What is going on with 4t exhaust tuning?

ohiomotoxer
Posts
634
Joined
2/12/2017
Location
Cleveland, OH US
2/11/2026 7:38pm Edited Date/Time 2/11/2026 7:39pm
Airbox intake, engine mechanical noise also contribute to overall db. When I worked at supertrapp/kerker we needed to be at 72db on one project. We could...

Airbox intake, engine mechanical noise also contribute to overall db. When I worked at supertrapp/kerker we needed to be at 72db on one project. We could make the exhaust output quiet and flow well but the airbox and engine noise was something we couldnt address.  Perf tube hole %, length, volume of the can and the type of packing are the only thing that will dampen the exhaust pulse wave. 

OldTech wrote:
Ok you've had experience building pipes and I'm interested in what they are doing here. Besides the resonance chambers, they have obviously added a lot of...

Ok you've had experience building pipes and I'm interested in what they are doing here. Besides the resonance chambers, they have obviously added a lot of length. So much that if it were a front center port like a Honda, that can would be at least two feet past the fender. So, let's assume they are trying to break up the pulse wave, wouldn't that also cancel scavenging or using pulse wave for tuning? They went through a lot of trouble to NOT make a better muffler.

Without seeing dyno and ignition curves, mapping or flow data it's hard to give an educated answer.  There is...allot of voodoo going on there.

  I would say it is quite the psych job. 

 

2
thewrizzle
Posts
489
Joined
4/27/2018
Location
Rochester, WA US
2/11/2026 7:39pm
thewrizzle wrote:
Why do you post shit like you know it before googling it? Using the 113 db sound limit post race and using “your” math you are telling...

Why do you post shit like you know it before googling it? 
Using the 113 db sound limit post race and using “your” math you are telling me that inside of a stadium at a supercross race we are only hearing approx 41db? What is an example of 41db? When I search for this information it ranges from light rain-babbling brook-average home noise- computer hum… my experience says that you can only communicate by yelling at the person next to you. That is far from a non issue.

yak651 wrote:

Exactly, guy is delusional thinking people in row 6 are only experiencing 40db. 

Someone download the NIOSH sound level meter on their phone this weekend and let’s see

If I end up going to the AX in Reno this weekend I will do that.

1
OwenJakes
Posts
1684
Joined
6/30/2023
Location
sebree, KY US
2/12/2026 9:11am
OwenJakes wrote:

I’ll ask again in here and maybe get a better answer. Why do we need to lower sound limits for professional events again?

cloverdale wrote:
Actually, it is the manufactures that are pushing for reduced sounds (executive level staff), not the AMA as most people would assume. That said, it has...

Actually, it is the manufactures that are pushing for reduced sounds (executive level staff), not the AMA as most people would assume. That said, it has turned out to be more challenging than originally anticipated and those the subsequent need to push the new sound requirements from the original 2026 implementation to 2027. From a bottom-line standpoint one might surmise that lower sound translates into better PR and ultimately increased bike sales. So... unless there happens to be executive level staff on this forum you probably will not obtain a formal vetted answer to your question.

You and aees gave perspectives and replies that are good. Thanks. That’s basically what I was wondering. 

I’m not sure why this immediately turned into “muh riding areas” and stuff. If the vision behind our sporting events is more conversational then sure. That makes sense. When the noise discussion happens like 90% of the time it’s framed as some kind of impending danger to health and sustainability. 

Thanks for not calling me a narcissist too🤣🤣

9
OwenJakes
Posts
1684
Joined
6/30/2023
Location
sebree, KY US
2/12/2026 9:16am
DonM wrote:
Only one person is in a twilight zone and it is you….but of course a narcissist like you would only assume everyone’s opinions are wrong except...

Only one person is in a twilight zone and it is you….but of course a narcissist like you would only assume everyone’s opinions are wrong except theirs…

OwenJakes wrote:

Articulate my perspective back to me. 

(Thanks for the psychiatric diagnosis too)

DonM wrote:

Downvotes dude downvotes….if that doesn’t clue you in I can’t help you….

Downvote = bad 


-youIMG 1342 0

16

The Shop

shortty761
Posts
694
Joined
4/2/2024
Location
Newport News, VA US
2/12/2026 9:46am
OwenJakes wrote:
Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards...

Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards. OEMs, FMF, PC, etc. should focus on making better packing and designs for consumers and the professionals should have factory parts. 

I have a feeling most of the people on this forum are the “turn that racket down” type crowd.

