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Discussion Starter #1
So, where i am from, there is a generalized law the states

"the allowable decibel reading for motorcycles is less than 92 decibels"
Now my main questions would be. 92 decibels at what? idle? 5000 rpm? 7000 rpm?

secondly, how do they actually measure this? a foot from the exhaust? 5 feet from the exhaust? 12 feet?

Seems to be a pretty grey area.

Upon digging more, i found a slightly more detailed by-law in a near by city (kinda... about 500 miles away)

Violators in excess of 92 dbA at idle for all motorcycles
Violators in excess of 96 dbA at 2000 rpm for motorcycles having less than 3 cylinders or more than 4 cylinders
Violators in excess of 100 dbA at 5000 rpm for motorcycles with 3 or 4 cylinders.
Normally i will ride with the stage 2 baffle in, as i normally fire it up at 5am to commute to work, and dont like to be the asshole neighbor that wakes everyone up. But occasionally i like to run around without the baffles in.

with all this in mind, i run the m4 GP, and i have drivin past the police with the baffle out, around 3k RPM, and typically, they wont even look. (Though i have had one officer look at me, roll up his window, and continue writing the ticket to the car he had pulled over)

I cant seem to find any solid facts on how far away they measure the DB, nor what the m4gp (or even stock exhaust for that matter) put out on idle.

Anyone have any experience with this? or any numbers that may be of relevance?

Im thinking of picking up a db meter to test it out, but would be unsure where to place it.

(PS i saw the shootout that shows the difference exhaust db's... but that only says the increases at an unspecified "cruise" and "WOT", not the actual number they found.)
 

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Don't know about where you're from, but here, in the technical definition of the law, it would be 92 db at any time (i.e. probably at redline under load?), but here, it's not even kind of enforced and if they did enforce it, they'd have to pull over about 25,000 Harleys before they ever even looked at me :O
 

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Discussion Starter #3
Don't know about where you're from, but here, in the technical definition of the law, it would be 92 db at any time (i.e. probably at redline under load?), but here, it's not even kind of enforced and if they did enforce it, they'd have to pull over about 25,000 Harleys before they ever even looked at me :O

well considering the stock exhaust says 93db at 7000 rpm.. thats a little harsh i would say.

I havent heard of any of these laws being enforced here, apart from the occasional buddy of a buddy who knows this guy who got the ticket. BUT, im still curious on where the measurement would be from? even a few feet would make a pretty big difference and potentially be the difference of pass or fail.

edit: and im from BC Canada.
 

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well considering the stock exhaust says 93db at 7000 rpm.. thats a little harsh i would say.
Yeah, I can't imagine that's the case, then...I mean 92db really isn't that much anyway; I was just saying that I know that's how they write the laws in Michigan.
 

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SAE 1287 is fairly common way to measure. Here's a short article on how it's done.

How To Measure Exhaust Sound | Hot Bike

But you should talk with your local constable and see how they do it. If they do it. Most officers have no clue how to do it or what the law actually is so they don't bother. If it's really loud they may write a citation or a fix it ticket and make you prove it's within limits just to be a pain in your ass.

There are other standards and other methods that are accepted but not standardized as well as this one.
 

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So, where i am from, there is a generalized law the states



Now my main questions would be. 92 decibels at what? idle? 5000 rpm? 7000 rpm?

secondly, how do they actually measure this? a foot from the exhaust? 5 feet from the exhaust? 12 feet?

Seems to be a pretty grey area.

Upon digging more, i found a slightly more detailed by-law in a near by city (kinda... about 500 miles away)



Normally i will ride with the stage 2 baffle in, as i normally fire it up at 5am to commute to work, and dont like to be the asshole neighbor that wakes everyone up. But occasionally i like to run around without the baffles in.

with all this in mind, i run the m4 GP, and i have drivin past the police with the baffle out, around 3k RPM, and typically, they wont even look. (Though i have had one officer look at me, roll up his window, and continue writing the ticket to the car he had pulled over)

I cant seem to find any solid facts on how far away they measure the DB, nor what the m4gp (or even stock exhaust for that matter) put out on idle.

Anyone have any experience with this? or any numbers that may be of relevance?

Im thinking of picking up a db meter to test it out, but would be unsure where to place it.

(PS i saw the shootout that shows the difference exhaust db's... but that only says the increases at an unspecified "cruise" and "WOT", not the actual number they found.)
Not trying to be a d*ck..... the most fundamental answer to this question is very straightforward. If you think you need to check the volume, it's too loud. You already know this. :coocoo Everything after that, is justification.

