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2013 KTM 500 exc, FMF 4.1 Titanium 94db slip-on louder than KTM stock setup

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I have a 2013 KTM 500 exc.   My pipe needs repacking and I am thinking about buying FMF 4.1 Titanium slip-on and running it with the stock KTM header.    1. I am wondering if the FMF 4.1 Titanium 94db slip-on will be louder than the stock setup.     2.  Does anyone know what the Db  rating is for the KTM stock pipe?     Mark

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it most certainly will be louder than stock, even with the stock header.

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I have one with the mega bomb header and use the quite core....tried it with out core once....does not run any better but IS way loud.

It is louder with core in than the stock but not bad...the tone is low and deep.

The pull at full throttle and upper rpm is WAY stronger.

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I've got a 450XCW with the 4.1 exhaust and it's pretty loud even with the SA in there.

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I have a 2014 KTM 500exc with the FMF 4.1 slip on only, (Stock header) and at idle it is not that much louder than stock and on the gas it is a bit louder than stock.

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Loud pipes kill our rights.

You know I used to be on board with this but anymore I think it's BS. They just keep taking and taking and it's not due to loud pipes. Let's face it there are just those out there who have a vendeta against motorized recreation and no matter what you do they are not going to drop it. If it makes you feel better then have at it but I doubt it has any real effect on the fight for public land.

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You know I used to be on board with this but anymore I think it's BS. They just keep taking and taking and it's not due to loud pipes. Let's face it there are just those out there who have a vendeta against motorized recreation and no matter what you do they are not going to drop it. If it makes you feel better then have at it but I doubt it has any real effect on the fight for public land.

 

 

I can't tell you how true it is that noise closes riding areas.  When I was little we moved to an area with very few houses.  We rolled down the driveway and rode all day during summer and every day after school.  As more people built houses near by and moved in, they started calling the police because of the noise.  FF about 25 years and you cannot ride there at all anymore.  Some guys who lived near me bought several acres of land to make their own track, but nearby houses complained about the noise and the police told them stop or they would get a citation for noise.  Chad Reed had noise related legal troubles with his neighbors, read about it here:

 

http://www.tampabay.com/news/localgovernment/pasco-commissioners-blast-motocross-track-owner/1273896

 

In all of these cases, noise was the primary complaint.  If the bikes were as quiet as electrics, these would have all been non-issues.  Noise closes riding areas, the few that are left.  People who hear the bikes will complain to the local leaders, most of which do not ride, and they will pass laws to make it illegal to ride there.  If no one can hear you, they won't complain, and we can ride.  It happens all the  time, it happened where I live and it will happen to you too if we don't all keep our noise in check. 

 

Let me add;  if those county commissioners who have been dealing with Reed are ever approached with the idea of opening a public riding area within their area, what do you think their response is going to be after their experience with the noise complaints about Reed? 

Edited by sirthumpalot
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I can't tell you how true it is that noise closes riding areas.  When I was little we moved to an area with very few houses.  We rolled down the driveway and rode all day during summer and every day after school.  As more people built houses near by and moved in, they started calling the police because of the noise.  FF about 25 years and you cannot ride there at all anymore.  Some guys who lived near me bought several acres of land to make their own track, but nearby houses complained about the noise and the police told them stop or they would get a citation for noise.  Chad Reed had noise related legal troubles with his neighbors, read about it here:

 

http://www.tampabay.com/news/localgovernment/pasco-commissioners-blast-motocross-track-owner/1273896

 

In all of these cases, noise was the primary complaint.  If the bikes were as quiet as electrics, these would have all been non-issues.  Noise closes riding areas, the few that are left.  People who hear the bikes will complain to the local leaders, most of which do not ride, and they will pass laws to make it illegal to ride there.  If no one can hear you, they won't complain, and we can ride.  It happens all the  time, it happened where I live and it will happen to you too if we don't all keep our noise in check. 

 

Let me add;  if those county commissioners who have been dealing with Reed are ever approached with the idea of opening a public riding area within their area, what do you think their response is going to be after their experience with the noise complaints about Reed?

Yeah I get that. I don't even like loud pipes. I used to be an avid supporter of that philosophy but after watching what's transpired I think they are going to complain no matter what the sound level is. Anything over the background is too much in their mind. It's just an excuse. Bottom line is they don't like what you do. Perhaps in urban areas such as tracks it's a legitimate issue. Believe me the CBD is not going to stop their agenda if you put a q pipe on your bike.

