raw motorbike easy auto chain tentioner and expansion chamber exhaust

[Ghost0]

We have used copper fittings on our expansion chambers for well over a year and they hold up just fine. Solder on the other hand will not. Typical 2 stroke exhaust temp is around 800 degrees F. Melting point of copper is around 1300 degrees F. We use silicone tubing to keep the joints of the copper fitting from leaking.

On another note, I would recommend replacing that 90 degree fitting with two 45 degree fittings. 90 degrees is just too tight of a bend. I think you will see a performance increase. Also it appears your header length is a little short. 12 inches from the exhaust port to the start of the expansion chamber is a good start. I think adding the two 45's will get you closer.

 

[MikeJ]

I agree, copper joint pieces do make for a nice exhaust appearance. Silver solder *might* work for low temperature operations. Its melting point is above 800 degrees F, but that depends upon the alloy combination of the solder.

But another thing to remember: Copper becomes brittle with exposure to vibration. These engines vibrate a lot! If the silver solder holds, at least one copper piece will develop a crack as the exhaust system flexes. The crack will eventually break completely apart in time. You will no longer have an effective muffler system. (Other than compliance with federal laws, that could be why auto and truck exhaust systems are not make of copper.)

I have read of some guys using flexible gas furnace line, flexible steel exhaust tube for motorcycles, as well as electrical conduit. Have not heard of anyone using galvanized threaded water pipe. That would work, but it would be a bit heavy. (I use galvanized water pipe on my 4 horsepower lawnmower to redirect the exhaust. The pipe and joints went into place over 10 years ago and it still works. After the zinc coating burns off, the pipe assumes a battleship grey color. And it rusts when it gets wet. Maybe high temp exhaust paint from a NAPA auto parts store will help there. )

Keep tinkering! Let us know what you decide upon.

MikeJ

 

[joey d]

where do I get this high temp silicone tubing that doesn't melt? what is it called? and can I run it like piping from the header to the chamber.

 

[skypiratescotty]

I got the expansion chamber from SBP and used muffler repair tape from Auot Zone to wrap the copper fittings. If I remember right it was around $7 and easy to use. After install a quick ten minute ride and the tape sorta melts together and seals it up. Have at least 100 miles on it with no problems.

 

[Ghost0]

You can get the silicone tubing here.
http://www.sickbikeparts.com/catalo...id=87&osCsid=320f90d2b6921507b47f9b90f40427d7

 

[joey d]

thanks guys I have a lot of options to think about now. I think I am gonna try some stainless steel flexible exhaust tubing. It would give me less restriction then all these copper angles and allow me to play around with tuning length.

 

[Ghost0]

Give it a shot but in my experience the corrugation in that tubing does nasty things to exhaust flow and the pressure waves.

 

[joey d]

didn't think of that am`I able to go from the header to the expansion chamber with say 8 inches of the silicone hose. or do I just use it for the pipe connections. Also am I ok with heat wrapping around this hose to hide it. or would this keep in to much heat and melt the tubing.

 

[joey d]

I meant to say is it safe to use this hose as an actual exhaust pipe or just to seal the connections of the exhaust pipe. also is it safe to heat wrap it. any one know the melting temp.

 

[Ghost0]

The silicone is good but won't last long directly exposed to the exhaust gases which is why we only us it to seal the joints and not as the pipe itself.

I would think wrapping it would increase the heat is sees and will probably deteriorate it prematurely.

I would just use two 45's in place of the 90 and then either just wrap it and hope the wrap itself helps reduce the leaks or use the silicone at each joint.