R12 or R5 Exhaust measurements please?

[jjwithers]

I have a random request...
Maybe somebody here owns one of these bikes.

Does anybody know the size of a R12 or a R5 exhaust (muffler) pipe?
An R67 might help too...

I'm curious as to the length of the pipe from front to tail,
the height of the pipe towards the middle of it.
and the pipe's opening at the front of the pipe...

If anybody happens to have a muffler, or one attached to a bike, please shout. thanks!

-josh