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SMX League Adopts New Sound Rules For 2027 Season - Cycle News
Exhaust sound limits are reduced by 3 decibels starting with Anaheim for Supercross, Pro Motocross, and SMX. Should be a noticeable change to someone listening to hear the difference. Good improvement from the 2012 limit of 6 dB louder (115 decibels then). I know this has been in the works for a while, along with MXGP, but it's good to know they're actually doing something.
I would never describe 109 decibels as "quieter" but hopefully not as loud helps with the neighbors!
dB is logarithmic.....3dB is a lot to the ear.
This could actually be tough to accomplish.
3 dB is small but noticeable. Source: Difference in Noise Level and Perception of Change to Human Ear? | ResearchGate
As for changes, it just takes a longer silencer. It's tough to minimize static pressure drop & power loss. I'm curious what the dyno will show.
3db is barely noticeable... 6db is easy to hear the difference... 10db would sound "twice" as loud...
This is ignorant!! The week before, or the week after Supercross at nearly every venue. They have open header V8 monster trucks ripping in the same stadium and sound is not an issue.!! what are we doing here?
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When I was younger I would have thought this was stupid and gay. Now I realize its kind of nice. Hell you can barely hear a bike being ridden in the woods from a couple 100 ft away. Making it quieter can only help. It is a good trade off.
Agree this isn't an issue in stadiums. But even outdoor national tracks have legal issues & costs complying with noise laws.
And trickling down technology for all places to ride. Less sound = more ground.
Dumb! The smoke in the closed stadiums is a bigger deal than the sound!
Ever been to a NASCAR, F1, Indycar race?
Except how many stock exhausts stay on at local tracks. So many get dumped for the loudest fmf with no insert money can buy.
This lower standard allows tracks to test to it if that's what is legally required to stay open. If they don't need it, they can allow other silencers.
Then that is a track issue. Local tracks seem to do no favors for themselves when it comes to avoiding issues. Saying "hey if your exhaust is loud as hell we are kicking you out WITH a refund" is easy to say and enforce. The liability a lot of them expose themselves to with obstacles and not fixing obviously dangerous track conditions is another, but not the subject of this thread.
Seriously there is zero reason for sound spec for a national or supercross.
Make it for amateur racing and for the am national every bike must stock pass the 112 hell go 109 I don't care. But pro racing is a joke.
Or Monster Jam.
It's not really possible to silence monster trucks.
“They need to slow the bikes down!”
“Not like that!”
Ever hear of a muffler? They've been around for a hundred years. And I think sound rules in racing is stupid.
109db is NOT just an exhaust change.
It takes about 5 changes to the bike to meet the 27 requirements.
Back in the old days Blue Ribbon Coalition's tag line was "Less Sound, More Ground". They knew that cutting a few db's meant less hassles with keeping riding areas open. A lot of folks ran dBsnorkel's on their 2-strokes.. still see them around once in a blue moon.
I run the infamous OEM perferated end cap on my 500 EXC. My bike is still plenty loud, but without the headache-inducing roar from the straight-through FMF racing pipe that originally came on it. Perf end cap still has a mean tone to it that sounds cool to me. I can still easily get the front wheel in the air just by twisting the throttle.
Also love how the factory KTMs sound this past year.
Except we have been there already in Europe.
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*to be competitive.
Silencer, maybe tune the Helmholtz resonator frequency in the midpipe, compression, timing, fuel mapping, maybe add cooling capacity if the bike is running much harder.
Or just run a 2027 bike because they all meet it. Or a 2026 MXGP bike because they all meet it. No changes there.
No, they need something much more important to the accessibility of riding areas, legality, and neighbors' complaints: displacement limits
It’s just gonna choke out the bike a little more. They’ll be a hair slower.
2026 you need to buy a kit to Austrian bikes to meet the limit. 900 euro or so.
Airbox covers under seat, smaller exhaust hole, different mapping, different air filter cage.
Mine did 111 when I took away the air filter covers, ran 2-stroke filter cage and mapped it with GET SX1. Still OEM exhaust.
Factory bikes gained power. Stock, not so much.
My new 2027 450 SXF was like a 350 stock. Fucking slow.
OEM demanded it.
They don't want to run completely different platforms than production of they don't have to, not even in MXGP.
What you're currently hearing is a blown 572ci motor spinning to 9,000 rpm with a specialty muffler.
I guess you could make them bigger, but it won't change much.
Who are the people complaining about noise at a motocross event? Go to a NFL game (Cowboys excluded) in the same venue as Supercross and db will be much higher.
The new 350sxf with a dual injector and all these upgrades is going to be sick. But honestly, this bike is going to be amazing.
I have a question for everyone. What will a say 2020 or earlier bike (250,350,450) feel like compared to these newer sound restriction bikes feel like as far a power goes? Ktm is adding a dual injector to either add power to make up for something or just the refinements in technology require it.
?
The neighbors
Hangtown: Hangtown MX, Prairie City SVRA Under Threat - Cycle News
Washougal around 2005 spent over 6 figures monitoring noise levels to show compliance after not getting the conditional use permit approved.
Tyla Rattray private track shut down by county - Moto-Related - Motocross Forums / Message Boards - Vital MX
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I'm sure there are some examples but motocross tracks are located on purpose in very rural, sparsely populated areas where the land is cheap and loud motorcycles aren't bothering anyone. I've been to Glen Helen many times and it's right next to a prison maybe the inmates have been complaining too. With major manufacturers coming out with their e-bikes it won't take long before anything with a combustion engine will be banned and we all (not me) but everyone else is racing e-bikes and coming back to the pits to fire up their 120 db generator to recharge it.
Not meant as a ragebait, just my opinion: I dont really care tbh, those bikes sound more or less like "ass" anyways.
Now if MotoGP would get this quiet on the other hand... i would be mad af. Nothing sounds better
(they are still sitting at crazy 130db)
Post a reply to: New Exhaust Sound Limits for 2027: 3 Decibels Less