db is the very best I was able to get out of my White Bros muffler assembly and that is using the quiet core insert. Unfortunately, I reverted back to the stock muffler to get it quiet when needed. See my previous post.

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