Topic: Making a Homemade Muffler?

[LoopsAndLogic]

After looking and reading about motorcycle 4 stroke mufflers, it seems it's very important to have chambers. I can't seem to find any pictures of the chamber system though!

I'm trying to make any exhaust system like the yosh edition for the CB400F. It pretty much is a header with what looks like a small designed muffler inside.

I have the proper piping and welding skills, but I can't find the design or the implementation that went into making those.

I'm not looking for a performance gain nor a power loss. I'm pretty much going for the looks and sound. And I do know I will have to rejet.

I also understand that there are many conditions to making the right size chamber for the best performance. But I'm not looking for performance

So, question one; Would anybody have pictures of the design of this chamber system?

Is there something I'm missing to the design of 4 stroke mufflers?

I can't seem to find any Yosh 400F pipes online..... Is there a place that might have them??

Also, could too much back pressure cause any engine damage or the other way around??

Any help is appreciated

LL

[masonryman]

Homemade pipes and muffler

Mark

[yd72]

Hi guys l am also interested to do DIY on the exhaust before I have lack of knowledge on this issue. It will be nice if anybody has done it before and post some photographs on the process of your DIY and post helpful wedsite on this.

Chris

[kslrr]

Hey Mman, those mufflers must weigh what, 5 pounds each!?

Loops, I believe not enough back pressure could burn your exhaust valves, at least it could happen in a standard American car engine, though these engines are tougher considering how many on this site are running open pipes.

When I get a chance, I will take pics of the custom 4-1 on my 350 and how I modified the baffle for just the right sound and back pressure.

[merc2dogs]

have you heard those mufflers yet?
 look like they will last!

 Also, not sure about short or open pipes burning valves, I've run dune buggies with short little stub pipes (3" max) with no problems for years, and piston engine aircraft commonly run very short stubs on the exhaust.


  I think a thick pipe for the muffler walls would give a lower tone, doesn't seem like it would 'rattle' as much.
 
 One of my old 750s, after getting rear ended by my brother and trashing a mint set of stock 4 into 4 pipes, all I could get was a header without muffler, $10. couldn't complain, tried a glass pack, but couldn't find one that both sounded right and had good enough bends to make it work, ended up using a turn out exhaust tip for a car, cutting two disks in 1/8 inch aluminum that just barely slipped into the end of it, same size as the collector (2.5 inch) so when the tip was on it held it in place
 Drilled a few small holes in each one, and bolted them together with short spacers between so the holes didn't line up, then opened up the holes till I had the sound and performance I wanted.  Think I ended up with three 1/2 inch holes in each one plus a 1/4 inch hole right in the middle (pilot hole for a hole saw) sounded good and ran great.

 should be easy enough to fit something similar in just about any cannister or tube you like the looks of.   

Ken. 
 
 

[masonryman]

No run yet, I think I might try to start it this weekend, I am sure there will be some tuning to get the flow and sound to the place I am looking for.

Mark

[chrisf]

Look at very small mufflers from a sport bikes, one of the first big ticket items they qualify to by. They are either the first things to get upgraded or the easiest thing to pull from a wrecked bike. One way or another, they are very cheap (and light) on ebay.

Why make what you can buy for $20 or so?

--Chris

[KB02]

Why make what you can buy for $20 or so?

Good point, unless you can make it for $15.   

[rhinoracer]

Why make what you can buy for $20 or so?

Good point, unless you can make it for $15.   

I get him. It's more about making them yourself and getting the exact look or sound you want than about saving a buck.

tried a glass pack, but couldn't find one that both sounded right and had good enough bends to make it work, ended up using a turn out exhaust tip for a car, cutting two disks in 1/8 inch aluminum that just barely slipped into the end of it, same size as the collector (2.5 inch) so when the tip was on it held it in place
 Drilled a few small holes in each one, and bolted them together with short spacers between so the holes didn't line up, then opened up the holes till I had the sound and performance I wanted.  Think I ended up with three 1/2 inch holes in each one plus a 1/4 inch hole right in the middle (pilot hole for a hole saw) sounded good and ran great.

 should be easy enough to fit something similar in just about any cannister or tube you like the looks of.   

Ken. 
 
 

You'll learn a lot in the process, like Ken said. It'll be trial and error until you arrive at where you want to be. Take a lot of pics, document it and let us know of your results.