'How far over the line can I go?'
'Why did they pick on me?'

It's a losing argument with me.

I don't really care why you should choose to do so; nor do I spend any of my time trying to sort out the 'benefits' of a louder exhaust.

In the simplest terms, the loud exhaust that draws attention, draws all sorts of attention.:oops:If you want to excercise your right to misbehave, go for it. You can't really have it both ways.

Sooner or later you will probably end up in a discussion with 'the man' about the noise you are making. When that happens, take your lumps and move on. If at the same time you have problems with your liscense, or registration, insurance, tires, lights....... it just piles on. A simple courtesy stop can become so much more in the blink of an eye. Just remember, you set the stage for what follows.

OEM exhausts are ignored by LEOs. I can go faster, in more places with the OEM exhaust than I ever could with the M4 that was on the bike when I bought it. Since I am not routinely stopped, there is much more slack available in other areas. In effect, I am presumed 'innocent'.

0.02
 

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Discussion Starter #7 (Edited)
Not trying to be a d*ck..... the most fundamental answer to this question is very straightforward. If you think you need to check the volume, it's too loud. You already know this. :coocoo Everything after that, is justification.

'How far over the line can I go?'
'Why did they pick on me?'

It's a losing argument with me.

I don't really care why you should choose to do so; nor do I spend any of my time trying to sort out the 'benefits' of a louder exhaust.

In the simplest terms, the loud exhaust that draws attention, draws all sorts of attention.:oops:If you want to excercise your right to misbehave, go for it. You can't really have it both ways.

Sooner or later you will probably end up in a discussion with 'the man' about the noise you are making. When that happens, take your lumps and move on. If at the same time you have problems with your liscense, or registration, insurance, tires, lights....... it just piles on. A simple courtesy stop can become so much more in the blink of an eye. Just remember, you set the stage for what follows.

OEM exhausts are ignored by LEOs. I can go faster, in more places with the OEM exhaust than I ever could with the M4 that was on the bike when I bought it. Since I am not routinely stopped, there is much more slack available in other areas. In effect, I am presumed 'innocent'.

0.02
in no way do i find that rude, no worries there.

i mostly ask, not becasue i ride like an ass, but because i want to be informed on the situation.

i put the exhaust on, because it was in my price range, and i really liked the look of it compared to stock. I couldnt hear it before i bought it, so it wasnt purchased on that factor. (not many sport bikes around here at all.. infact, mine is the only white zx6r sold at the dealership here through 2013 and 2014. at least as of 2 weeks ago. there is ONE other white 650r however.)

from a youtube video that tested the m4 on a zx6r, it looks like the m4 with the stage 2 baffle WOULD actually pass the 100db at 5000 rpm mark thats used in a few nearby cities, as it was 101db at 7000.

I ride fairly civilized, and have been pulled over once before with the m4, but they made no mention about the noise, and in the end i was set free after a friendly chat with the officer.

if i did get a notice, i would put the stage 2 in, and get it inspected. if it still failed, i would revert back to stock and start looking at the quieter exhausts.

I more or less just like to be informed as possible about what i own.

I know whats allowed and not allowed on my bike, the biggest grey area i could find was my exhaust, and i wanted to figure out where it stands.

To put it into perspective however, at work, a guy owns an old harley softail thats been bored out, with screamin eagle pipes no baffles. It overpowers my bike massively in the DB range. his next door neighbor is a police officer, and he has never had issues. Even so, i still want to test my bike to see where its at compared to whats allowed. No baffle is obviously too loud.. but i want to actually know if it passes with the stage 2.


now that you mention it actually... i find myself being better behaved with my m4 on, simply because its louder, and draws more attention. makes me ride it at the speed limit to keep the noise down and not draw too much attention.
 

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Check with the LEOs directly.... ask them how they measure sound. The OEM systems are built to pass the 'tightest' sound regulations of any market the bike is sold into. Quite frequently, that is considerably less than what is actually allowed in some other market.

US law for sound is so convoluted it's state by state, and not consistent at all. This is why it's best to ask a local 'expert'.
 

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Discussion Starter #9
Check with the LEOs directly.... ask them how they measure sound. The OEM systems are built to pass the 'tightest' sound regulations of any market the bike is sold into. Quite frequently, that is considerably less than what is actually allowed in some other market.

US law for sound is so convoluted it's state by state, and not consistent at all. This is why it's best to ask a local 'expert'.
Fair enough. Perhaps ill ask the next officer i see, when i'm NOT on my bike.

thanks for the input.
 
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