'Noise Law' Compliant Mufflers

[AJsarge]

Living in Hawaii I have to deal with...
" Exhausts can't be modified, altered, or reparied in such a way that the noise emitted by the vehicle is inreased above that emitted by the vehicle as originally equipped from the factory. "
That...

I'm seeing the Two Bros setup on the forums a lot, and loving it just as much. But, I have to deal with above law, and have my bike inspected every year. Are there any options I have for replacing the stock mufflers with compliant ones that look/work better?

And I'm well aware that I could go illegal and simply put the stock ones on for the inspection, then replace them again when the bike passes. I'm sure the board has rules against discussing illegal mods.

I missed this part too, if it matters.
" Maximum allowable A-weighted sound levels range from 61dBA to 91dBA based on measurements taken from 20-50 feet at speeds ranging from 25-60mph. "

 

[QwickFliCk]

i would check out the yoshimura pipes i kno they have some legal ones that meet standards im not sure for the fz...plus they are pretty quiet compared to the two brothers or an m4

 

[QwickFliCk]

also found this: akrapovic
Akrapovic Street Legal Slip-On Exhaust for FZ6 04-09 - Exhaust - Slip/Bolt-ons - Solo Moto Parts

 

[4drfocus]

Just cut open your stock muffler, gut it out and weld it back together.

 

[mikw73]

Dynatech (and maybe others) makes exhaust cone inserts that go in the pipe between the headers and the muffler. Google "exhaust cone insert". They're generally intended to quiet racecars down to the allowed track volume, but some people use them on bikes, so I hear. They do adversely affect performance, so I would guess you're better off performance-wise staying stock. You'd want to get a decibel meter and test once you're done. And a power commander (the street-legal one, since legality is the issue here, right?) and a dyno run wouldn't be a bad idea. I like the stock can, but I think there may be a market for a facelift kit. Though the heat shield does look pretty good considering what's under it.


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[ChevyFazer]

Fu** da po po fu** da po po fu** da po po what.........



bad advice

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[Andz]

also found this: akrapovic
Akrapovic Street Legal Slip-On Exhaust for FZ6 04-09 - Exhaust - Slip/Bolt-ons - Solo Moto Parts

My Akros with the dB killers were pretty quiet. Unfortunately I don't know where the dB killers are... luckily noise is the LAST thing cops worry about here.

 

[Phil_RC_1]

I've seen slip-ons that say "Meets EPA noise regulations". Knowing a little about the physics of how mufflers work, and these are typically smaller then the stock can, I have to assume that they would not dyno as well as your stock muffler, or at best they would be equal to the stock system. A slip-on that didn't increase performance is a waste of a good $400-$600 to me.

I think 4drfocus has the best idea for your specific application. Gutt or semi-gutt the stock can. It won't be as loud as most aftermarket cans and it will still have the stock appearance and probably a slight performance increase.

 

[ChevyFazer]

I've seen slip-ons that say "Meets EPA noise regulations". Knowing a little about the physics of how mufflers work, and these are typically smaller then the stock can, I have to assume that they would not dyno as well as your stock muffler, or at best they would be equal to the stock system. A slip-on that didn't increase performance is a waste of a good $400-$600 to me.

I think 4drfocus has the best idea for your specific application. Gutt or semi-gutt the stock can. It won't be as loud as most aftermarket cans and it will still have the stock appearance and probably a slight performance increase.

Actually a gutted can is louder than all slip ons unless you get race slip ons and even then the noise is about the same. I know because mine is gutted. Although he could drill it out, for better sound but a gutted can is real loud.

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[Phil_RC_1]

Actually a gutted can is louder than all slip ons unless you get race slip ons and even then the noise is about the same. I know because mine is gutted. Although he could drill it out, for better sound but a gutted can is real loud.

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I can believe that. I suppose I was thinking more along the lines of what skodilak did in this thread rather then a completely gutted can. If you were to do what skodilak did but use exit tubes the same diameter as stock, you would probably be quieter then most aftermarket cans but have improved performance over stock. Drilling a few holes in the stock can baffles without opening it would meet my definition of a "semi-gutt".