Augusto

[LoopsAndLogic]

Hi kslrr,
  Pictures would be great! I really appreciate that.

I'm just looking for designs that somebody else did so I can get an idea of how much back pressure there muffler has.

I really don't want to buy any mufflers like on a sportbike. I like the look of just headers like the Yosh edition.

Looks different and I can get on my bike any side that I would want.

Here's some pics of the Yosh.

   Wheres TT when you need expert advise??

[chrisf]

Good point, unless you can make it for $15.   

I like it! But can can you make a 2 lbs Ti canister that can knock down the sound and have that non-rat rod flavor to it? I can't, that's for sure. I personally like the megaphone with a reverse. But to build one requires special tool and to buy one means shelling out $100.

Don't get me wrong, I'm all for making some things...

--Chris

[speedracer741]

This is the muffler design that I have been using on every bike I have owned for the last 10 years. Nothing fancy about them really, just a simple race style design. Of course I use them on the street The outer canister and end caps are aluminum (or aluminium  ) and the inner pipe is a length of steel exhaust tube available from any auto parts store, with a few hunderd holes in it. Inlet is 2-1/4" and outlet is 2-1/2". Because of the large size and resulting low heat and pressure, regular house insulation works very well and lasts forever. Fully assembled weight is under 3 lbs. The result is a very deep tone at idle and the sound never "cracks" all the way through the rev range. Haven't had any problems with the police either as it's quieter than one might think. A piece of bent tubing can be made at any exhaust shop for proper fitment on the bike. I have actually used the high quality stainless flex tube in the past with good results.

[merc2dogs]

 Lot of that depends on what you mean by rat rod.

 Also on what tools you have available, and are willing to buy.

 Most of the modern mufflers are looking more like old syle shop built mufflers, aluminum cans with pop riveted end plates etc
 My buddy has a Kaw, put a new muffler on it, and my first impression when I looked at it was $110 for that?

  with a shopping excursion to the nearest metal supplier I could find any aluminum or stainless tubes that I want for a body, a hole saw and plywood will produce a suitable hammerform blanks to form end plates from aluminum or stainless sheet, more tube for the outlets, and you could have a muffler that would be almost impossible to tell from a $150 factory can.
 All with a total cash outlay of maybe $50 plus the satisfaction of doing it yourself.

 Your double cone megaphone could be easily built at home using pretty simple tools, snips, jigsaw, hose clamps and welder, or pop rivet gun and drill.

 grab some posterboard and start experimenting.

 You'll get out of it what you put into it

Ken.

[Jim F]

my version of a (not home made but custom) is a mac header with a race only slip on from V&H
and then heated the collector to give me the high pipe look
sounds good and runs even better

Jim

[MoTo-BunnY]

How come no one seems to be using those SuperTrapp mufflers? Seems like they would work good and are adjustable. .  .. . a lot of the VW people I used to hang with loved them.

Do they sound weird on a bike or something?

just wonderin. .  . . .   

[LoopsAndLogic]

Hey kslrr, were you able to get those pictures?

The Supertrapps sound terrible!!!!

They only sound awesome one single cylinder Thumpers like in my avatar.

With the 4 cylinders, it really doesn't give the bike that nice sound......more like a low tone popper, and when rev'd, it sounds even worse.

This is coming from experience

So, now I have the idea of a silencer for the muffler. Either straight through with packing or chambered....... Going to have to think that one through.

But what about the scavenging effect that the muffler does for a fresh draw or air/fuel??? Has anybody had a bad effect from making there own muffler?

Well, I'm off to scetching my design for the muffler seen in my pic and I will post pictures of the finish product, as well as a short video clip.

[kslrr]

I pulled the baffle out last night.  It is so clogged with soot that it is difficult to see what I did.  I am going to blast it with my power washer this morning.  Just for fun I did start the bike with the open megaphone.  I love that sound .

[tsflstb]

I think the Supertrapp sounds pretty mean.  I also wanted a poor man's Yosh and stumbled across a Kerker header for sale.  It has a pretty long 2" collector so I ditched the megaphone and put a Supertrapp baffle on.  Gives it the racy look, but you can tune in all the backpressure you need.  Performance is the same as the megaphone and it weighs about 15 lbs. less.

[Jim F]

I use the super trapp on my GS 1100 E and its a nice baffled sound

just right


at least for that bike it is

[LoopsAndLogic]

How can you compare a SuperTrapp to a Kerker or MAC JK

If you have ever heard a Thumper with a Supertrapp, you would definitely say, "Yep, your right. It does sound better".