People that go to motor sports events enjoy the sound; weather it’s a dirtbike or a race car, there is nothing else to it. Without that, it's just not as exciting.


Hearing the engine rev while a rider throws a whip. Feeling the vibration in your body at a NASCAR race. 

40 riders all on the gate rev bombed before the start of a Pro National is a magical feeling.

It you go to a Supercross or Pro Motocross race and have complained "it's too loud" then you probably need to change your tampon.

Now a local track, I totally get it.

They don't worry about noise at NASCAR races, Moto GP, Monster Trucks, Local Mud Bogs/Tractor Pulls, Indy Car racing, Drag Racing, I could go on and on.

Formula E failed because no sound sucks.

12
TAUTOG
Posts
1588
Joined
1/27/2023
Location
Mohrsville, PA US
2/12/2026 9:57am
OwenJakes wrote:
Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards...

Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards. OEMs, FMF, PC, etc. should focus on making better packing and designs for consumers and the professionals should have factory parts. 

shortty761 wrote:
I have a feeling most of the people on this forum are the “turn that racket down” type crowd.People that go to motor sports events enjoy...

I have a feeling most of the people on this forum are the “turn that racket down” type crowd.

People that go to motor sports events enjoy the sound; weather it’s a dirtbike or a race car, there is nothing else to it. Without that, it's just not as exciting.


Hearing the engine rev while a rider throws a whip. Feeling the vibration in your body at a NASCAR race. 

40 riders all on the gate rev bombed before the start of a Pro National is a magical feeling.

It you go to a Supercross or Pro Motocross race and have complained "it's too loud" then you probably need to change your tampon.

Now a local track, I totally get it.

They don't worry about noise at NASCAR races, Moto GP, Monster Trucks, Local Mud Bogs/Tractor Pulls, Indy Car racing, Drag Racing, I could go on and on.

Formula E failed because no sound sucks.

Bro, your last sentence. You just said this:

1396 0.jpg?VersionId=b0HVWUULvzIzj87EI6
2
crpilot
Posts
23
Joined
12/24/2016
Location
Nashotah, WI US
2/12/2026 9:59am Edited Date/Time 2/12/2026 10:00am
OwenJakes wrote:

I’ll ask again in here and maybe get a better answer. Why do we need to lower sound limits for professional events again?

HonDawg17 wrote:
Especially in supercross when the previous weekend had unregulated monster trucks at 150+ decibels.. For professional races sound shouldn't even be considered a problem. now every...

Especially in supercross when the previous weekend had unregulated monster trucks at 150+ decibels.. For professional races sound shouldn't even be considered a problem. now every single weekend for regular riders and a lot more riders on those weekends, that makes sense to bring the sound down.

Flatliner wrote:
This is exactly what I've ben thinking.   Outdoors,  yea.  Sound. Monster jam rolls in, as loud as they want... yet we need to quiet the bikes...

This is exactly what I've ben thinking.   Outdoors,  yea.  Sound.

 

Monster jam rolls in, as loud as they want... yet we need to quiet the bikes for professional racing?

 

It's a fair enough question to be asked.

Think about the bigger picture:  Its all about the trickle down effect on production bikes/aftermarket parts.  No one is going down to their local monster truck dealership to buy one and roll down first street with open headers....zero race development impact on production cars.  On the other hand, the exhausts on the race bikes ARE being marketed to the general public (amatures) and there is a benefit for ALL riders if development includes a cap on DB limits that translates to more places open to ride (or not closing more land due to sound...)

5
shortty761
Posts
694
Joined
4/2/2024
Location
Newport News, VA US
2/12/2026 10:39am
OwenJakes wrote:
Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards...

Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards. OEMs, FMF, PC, etc. should focus on making better packing and designs for consumers and the professionals should have factory parts. 

shortty761 wrote:
I have a feeling most of the people on this forum are the “turn that racket down” type crowd.People that go to motor sports events enjoy...

I have a feeling most of the people on this forum are the “turn that racket down” type crowd.

People that go to motor sports events enjoy the sound; weather it’s a dirtbike or a race car, there is nothing else to it. Without that, it's just not as exciting.


Hearing the engine rev while a rider throws a whip. Feeling the vibration in your body at a NASCAR race. 

40 riders all on the gate rev bombed before the start of a Pro National is a magical feeling.

It you go to a Supercross or Pro Motocross race and have complained "it's too loud" then you probably need to change your tampon.

Now a local track, I totally get it.

