Making Drag Pipes

[mluk1]

I've been looking around for drag pipes for my 1977 Cb750F, the only ones I could find are the MAC ones (which are too expensive and aren't positioned the way I like). I thought about just cutting the stock exhaust and running them like that, but after taking the pipes off the bike I notice that they're not lined up straight either. So now I think my only alternative is to make my own.

I want drag pipes that just come under the engine. My idea was to take the stock exhaust apart and trace the shape of the first exhaust on a piece of wood and cut out and template. I've seen people heat the pipe up and bend them to the template that way.

- What kind of metal/pipe would I use and where would I get it?
- Will the stock exhaust flanges and shims fit if I get pipes that are a bit bigger instead of having to weld a lip to the pipe?
- Someone told me to pack sand into the pipes to prevent the it from crinkling?
- I'm going to heat wrap these, but do I still have to coat them with anything?
- Would anyone have any links or references to do this?

[Re-run]

Well if you are going to wrap the pipes, then coating would not be needed. You could also probably just use regular exhaust pipe.
However, the lip is used to mount the pipes, the collets go around the pipe and apply pressure to that lip to seal the exhaust. So some sort of lip is needed otherwise you would have to weld a bracket onto each pipe to allow the pipes to seal to the engine.
Unfortunately I dont know anything past that as I have never made any pipes.