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Making stock "S" exhaust quieter

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I live in a quiet neighborhood and I'm looking for a way to make my DRZ400s stock exhaust a little quieter. Does anyone know if wrapping the spark arrestor in some fiberglass exhaust packing material would be safe and effective? I know there isn't much room in there, but it seems like it might help... How much would it affect performance?

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Bwaaaaaahahahahahaaaaaaaa!!!!

I'm sorry, but that right there is funny...

In case you're serious, some have said that a FMF Powerbomb makes any exhaust more quiet. I cannot verify this claim. That, and keep your rpm's down when riding around your neighborhood.

I would not recommend putting anything behind the spark arrestor. It's an area that needs to be open for exhaust flow.

Seriously, though, how can anyone complain about a stock S exhaust? It's whisper quiet!

Another thought- Maybe you could graft on an exhaust from a WR450, or the new off-road Kawasaki? The exhaust outlet on that thing is smaller than your pinky finger

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ha the stock exhaust is quiet ive started my bike twice by mistake didint hear it running

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The stock s sounds like a lawn mower, actually i think my s is quieter than my lawn mower!:thumbsup:

As stated earlier, just stay off the gas in the neighborhood. It's good to be quiet, but your bike is already very quiet. Doing anything else to quiet your bike will kill it's performance even more.

Mike :thumbsup: :thumbsup:

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Guys, I know what the stock exhaust sounds like. I also know that hindering exhaust flow affects performance. I kindly ask that people refrain from posting their opinions on these obvious issues.

All I'm asking is if it would be safe (for people and the engine) and effective to add some packing in the spark arrestor compartment.

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Yes, you can do it. I would suggest to get packing designed for a muffler and merely use 'home insulation'. Be careful when removing the muffler tip, there is a gasket there and you cannot buy it as a single part, only comes with a complete muffler, same goes with the exhaust tip. After you have wrapped the spark arrestor screen, use stainless steel wire around the packing to hold it in place, tighter will make it quieter than looser. Not too tight as you do not want to crush the spark arrestor screen.

Worse case is you do not like the packing and you remove it. No harm, no foul.

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Yes, you can do it. I would suggest to get packing designed for a muffler and merely use 'home insulation'. Be careful when removing the muffler tip, there is a gasket there and you cannot buy it as a single part, only comes with a complete muffler, same goes with the exhaust tip. After you have wrapped the spark arrestor screen, use stainless steel wire around the packing to hold it in place, tighter will make it quieter than looser. Not too tight as you do not want to crush the spark arrestor screen.

Worse case is you do not like the packing and you remove it. No harm, no foul.

+1 on this idea.... I have the FMF Q2 and it is a louder than the stock S exhaust, but maybe the FMF repacking material may help your stocker get quieter.

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My first question is did you buy your bike used? If so has someone modified the exhaust that is making it louder. Check your end cap to make sure it has not been drilled bigger. Take the end cap off and make sure the baffles have not been drilled through. The reason I ask this is because I run an E exhaust on my S. I have two E exhausts that I bought off ebay. One is unmodified and the other I drilled out the end cap and all 3 of the baffles in side the exhaust. It is loud! If you have verified your exhaust is stock unmodified my suggestion is for you to lug your bike through your neighborhood. By lug I mean ride in a high gear and run the engine at a low RPM. Once out of your neighborhood let it Rip. One more note. As loud as my modified E exhaust is it still is not as loud as some of the Harley's I see on the road. I was on my ST 1300 this summer and a Harley came off the on ramp right in front of me. His bike was so loud it felt like someone was beating me in the chest with a baseball bat. I would not modify your stock exhaust to make it quieter. You will loose performance and possibly damage your engine.

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Yes, you can do it. I would suggest to get packing designed for a muffler and merely use 'home insulation'. Be careful when removing the muffler tip, there is a gasket there and you cannot buy it as a single part, only comes with a complete muffler, same goes with the exhaust tip. After you have wrapped the spark arrestor screen, use stainless steel wire around the packing to hold it in place, tighter will make it quieter than looser. Not too tight as you do not want to crush the spark arrestor screen.

Worse case is you do not like the packing and you remove it. No harm, no foul.

William, thanks for the advice. I think I'll give that a try. The best part of this approach is that it is easily reversible! I plan to remove this extra packing when I take the bike offroad.

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My first question is did you buy your bike used? If so has someone modified the exhaust that is making it louder. Check your end cap to make sure it has not been drilled bigger. Take the end cap off and make sure the baffles have not been drilled through. The reason I ask this is because I run an E exhaust on my S. I have two E exhausts that I bought off ebay. One is unmodified and the other I drilled out the end cap and all 3 of the baffles in side the exhaust. It is loud! If you have verified your exhaust is stock unmodified my suggestion is for you to lug your bike through your neighborhood. By lug I mean ride in a high gear and run the engine at a low RPM. Once out of your neighborhood let it Rip. One more note. As loud as my modified E exhaust is it still is not as loud as some of the Harley's I see on the road. I was on my ST 1300 this summer and a Harley came off the on ramp right in front of me. His bike was so loud it felt like someone was beating me in the chest with a baseball bat. I would not modify your stock exhaust to make it quieter. You will loose performance and possibly damage your engine.

