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How to get better sound from stock mufflers?

  • Thread starter Thread starter ty998
  • Start date Start date
T

ty998

Guest
Bike 81 GS650 Gx

I would like a more robust sound from my stock exhausts. I want the exhaust note to have more definition and possibly a little louder, but not the kind that attracts the cops from 4 blocks away. Anyone know what I mean?

Someone told me that I could drill some small holes around the exhaust on the end of the muffler and it would give me that small increase of audibility that I am looking for. Is this a real solution or not. I don't want to spend the cash on a custom exhaust muffler(s) right now.

This suggestion sounds like it rates right up there with duct tape, but also sounds plausible. :lol:

It's hard to undrill holes. LOL!
 
Don't drill holes... Don't remove the baffle. If your stock exhaust is in good shape there might be someone out there that wants it. You can get chrome emgo mufflers for about $60 each. They will give you the deep sound you are looking for with removable baffles so you can add or remove fiberglass. You can get much cheaper mufflers in the $20-$30 range but they are much louder and do not have removable baffles.
 
ty998 said:
It's hard to undrill holes. LOL!
Click to expand...

^^^^^ This. 650's don't get a lot of love in the aftermarket world so you may want to find a set of beat up pipes that you can experiment on and leave your stock ones (assuming they are in good shape) alone, in case you end up with problems.
 
The stock exhaust/mufflers are in great shape.
I thought the Kerker exhausts are just for people who want to scare old people to death and annoy communities? :)

Also if I went with a Kerker 4 n 1 then I assume I would have to rejet to make good use of them. Yes?

The Emgo mufflers sound like a good option once I have the $

Tkent02, I will keep you at top of list if I decide to replace stock
 
The original owner of my '82 1100 did the "mod" you suggested. Bike can't be tuned as well as others I've been a part of. Probably need to rejet the carbs.

When I come off the throttle, it sounds like the 4th of July.

Don't Do It!
 
Doldrums said:
The original owner of my '82 1100 did the "mod" you suggested. Bike can't be tuned as well as others I've been a part of. Probably need to rejet the carbs.

When I come off the throttle, it sounds like the 4th of July.

Don't Do It!
Click to expand...
Yes, if you do not tune the carbs you will not like the performance.
 
ty998 said:
I thought the Kerker exhausts are just for people who want to scare old people to death and annoy communities? :)
Click to expand...
Only if you remove the baffle and run a straight pipe. :eek:


ty998 said:
Also if I went with a Kerker 4 n 1 then I assume I would have to rejet to make good use of them. Yes?
Click to expand...
Yes. But, ... you would probably also have to do that with a drilled stock system or the EMGO mufflers or Harley mufflers, if you chose to go that route.
Virtually anything that enables the system to flow more than stock is going to require re-jetting.
icon_shrug.gif


.
 
Listen to Steve, he knows his stuff. Any change will require rejetting to make it right.
And my Kerker is louder than stock, but not annoying. It was until I repacked it, which reduced the sound by 10 dB (by half). I used a sound meter, before and after, so my results are accurate.
 
Best offer I have heard so far is from tkent, I would take up his offer in a heart beat.
I assume he has the kerker on his bike right now, hence it would be jetted for the pipe, ask him to throw in the jets/needles he has in there for you, and send your stock ones back to him, that way all the guess work is taken out of the deal for you, Tom knows his stuff and you better believe his bike goes like stink and is set up properly.
All you have to do is transfer them into your bike along with the pipe.
4 into 1's sound glorious.
 
I have "un-drilled" my exhaust before.

I had to tediously cut over a dozen small pieces of sheet metal out, round them off, then spot welded each one back over the holes. Then I RTV'ed over the whole thing to seal it up, and blacked it out.
It wasn't easy...barely enough room to fit my welder tip at that angle.
 
Last edited:
Flyboy said:
Tom knows his stuff and you better believe his bike goes like stink and is set up properly.
Click to expand...

Ha, Ha, Ha, LOL woo hoo ROFL!!!

Actually it runs like crap, gets much worse gas mileage than the 1100, and I haven't ridden it in months because it's so slow, and leaks oil everywhere above the base gasket. It does not have the Kerker on it, it has the little Herdly take offs, and it is not tuned correctly for them at all.

SouthJefferson-20110418-00007.jpg


I need to redo the top end, and tune it, but I don't want to tune it for the hardly mufflers, they are too quiet and too restrictive. The Kerker is one option, but I would prefer the stock pipes for this one. Alas, I have no such stock pipes.
 
Thanks for feedback.

In summary:
1. People who tell you to drill holes in things to solve a problem are generally wrong.
2. Any muffler change would require rejetting, which I am not interested in right now.
3. Since I have no major $ to put into this I should enjoy my stock exhaust and its moderate sound. :D

However, I do have one outstanding, long-time question on this:
I understand why you would want to update jetting and exhaust if you increase/change the air/fuel intake. But why is it so critical to update the jetting if all you are doing is upgrading the muffler? What is the harm in releiving more back pressure from the engine? Obviously you won't be improving your performance, but where are the major problems here that seem to be insinuated?

Preparing to be educated... :eek:
 
Because you are allowing more air to flow. In order to keep the air to fuel ratio the same, when you increase the amount of air you must also increase the amount of fuel. And vice versa. Hence a rejet is required. In your case, it would run too lean and could possible hole a piston. Certainly not run correctly, nor as strong as before the drilling began.
 
When you modify the exhaust to flow more air you are altering the fuel/air ratio. More air leaving = more air going in, not as much with just exhaust mods but it does increase some. The only way to compensate for it is to rejet the carbs to add more fuel. These bikes were jetted on the lean side to start with so it dosn't require much change to make them too lean.

Very simple explanation but I hope it helps.
 
dr_fosg8 said:
The only way to compensate for it is to rejet the carbs to add more fuel. These bikes were jetted on the lean side to start with so it dosn't require much change to make them too lean.
Click to expand...

This, but the pipe makes less difference than the intake, and usually only at high RPM and power or WOT so likely a little bit bigger main jet is all that is required, maybe shim the needles a tad higher.
 
koolaid_kid said:
Because you are allowing more air to flow. In order to keep the air to fuel ratio the same, when you increase the amount of air you must also increase the amount of fuel. And vice versa. Hence a rejet is required. In your case, it would run too lean and could possible hole a piston. Certainly not run correctly, nor as strong as before the drilling began.
Click to expand...

Apparently I am just really dense.
In my case I am putting the same amount of air and fuel into the engine (stock). If the muffler was upgraded to flow more air out why wouldn't it simply do a more effecient job of allowing pressure to exit and that's all? All we are changing here (hypothetically) is the exhaust output. In this scenario I would assume that the engine would perform the same.

Thanks for your patience on this. I would like to understand it.
 
dr_fosg8 said:
When you modify the exhaust to flow more air you are altering the fuel/air ratio. More air leaving = more air going in, not as much with just exhaust mods but it does increase some. The only way to compensate for it is to rejet the carbs to add more fuel. These bikes were jetted on the lean side to start with so it dosn't require much change to make them too lean.

Very simple explanation but I hope it helps.
Click to expand...

OK. I am going to take this explanation on faith.
I am keeping my stock exhaust and avoiding this whole delima. :lol:
 
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