Topic: Aftermarket Muffler with Stock Headers

[Dereks618]

Hey guys,
   I have a 75’ CB550F that I am slowly getting back “road worthy”. One hangup I’m having is trying to find a recommendation on a new muffler, I have the stock 4 into 1 exhaust setup. All I can seem to find online is either a new complete header/muffler setup for BIG $$$ or cheap $25 cone slip-ons. My original headers are still in good shape. If anyone had any suggestions for a decent slip-on I would really appreciate it.
Thanks!!

[BomberMann650]

Oem “slip ons” are going to be rare unobtanium as well.  Like my lucky yoshimura canister.

Best best would be to check out cone engineerings catalogue.  Pick a resonator you like.  And enlist some help fabricating a mid pipe to suit your taste.

Since it’s now winter in the northern hemisphere, your local ace clubman speed shop might welcome the job.

[Stev-o]

+1 Cone Eng....

http://www.coneeng.com/motorcycle_components.html

[RandomOrbit]

Looks Like Mac has a slip-on for CB550f. It's $200 though, for $325 you can get a stainless steel Delkevic system.

[Ace Blackwell]

I’ve read where muffler size or restriction can affect carb settings. Did I understand that correctly? If so is there any special considerations i would need to think about   when buying a muffler  for my 77CB550F?  I’m also getting ready to redo the carbs. Should i tweak one to work with the other?

Thanks

[BomberMann650]

Exhaust design has the ultimate effect on air speed leaving the combustion chamber.  As well as it’s ability to scavenge unspent hydrocarbons back into the boom room.

Shrinking and expanding pipe sizes, size and shape of the resonator are the tools we have to make this effect.

[Dereks618]

Thanks for the reply’s everyone. I have been to the cone engineering site and thought about making my own can. I’m a welder by trade so tig welding my own stainless muffler has crossed my mind. I just didn’t know were to start ie diameter,length, inlet, outlet etc. Guess I’m worried about messing up the back pressure.

[Stev-o]

Thanks for the reply’s everyone. I have been to the cone engineering site and thought about making my own can. I’m a welder by trade so tig welding my own stainless muffler has crossed my mind. I just didn’t know were to start ie diameter,length, inlet, outlet etc. Guess I’m worried about messing up the back pressure.

I have a 76 550F with the stock exhaust system. It is very restrictive [and quiet] so if you dont want to deal with rejetting, fabricate a muffler that will create some back pressure.

[BomberMann650]

Oh but the rewards of a modified inlet and exhaust system are so much fun.

My 550 is piped, jetted, cammed, and port polished.  It’s a different animal now than before.

[TwoTired]

I’ve read where muffler size or restriction can affect carb settings. Did I understand that correctly? If so is there any special considerations i would need to think about   when buying a muffler  for my 77CB550F?  I’m also getting ready to redo the carbs. Should i tweak one to work with the other?

Exhaust flow and pressure profiles effect engine mixture needs.  For example, consider the F a K variants of the same CB550 engine.  Using the very same intake system, only the exhaust is different between these models, causing and engine requirements change.  K and F carb setups differ in the slide needle profile, position, emulsion tube dimensions, and the main jet size.

Don't be surprised if your F muffler replacement, doesn't work better with the richer set up of the K model carbs.

Cheers,

[seanbarney41]

I have found that changes in length in diameter have much more effect on carburetion than the amount of baffling.

[Ace Blackwell]

I’ve seen several on 4into1 website. I prefer a quieter bike so I’ll probably check in that area.  Does one need a long style to quiet down the bike or are the smaller ones baffled pretty good?

[BomberMann650]

I’ve seen several on 4into1 website. I prefer a quieter bike so I’ll probably check in that area.  Does one need a long style to quiet down the bike or are the smaller ones baffled pretty good?

A larger, chambered, baffled, and insulated muffler will have more decibel reduction than your general moto exhaust pipe.

[TwoTired]

I’ve seen several on 4into1 website. I prefer a quieter bike so I’ll probably check in that area.  Does one need a long style to quiet down the bike or are the smaller ones baffled pretty good?

significant muffler design factors:

Chamber volume
Exit area
Baffling placement and material.

There are aerodynamic principles at work inside a muffler creating drag and pressure build up.
Unless you make your own, you won't have much choice in the matter of internal design.  Offerings are limited, and none actually characterized or quantified performance parameters with measurements.

I did glance at the 4into 1 site for a while.  It sure looks like they are mostly presenting style choices, rather than noise level choices.

All the MAC mufflers I've heard on the 550 were certainly louder than stock.  I believe they equate more noise with "high performance".  I've never been impressed with the chrome longevity of the MAC, either.  Definitely made to a price point.

The good news is that they offer parts for old bikes at all, I suppose.

Cheers,

[BomberMann650]

Some suggested reading!

http://www.enginelabs.com/engine-tech/exhaust/performance-exhaust-system-design-and-theory/

We are all seeking that right sound that announces itself like a fight song for our preferred automotive demographic, and those seeking the utmost performance require tuned lengths and forms to achieve the desired power delivery.

[Ace Blackwell]

Thanks Bombermann.  Was interesting reading.  Little more detailed than I could keep up with.   

I think I’m going to go for a nice and shiny muffler with a lot cool odd angles!!!  Lol

[BomberMann650]

Too many Bends negatively alter flow.

KISS rule applies

[Ace Blackwell]

Actually I'm a little more sensible than buying strictly on appearance, but I did have a few questions.  Does length affect motor cycle performance?  I've noticed "shortys"  that look to have promise.  Also is the cone Vs reverse cone just an appearance choice?

Thanks

[BomberMann650]

Length needs to be proportioned to a number divisible by the speed of sound
General rule of thumb; prime numbers - if you’re trying to be sonically balanced.

Try to think of it as an instrument.  Bigger chamber; deeper tone.  Open bell, tapers, cylinder - all have a unique acoustic quality.  In addition to effecting exhaust gas speed and volume.

Making a set of “shorty” drag pipes to work on a CB (or any bike) is no small feat.  The internal diameter of the pipe has to be a precise width to match the short length of character.  Since we’re dealing with a very specific pressure wave coming out the port.
The intake jetting and cam setup to get the most out of short pipes is far more radical than jetting for a cool looking resonator braaap can.

Not to mention, open shorty’s are obscenely loud, and known to irritate riders on longer rides

[gwallis]

Make your own...

Bought the end baffle from Carpy and the tail pipe from Auto Zone.

[Ace Blackwell]

gwallis, I'll consider it.  Was that your bike.  Looked nice.

With grand son, right now I'm having trouble finding time to paint seat pan or getting my painted Speedo/Tach back together. Can't imagine building a muffler.

I did see where 4into1.com had reproduction mufflers they claim sound like original.  Sounds promising but also sounds like 200$ lol.   Time will tell.

Thanks

[gwallis]

Yes... that is my bike and I have another as well.

The build is not very hard at all.  Get the tail pipe at Auto zone and cut to length.  Make sure that the inside diameter matches your outside diameter of your collector.  I purchased the chrome end baffle from Carpy's website and fashioned a 'Lollipop' in the middle of the baffle out of a very large thumb screw.

A Lollipop is a large washer or thumbscrew that sits in the middle of the exhaust stream in order to apply slightly more back pressure.  The end result is somewhat deeper tones in the exhaust note.  The Honda Racing Team used to do this back in 70's in order to increase low end torque.

I have no idea if my setup helps performance... I just like the way it sounds!