Edited by PBDBLUE
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I think it's important to remember that we're fighting for our rights on multiple fronts.  One one side the over development of our home towns is causing noise complaints to be an issue.  On the other side the eco-nazzies are trying to lock all people out of all woods everywhere, and since our fun machines make noise, smoke and leave tracks that makes us an easy target.  Quiet exhausts keep people from knowing we're around, and out of sight is out of mind.  Politics makes strange bedfellows, and people who don't like our noise are happy to donate to the local eco-nazzi group who claims to only want to save bambi and her forest friends. 

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With the fmf slip-on, can you add the megabomb header after if you like? I see it says the powerparts slip-on only works with the stock header pipe.

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ALL aftermarket straight-through mufflers, under throttle, will be louder than the stock muffler, period.

At idle, it might be close to stock, but no one rides at idle.

 

There is no way to judge how loud it is from the riding position.

 

One of the reasons the KTM muffler is so quiet, is that it forces the sound waves to shorten, hence making them more suseptable to local materials absorption.

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"One of the reasons the KTM muffler is so quiet, is that it forces the sound waves to shorten, hence making them more suseptable to local materials absorption."

 

That makes no sense.

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I would love to put a pipe on my 500 but I'll be keeping it stock.  It has plenty of power and I like the stealth factor so I can ride close to million dollar homes.

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"One of the reasons the KTM muffler is so quiet, is that it forces the sound waves to shorten, hence making them more suseptable to local materials absorption."

 

That makes no sense.

 

So, I'm wrong, but you offer no proof.......now that makes no sense.

 

A long wave is harder to absorb than a short wave.

 

The stock muffler is not a straight through-type, it is an off-set type.

It mechanically changes the resonant waves inside the muffler, as well as dampening/absorbing them.

Part of the reason is destructive interferance; the absence of a standing wave.

 

The stock can is about as long as a 130 hz sound wave, but because it has a off-set internally, the tuning is much higher, and there is far less constructive interference (standing wave) inside the can.

 

So, the noise coming out of the end of the can, AND the noise coming out through the walls of the can, are both attenuated, and raised in frequency, and the sound that is raised in frequency is easier to absorb internally.

 

...but all of that mechanical interferance messes with the exahust pulses, lowering scavanging effeciency of the exhaust, lowering performance.

 

You can't have both, without dramatically increasing the size/weight of the muffler.

Edited by KRANNIE

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"One of the reasons the KTM muffler is so quiet, is that it forces the sound waves to shorten, hence making them more suseptable to local materials absorption."

 

That makes no sense.

 

I'm going to jump in here. Have you ever installed a reverse-flow 14" muffler on a hot rod? Then swap it out with a straight-through 14" muffler? The results are the same if you did this with a KTM scilencer.. OEM US being reverse flow design, aftermarket being the straight through design. 

 

Not only will the straight-through design be louder, it will drone like a SOB at certain RPMs.

 

This has proven itself over and over since the mid-50's...

 

.

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So, I'm wrong, but you offer no proof.......now that makes no sense.

 

A long wave is harder to absorb than a short wave.

 

The stock muffler is not a straight through-type, it is an off-set type.

It mechanically changes the resonant waves inside the muffler, as well as dampening/absorbing them.

Part of the reason is destructive interferance; the absence of a standing wave.

 

The stock can is about as long as a 130 hz sound wave, but because it has a off-set internally, the tuning is much higher, and there is far less constructive interference (standing wave) inside the can.

 

So, the noise coming out of the end of the can, AND the noise coming out through the walls of the can, are both attenuated, and raised in frequency, and the sound that is raised in frequency is easier to absorb internally.

 

...but all of that mechanical interferance messes with the exahust pulses, lowering scavanging effeciency of the exhaust, lowering performance.

 

You can't have both, without dramatically increasing the size/weight of the muffler.

 

Settle down there spunky.  I wasn't trying to prove or disprove anything.  Therefore, no proof given.  I just didn't understand how a muffler can "shorten" sound.  But now it is clear that you meant shorten the wavelength.  I claim that it can't do that either.  A muffler (a low pass filter, or in some cases a band pass filter) can block (reflect), transmit, or absorb sound (or individual sine wave components).  It cannot change a frequency.  That can only be accomplished by a non-linear device and a muffler does not qualify.  Nonetheless, I completely agree that the stock KTM muffler is quieter than just about any of the aftermarket models.

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