They don't worry about noise at NASCAR races, Moto GP, Monster Trucks, Local Mud Bogs/Tractor Pulls, Indy Car racing, Drag Racing, I could go on and on.

Formula E failed because no sound sucks.

TAUTOG wrote:
Bro, your last sentence. You just said this:

Bro, your last sentence. You just said this:

1396 0.jpg?VersionId=b0HVWUULvzIzj87EI6

It was sarcasm bro

3
OwenJakes
Posts
1684
Joined
6/30/2023
Location
sebree, KY US
2/12/2026 2:47pm
OwenJakes wrote:
Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards...

Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards. OEMs, FMF, PC, etc. should focus on making better packing and designs for consumers and the professionals should have factory parts. 

shortty761 wrote:
I have a feeling most of the people on this forum are the “turn that racket down” type crowd.People that go to motor sports events enjoy...

I have a feeling most of the people on this forum are the “turn that racket down” type crowd.

People that go to motor sports events enjoy the sound; weather it’s a dirtbike or a race car, there is nothing else to it. Without that, it's just not as exciting.


Hearing the engine rev while a rider throws a whip. Feeling the vibration in your body at a NASCAR race. 

40 riders all on the gate rev bombed before the start of a Pro National is a magical feeling.

It you go to a Supercross or Pro Motocross race and have complained "it's too loud" then you probably need to change your tampon.

Now a local track, I totally get it.

They don't worry about noise at NASCAR races, Moto GP, Monster Trucks, Local Mud Bogs/Tractor Pulls, Indy Car racing, Drag Racing, I could go on and on.

Formula E failed because no sound sucks.

For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. 

Sound is 20% of our perception. 

nothing gets me juiced like a 450 cracked open.

1
10
OFalk280
Posts
310
Joined
6/27/2012
Location
Elwood, IL US
2/12/2026 4:40pm
826 wrote:
Motocross is one of the only professional motorsports where the general public can buy essentially the same equipment that is raced at the professional level.Thus, quieter...

Motocross is one of the only professional motorsports where the general public can buy essentially the same equipment that is raced at the professional level.

Thus, quieter bikes at the professional level equals quieter bikes for consumers which means hopefully we can keep more riding areas open.  It's literally that simple, it's a battle that we've been fighting for decades and is nothing new.

Before someone jumps in and tries to look smart and says "insurance is what's closing tracks" please realize this sport is MUCH larger than just motocross tracks.  Most bikes that are sold will be ridden in farm fields, back yard tracks, some sand pit with houses nearby etc. etc.  they will never touch a true motocross track.  I know that's hard to fathom when you are hardcore moto enough to be on a forum like this but it's the truth.  Having quieter bikes helps keep those places open. 

This is exactly the reason. The professional sound regulation is a result of the manufacturers efforts to reduce the noise levels of their production bikes for non-professional use. A massive chunk of the reason for this comes from the need for it in Europe, and the manufacturers don’t want to build a North American spec vs a Global spec bike anymore. Bringing a consistent value to the sound limit globally (hence why the AMA is jumping all the way to FIM/MXGP’s dB level) allows the manufacturers to have a more “level” playing field among themselves if they just build a global spec bike.


I also believe that I read or heard somewhere relating to this that the rule is being pushed by the manufacturers themselves, though some of them weren’t quite ready for it to hit this year so it got pushed back.

3
OFalk280
Posts
310
Joined
6/27/2012
Location
Elwood, IL US
2/12/2026 4:49pm
thewrizzle wrote:
Why do you post shit like you know it before googling it? Using the 113 db sound limit post race and using “your” math you are telling...

Why do you post shit like you know it before googling it? 
Using the 113 db sound limit post race and using “your” math you are telling me that inside of a stadium at a supercross race we are only hearing approx 41db? What is an example of 41db? When I search for this information it ranges from light rain-babbling brook-average home noise- computer hum… my experience says that you can only communicate by yelling at the person next to you. That is far from a non issue.

yak651 wrote:

Exactly, guy is delusional thinking people in row 6 are only experiencing 40db. 

Someone download the NIOSH sound level meter on their phone this weekend and let’s see

At St. Louis SMX playoffs last year I was in around the 10th row of the second from the floor section, and my Apple Watch was giving me noise safety alerts the entire time of 100+dB. I wore hearing protection throughout the event because it genuinely hurt my ears.