I've heard them on VF's, XR's, Yamaha XS, and CB F's.

I think I might remove my center stand and have the exhaust exit the left side. Routing it right behind the oil pan and coming slightly near the side of the rear tire. What do ya think???

tsflstb, Very nice 400F!!! I see your ignition has been moved to the seat latch lock. How on earth did you manage that???

You guys have anymore pics of custom made mufflers??

I appreciate all you help

[tsflstb]

tsflstb, Very nice 400F!!! I see your ignition has been moved to the seat latch lock. How on earth did you manage that???

Glad you like it, even with the second-rate muffler. 

That's not the original seat latch.  All the seat hardware got sawed off.  That would be some trick though huh?  The ignition is a cheap universal type from the auto parts store.  It has the starter wired up to it also. 

[LoopsAndLogic]

Starter too!!!

Man, that's nice. Did you by chance get that at AutoZone??

Real men don't have starters to start there bike, they kick it! 

Did you hand make that seat? All the shops around me want $125 - $250 because I added a hump to me seat, so they will have to start from scratch to make a cover.

Back to the subject!  I will be using Photoshop to plan my ideas for the muffler and I'll get back to yall.

LL

[kslrr]

Ok guys, after figuring out my taxes, filling them and paying them and after a busy weekend with my 4 boys and looking at houses, I have finally found the time to explain what mod's I made to my baffle and why (I also had to think back to the mid '80's to remember what I did).  Like I stated in other threads, the first owner had a custom 4-1 pipe made for this 350F (you will notice that the collector outlet is at least twice the diameter of the CB400F 4-1 stock pipes).

This first pic shows the collector/megaphone and the baffle.  At the two red arrows there were rings with holes as shown by the sketch.  These rings supported the baffle within the megaphone and let exhaust gasses flow through the fiberglass which was wrapped around the baffle.  These rings were also a good source of rattle.



In this next pic from right to left you will see the progressive mods I made.  First I removed the fiberglass and the central ring and drilled three holes in the end ring to lessen the back pressure and to increase the noise.  I then cut off the perimeter of the end ring to cut the rattle.  I was was not satisfied with the sound (too much popping) and figured it was the holes I had drilled.  So I capped the end with epoxy.  That cut the popping and I then tuned the baffle for sound and engine performance (while adjusting the carbs as well) by bending the louvers along the length of the baffle.



This last pic shows how I think the exhaust gasses flow.  Because the first set of louvers are angled away from the flow, some exhaust gasses go to the end of the baffle (flow #1), hit the end cap and bounce back colliding with other gasses (flow #2) and finally entering the interior of the baffle in two directions.  This bouncing around inside the megaphone maintains the deep throated sound while the multiple entry into the baffle keeps the overall noise level down.  When time permites I will shoot a video and post so that you can hear it.

[jonbuoy]

This is the muffler design that I have been using on every bike I have owned for the last 10 years. Nothing fancy about them really, just a simple race style design. Of course I use them on the street The outer canister and end caps are aluminum (or aluminium  ) and the inner pipe is a length of steel exhaust tube available from any auto parts store, with a few hunderd holes in it. Inlet is 2-1/4" and outlet is 2-1/2". Because of the large size and resulting low heat and pressure, regular house insulation works very well and lasts forever. Fully assembled weight is under 3 lbs. The result is a very deep tone at idle and the sound never "cracks" all the way through the rev range. Haven't had any problems with the police either as it's quieter than one might think. A piece of bent tubing can be made at any exhaust shop for proper fitment on the bike. I have actually used the high quality stainless flex tube in the past with good results.

Thanks for posting that,

[LoopsAndLogic]

Thanks indeed for those pictures

Can't wait to hear that bad boy. Still figuring where and how I will mount my under the bike exhaust system.

I'm still looking for a nice set of Mac or Kerker headers.
 
 Would any of you guys know where I could find those??

Thanks

[KB02]

If you're thkning about making your own pipe, I stopped by the auto parts store yesterday and was looking in the muffle section. They had a ton of pipe tips for these import/compacts, and at least four of the different ones on the wall would have been perfect for the outer shell of a muffler. All it would been would be a baffle, basically.

Just another option that we have.

Never worry about what it's supposed to do; worry about what it can do.