Quiet pipes?

So what's the quietest one can make pipes anyway?

My neighbor says we might be able to rebaffle my OEM exhaust with fiberglass, but how much would that quiet the bike down compared to how it is? The pipes are OEM with OEM baffles.

My goal is to make the bike as quiet as possible. I doubt I could get it repo quiet but if I can, that'd be amazing.

More quiet than stock? Next to impossible I'd say. You would have to cut open the mufflers and design a new baffle system, then seal the mufflers somehow. Or purchase some different mufflers that are quieter.

If your stock KZ750 mufflers are similar to those on my KZ650 they are not packed with fiberglass. They have a metal baffle system engineered into them. See below. Ed

Nessism wrote: More quiet than stock? Next to impossible I'd say. You would have to cut open the mufflers and design a new baffle system, then seal the mufflers somehow. Or purchase some different mufflers that are quieter.

Well, I know the stock is going to be impossible to make quieter... Are there any super quiet exhausts I could get?

I know what I'm asking is basically opposite the norm, but I never claimed to be normal...

650ed wrote: If your stock KZ750 mufflers are similar to those on my KZ650 they are not packed with fiberglass. They have a metal baffle system engineered into them. See below. Ed

I'm aware that it's a metal baffle, not fiberglass. I was saying my neighbor who's a better mechanic than I am tells me we could pack it with fiberglass to make the stock quieter... But if there are some aftermarket pipes that can make it whisper quiet I'd like to go that route. Though my stock pipes are not like yours at least in shape. Mine is an LTD, so the pipes flare out like a megaphone.

At any rate I'd like to get the pipes about as quiet as possible. Yes I am aware of the possibility of backpressure issues and I'm willing to rejet if necessary.

If your bike is the LTD I'd bet that it wouldn't bee too difficult to fit a stock exhaust system from another KZ 750 model. Better yet would be to find someone locally who has another KZ750 to see if it's any quieter.
My bet is that going quieter than stock is impossible. Keep in mind that another source of engine sound is the intake opening at the air box. Does your bike have the original intake baffle?
Bill

Supertrapp makes mufflers that are tunable. That is, you you install fewer or more disks at the outlet. Mostly it's for adjusting the fuel air mixture. Fewer disks enriches and more disks leans it out. As a side effect fewer disks also makes it quieter. Probably stands to reason that a 2 into 2 system would be quieter than a 2 into 1 on account of having twice as much muffler.

The 750E muffler system is a direct bolt-on. The mufflers are about 6" longer than the Ltd.
I put a set on my 81 650-CSR but I have no idea if they are quieter. see link in my signature.

KZQ wrote: If your bike is the LTD I'd bet that it wouldn't bee too difficult to fit a stock exhaust system from another KZ 750 model. Better yet would be to find someone locally who has another KZ750 to see if it's any quieter.
My bet is that going quieter than stock is impossible. Keep in mind that another source of engine sound is the intake opening at the air box. Does your bike have the original intake baffle?
Bill

Nobody in the area has KZs outside of this one drag team that races all over Georgia, (and they nearly always win)... but those guys are like all KZ1000s and higher, all with big bores and performance parts, and damn the noise.

Yes my bike has the original everything. Only thing not OEM on my bike is the sissy bar, and even then I installed it myself and so I still have the grab bar that it replaced.

I'm also aware that the engine will still produce noise, but I'd like to make it as quiet as feasible... I really doubt I'll silence the whole thing. Afterall, explosions are explosions, and they're hard to suppress completely. Cars have a lot more material to them to keep them quiet.

Still would like to see just how quiet I can push it.
.

Bowman wrote: Supertrapp makes mufflers that are tunable. That is, you you install fewer or more disks at the outlet. Mostly it's for adjusting the fuel air mixture. Fewer disks enriches and more disks leans it out. As a side effect fewer disks also makes it quieter. Probably stands to reason that a 2 into 2 system would be quieter than a 2 into 1 on account of having twice as much muffler.

Well, this is a 4 cylinder bike, so I guess 4 into 4?

I built a stealth 2 stroke MX bike. Fab'd a flowmaster style silencer insert, wrapped the expansion chamber with header wrap and installed a pipe guard. The header wrap made a pretty big difference because alot of sound resonates through the pipe not just out the back end.

You'll also get intake noise too.

Hi Setton,
I see that your bike doesn't have an intake baffle.
Sorry
Bill

I like a quiet bike and all but trying to reduce the sound level below OEM levels seems extreme.

I think your best bet is to look for some more modern mufflers. Harley cast off's are typically easy to find and cheap. The stock headpipes are double wall so I'd keep those and work on the muffler side. Understand that more quiet pipes will also (most likely) be more restrictive so you may lose power and have to rejet.