exhaust mod

I

imirish81

New Member
I had a some issues with my exhaust set up. I could not get the exhaust to clear the frame of the bike. I tried all the trick and eventually bent the exhaust pipe and was left with a not so sightly exhaust pipe. In an attempt to make lemons into lemonade i came up with this mod. I hope it can keep a few exhaust pipes out of the landfill.

For the mod you will need:

1/2 inch compression to thread EMT fitting (at least two) pack of 6 is about 2 dollars
1/2 inch pre bent EMT (one) about 3 dollars
something to cut the exhaust pipe and EMT
half inch pipe thread tap (probably the most difficult to procure)

OPTIONAL
although i didn't use it a sealing compound would be helpful to prevent leaks.

The compression fitting disassembled
DSC00602.jpg


The flange is threaded. the compression fitting is shortened so it does not extend past the flange.
DSC00597.jpg


The muffler is threaded
DSC00598.jpg


finished product. strap can be affixed.
DSC00596.jpg


The whole setup can be adjusted with an open ended wrench in minutes. The freedom of motion is much greater than any other set i have seen.
 
I like your idea. I'm currently planning the exhaust for my second build and have actually toyed with the idea of using electrical fittings and conduit (emt) for the pipe. I'm curious how much leakage you're getting at the compression fitting. If it is excessive you might try a high temp silicone gasket sealer made for exhaust manifiolds. Coat the compression ring and the threads; Might take care of it. My concern is how vibration will effect the life of the threaded compression fitting.
I want to extend the pipe to the rear and have the muffler near the sprocket. I've bent enough pipe in my time that I'm confident I can get what I want. I was considering welded joints but the versatility of the threads is interesting. Thanks for the idea.
Tom
 
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I'm not getting much leakage. I will probably try sealing it with something. High temp silicone sounds like a great idea. I want to retain the ability of disassembling it and silicon would make that possible. Silicon will also give it some added strength. The compression fitting is pretty solid, i don't think it will fail under vibration.

I was originally going to extend the EMT to the tire as you suggested but opted to leave it short. My reasons being, i did not want to restrict the exhaust, any moisture or oil will lay flat in the exhaust system, the exhaust is not directed straight down and instead towards the back spokes, and its a ***** to bend EMT. You could increase the EMT from1/2 inch to 3/4 inch and reduce the back pressure if you could find a reduced compression fitting.
 
tyrslider said:
Keep us posted! It's a pretty tidy mod. Can you get'em in other materials (stainless, brass, etc)?
Click to expand...
I've never seen electrical fittings in anything except galvanized. They do make explosion proof fittings for hazarous atmospheres in stainless steel but they are typically bulky and ugly fittings. The standard stuff is okay for our purposes and can be coated with high temp coatings that looks close to chrome, and other colors. I'm waiting to see if engine vibrations have any adverse effect on the threaded couplings. They do make 1/2 to 3/4" couplings but if I were going to go with 3/4" I'd start at the cylinder and carry it through to the muffler at the rear.
Tom
 
Ive ran a 1/4 tank through the motor and so far no movement in the fitting or odd rattles. I haven't even added a strap yet, which is a big no no. I'm going to pick up a tube of high temp silicon and try that on the fitting to reduce leaks. Ill keep everyone posted.

"They do make 1/2 to 3/4" couplings but if I were going to go with 3/4" I'd start at the cylinder and carry it through to the muffler at the rear."

To do what you suggest would involve some work on the exhaust port and use of a different muffler. If you have the "skillz" and wouldn't mind possibly ruining yr motor it would be a project worth doing.
 
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