5
1
yamathumb
Posts
167
Joined
3/11/2025
Location
Redding, CA US
2/12/2026 6:05pm Edited Date/Time 2/12/2026 6:06pm

It just plain looks more correct for the pipe to be in that area. It's what we are used to visually,  surprised the aftermarket didn't do that immediately in 2010. (This would make a 2010 yz450 with the tornado pipe run significantly better as the tuned length of those bikes is a bad compromise, hence the solution in 2014.)

1
bodycast
Posts
301
Joined
1/18/2020
Location
Monroe, NC US
2/12/2026 6:18pm
OwenJakes wrote:
Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards...

Anyways I have no idea why pro bikes are being muffled for pro events meanwhile local stuff is wide open. I think it should be backwards. OEMs, FMF, PC, etc. should focus on making better packing and designs for consumers and the professionals should have factory parts. 

shortty761 wrote:
I have a feeling most of the people on this forum are the “turn that racket down” type crowd.People that go to motor sports events enjoy...

I have a feeling most of the people on this forum are the “turn that racket down” type crowd.

People that go to motor sports events enjoy the sound; weather it’s a dirtbike or a race car, there is nothing else to it. Without that, it's just not as exciting.


Hearing the engine rev while a rider throws a whip. Feeling the vibration in your body at a NASCAR race. 

40 riders all on the gate rev bombed before the start of a Pro National is a magical feeling.

It you go to a Supercross or Pro Motocross race and have complained "it's too loud" then you probably need to change your tampon.

Now a local track, I totally get it.

They don't worry about noise at NASCAR races, Moto GP, Monster Trucks, Local Mud Bogs/Tractor Pulls, Indy Car racing, Drag Racing, I could go on and on.

Formula E failed because no sound sucks.

OwenJakes wrote:
For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. Sound is 20% of our perception. nothing...

For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. 

Sound is 20% of our perception. 

nothing gets me juiced like a 450 cracked open.

Or being an internet troll.

OwenJakes
Posts
1684
Joined
6/30/2023
Location
sebree, KY US
2/12/2026 6:24pm
shortty761 wrote:
I have a feeling most of the people on this forum are the “turn that racket down” type crowd.People that go to motor sports events enjoy...

I have a feeling most of the people on this forum are the “turn that racket down” type crowd.

People that go to motor sports events enjoy the sound; weather it’s a dirtbike or a race car, there is nothing else to it. Without that, it's just not as exciting.


Hearing the engine rev while a rider throws a whip. Feeling the vibration in your body at a NASCAR race. 

40 riders all on the gate rev bombed before the start of a Pro National is a magical feeling.

It you go to a Supercross or Pro Motocross race and have complained "it's too loud" then you probably need to change your tampon.

Now a local track, I totally get it.

They don't worry about noise at NASCAR races, Moto GP, Monster Trucks, Local Mud Bogs/Tractor Pulls, Indy Car racing, Drag Racing, I could go on and on.

Formula E failed because no sound sucks.

OwenJakes wrote:
For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. Sound is 20% of our perception. nothing...

For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. 

Sound is 20% of our perception. 

nothing gets me juiced like a 450 cracked open.

bodycast wrote:

Or being an internet troll.

It’s funny because I’m genuinely not but anyone over 30 cannot comprehend when disagreement and banter combine. The elder mind cannot process alternative thought. 

1
10
2/12/2026 8:18pm

My 20 hour 500 EXC came with a straight through MX pipe. It was unbearable just sitting on it at idle let alone riding it slowly. I found a new takeoff 501 can that still had the peferated end cap. Put it on, and instant relief. Bike it still plenty fast to lift a wheelie in 1st through 3rd without much effort.  If I could make it even quieter I'd do it. 

What all is being done to address airbox noise in Europe? Or is exhaust the main culprit? 

1
Titan1
Posts
9409
Joined
2/3/2010
Location
Lehi, UT US
2/12/2026 8:21pm Edited Date/Time 2/12/2026 8:51pm
OwenJakes wrote:
For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. Sound is 20% of our perception. nothing...

For anyone that thinks sound isn’t important, listen to music in your car then listen to a 100+ choir and band. 

Sound is 20% of our perception. 

nothing gets me juiced like a 450 cracked open.

bodycast wrote:

Or being an internet troll.

OwenJakes wrote:

It’s funny because I’m genuinely not but anyone over 30 cannot comprehend when disagreement and banter combine. The elder mind cannot process alternative thought. 

The arrogance of your ageism is nauseating….

1

Post a reply to: What is going on with 4t exhaust tuning?

The Latest