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Sound checktoday, need quiter muffler than stock!

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Hi,

Today we had a sound test at our local track. The noise was to much so we had to get a new license with lower db's.

They have made sound check system of 20.000 euro with a container where you have to put your bike in and the sound is measurte at full throttle with a max of 120 db in the container.

I had a akrapovic system on my 08 rmz 450 and produces 127 db at full throttle.

Then I put the stock system on it with the powerboll (europian version) and it produces 129 DB!!!

So i have to go 9 db lower than stock!

There was only one fourstroke of 25 at the testday that was under the 120, it was a ktm 250F with a enduro demper on it. it just passed it barrely.

Most stock 2-strokes passed it.

So my question, wich muffler produces the lowest db availble on the market?

We are also gonna try to make a muffler ourselfs that is quiet enough.

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I used a hgs a few years ago which when you looked down the end was fluted?? I think thats the way to describe it! Basicly about and inch down inside the silencer there were 4 raised lips this really did kill the noise under full load and reguarly passed a standard noise test at 93/94 db.

Interesting what you say about the stock pipe i always thought they where very quite untill i pulled up at my local sand pit/quary come track last week and Carl Nunn was riding there on his stock RMZ and man that was loud under full load!

(assume as you euro you know who i mean!)

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Hi,

Today we had a sound test at our local track. The noise was to much so we had to get a new license with lower db's.

They have made sound check system of 20.000 euro with a container where you have to put your bike in and the sound is measurte at full throttle with a max of 120 db in the container.

I had a akrapovic system on my 08 rmz 450 and produces 127 db at full throttle.

Then I put the stock system on it with the powerboll (europian version) and it produces 129 DB!!!

So i have to go 9 db lower than stock!

There was only one fourstroke of 25 at the testday that was under the 120, it was a ktm 250F with a enduro demper on it. it just passed it barrely.

Most stock 2-strokes passed it.

So my question, wich muffler produces the lowest db availble on the market?

We are also gonna try to make a muffler ourselfs that is quiet enough.

I thought akrapovic makes a quiet insert for all their pipes??

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Yes, there is already is db-killer from akrapovic in it. but it is not enough.

Our local track has become very strict with the sound regulations with the town next to it. full throttle with 120 db is very low.. if stock system is at 129... yikes

So anybody know what the quietist muffler is? or a modification to the stock system perhaps...

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Oh yeah what also was nice to try, first test with the akrapovic is runs nice at high rev. when i put the stock syste back on it, on run like crap at high rpm with lots of popping. There was also a new KXF and CRF 450's and at high rpm inm stock form then didn't sound that good also, maybe beacuse of the efi?

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So anybody know what the quietist muffler is? or a modification to the stock system perhaps...

FMF makes the Q series of mufflers that are supposed to be very quiet and I think they also have a quiet insert available for them. After changing to a much quieter pipe I would think you will be in need of a Power Commander and a remap to get it running properly.

Mark

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Was reading my manual today, noticed on page 20-31 (2008) the following:

"Muffler Silenser: 14351-28H00"

-Steve

PS That is how they spelled it.

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thats weired eh, i think ours are measured at 4000rpm and our new limit is 94db, so keen to see what happens sunday.

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anyone know how the rmz 450 runs with a FMF Q with a power bomb. It,s a bit more affordable than the megabomb header.Hopefully a fair bit quieter than stock with more pull on top.

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