Dhuber,

I did buy my bike slightly used, but I'm sure everthing is still stock. I agree that the stock exhaust is relatively quiet for a dirt bike. However, it is still very loud compared to the bicycles, scooters and electric golf carts in my neighborhood. I ride very conservatively around town and nobody has complained yet. However, if I can drop another 1-2 dB with $10 worth of packing material, it might be worth it.

Thanks for the feedback. -kevin

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I live in a quiet neighborhood and I'm looking for a way to make my DRZ400s stock exhaust a little quieter. Does anyone know if wrapping the spark arrestor in some fiberglass exhaust packing material would be safe and effective? I know there isn't much room in there, but it seems like it might help... How much would it affect performance?

Hi kg, :thumbsup:

Can you remove the end cap and post a pic of the inside of your muffler as well as a pic of the end cap? That way we can see if your exhaust has been modified.

Looking into the end, an unmodified muffler will have about a 1 inch diameter tube protruding out of the center of a partition and will have a perforated inner wall with a thin layer of compressed sound deadening material between it and the outer casing.

Here's a pic of the cross section of an unmodified stock muffler so you'll have an idea of what it's supposed to look like in there...

shorty2.jpg

If your muffler is unmodified and you want to make it quieter. DO NOT wrap the spark arrestor screen with anything! You could make your engine overheat very rapidly.

There is one thing you could do safely and that is to get a small piece of perforated sheet metal about 5"x 12" that is thin enough to easily form into a tube, but yet springy enough to want to open back up. Put a 1/2 inch layer of muffler packing material around the outside of the tube and insert it into your muffler. Then release it to expand and pin the packing material around the inner circumfrence.

That should considerably quieten your stock exhaust without impeding the flow.:thumbsup:

Take Care,

Greg

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Hi kg, :thumbsup:

Can you remove the end cap and post a pic of the inside of your muffler as well as a pic of the end cap? That way we can see if your exhaust has been modified.

Looking into the end, an unmodified muffler will have about a 1 inch diameter tube protruding out of the center of a partition and will have a perforated inner wall with a thin layer of compressed sound deadening material between it and the outer casing.

Here's a pic of the cross section of an unmodified stock muffler so you'll have an idea of what it's supposed to look like in there...

shorty2.jpg

If your muffler is unmodified and you want to make it quieter. DO NOT wrap the spark arrestor screen with anything! You could make your engine overheat very rapidly.

There is one thing you could do safely and that is to get a small piece of perforated sheet metal about 5"x 12" that is thin enough to easily form into a tube, but yet springy enough to want to open back up. Put a 1/2 inch layer of muffler packing material around the outside of the tube and insert it into your muffler. Then release it to expand and pin the packing material around the inner circumfrence.

That should considerably quieten your stock exhaust without impeding the flow.:thumbsup:

Take Care,

Greg

Greg, thanks for the advice. I'm sure my exhaust has not been modified. You have a good point about overheating the engine. I was afraid of something like that... Your idea with the "tube" sounds interesting, but I wanted something that was easily reversible when I took the bike off-road. After hearing everyone's feedback, I think I'm going to leave things as they are (stock).

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I would not worry about the bike overheating, actually, overheating is more common with a open pipe. Just do not go grazy with the packing. Too much and your bike will not idle at all! Start out with just a few layers. If you think you need more, then try it. Use as little as you can.

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Hi William, :thumbsup:

I'm gonna have to disagree with you here... :thumbsup:

Muffler packing is not designed to pass exhaust through it.

It is only designed to absorb the sound of the exhaust pulses as the exhaust passes by it.

In a typical packed muffler... the exhaust passes down the middle through perforated tubing, and the packing surrounds the tubing to absorb the sound... but no exhaust actually passes through the packing...

cobracore2.jpg

Carbon particles carried by the exhaust get caught in the packing and can clog it up. I know this to be true, because I've seen how the dense and heavy with carbon muffler packing can get.

Even the stock spark arrestor screen should be checked every once in a while for carbon accumulation and cleaned. :thumbsup: .

Take Care,

Greg

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LOL, Yes, I know that, but it will not cause the engine to over heat. The muffler may get a little warmer than normal, but not much. If the screen is covered with packing, it will need to be changed regularly. I doubt it will clog, rather I would expect it to break down due to the heat and velocity of exhaust fumes and eventually 'blow out'.

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