Header interchangeability?

[CDG306]

I have an 81 GS650 and am planning an exhaust for it. Does anyone know if any of the other models share exhaust port measurements? I am wanting to start with a used header of some sort and the rest will be custom. I just don't know if anything else would bolt up.

[Crankthat]

I cannot say as I am not familiar with the measurements on the 650.
May help if you measured yours and posted.
Here is what I have sitting around unattached to anything.
Pipe OD where fits in header in IN measurement.
81 550L 1.5
81 750L and 1100E 1.75
79 CB 650 1.625
84 Nighthawk 550 1.655
XJ 600 (seca II) models 1.55

Important to note that the XJ 600 will have restricted flow due to the actual pipe od.
There is a difference in bend on the Suzuki L and E models.
Though the 550 and 650 frames are much the same the 750 and up are different so the bend on the headers may be different also.
The 750l and 1100E measurements both are from 16 valve motors and I do not know if the 8 valve motors or different years would be the same.
There are videos on youtube showing best ways to bend a pipe and you should learn all you can about that if you are not experienced in that already.

P.S. As payment for this info I expect you to walk the next old lady you see across the street as it is friggin cold out in the barn where I have my exhausts hanging!!

[CDG306]

I really appreciate that! I will try to get mine pulled apart to get a measurement. I am thinking the 550 may be the only one close enough to work. It's cold here too and I need to wheel the bike from the shed to the garage where I can do some tear down.