Need help to make my wr450 quieter

when I bought my 04 WR450 it had all the baffles removed from the exhaust, Ran great but was way to loud. I recently entered an off road race and was sound tested(they want 96db max). Mine tested at 112db:thumbsdn: , since this I have ordered the pro moto billet silencer (from the TT store). My question is this, I have read many articles on keeping our bikes quieter and many refer to muffler packing. When I look inside my muffler it is just a big open can with a spark arrester, no packing of any kind that I can see. Now is this something that was removed by the previous owner or should there be no packing. If there is supposed to be packing how do I go about repacking my muffler and am I missing any other parts?:thumbsup::)

Some stock mufflers are baffled without packing. Some have packing, and it sounds like yours was gutted. If it does not have metal baffles that were cut out on the inside you are missing the internal parts to pack around. The packing would go around a perforated cylinder kinda like looking down a glass pack muffler. So it sounds like you might be better off just to replace the muffler with a quiet one. Glad to see you are getting it quieter and the AMA has finally pulled their heads out and took a listen.

on mine I had to drill out some rivits then slide out all of the guts. I went down to the local bike shop and bought a repack kit which consisted of insulation and took some safey wire made a criss cross pattern to hold the insulation on reinserted the guts and re-rivited togather. Real easy to do took less then 20 minutes to do.

...is this something that was removed by the previous owner or should there be no packing.
There is no packing in a stock, '04 WR muffler. The PMB insert should work.

I have an '04 WR450 also, its got the stock muffler without the endcap. I thought it was a little loud, but 112db REALLY?

Just for clarification, my stock muffler has a round, almost chrome body, not oval brushed alum like the '05+.

I have an '04 WR450 also, its got the stock muffler without the endcap. I thought it was a little loud, but 112db REALLY?

Just for clarification, my stock muffler has a round, almost chrome body, not oval brushed alum like the '05+.

Here is a photo of my bike with the stock 04 muffler.

DSC01163.jpg

Sorry for the small photo. Still learning.

Buy a GYTR exhaust insert, I have one ....I will shhot a picture of it in a few minutes. I believe they are about 35 bucks.I believe it quiets down to 89 db's(read very quiet).

Dave

Your muffler doesn't have any packing in it. It uses baffles inside the can to reduce noise. This is different than the removable end plug that came with the bike. You can get a GYT-R endcap for about 40 bucks that will really reduce the noise level without drastically affecting the power output. I have been using one of these on my '99 for years. The design of your muffler and mine are essentially the same except for outer finish.

I do the sound checks for a Dual Sport Club I belong to and have measured my noise levels and those of other Wr4xxs and they usually are around 90-92 dBA. Keep in mind that if the sound level meter isn't set properly the decibel reading could vary greatly from my numbers. The meter needs to be set at slow response and "A" weighting. The AMA publishes a guide for sound level testing. We follow those guidelines for consistency. If the test is performed another way , it's no telling what kind of readings you will get.

Here are the pictures of the gytr end plug.gytr pics 001.jpg

gytr pics 002.jpg

gytr pics 003.jpg

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