Exhaust: Anybody knows model/type??

Well I hope someone can identify it for you but it's likely not worth much except to someone trying to rebuild whatever model bike it is in the future once it's in vintage status. But good luck. The guys here are pretty good at this kind of stuff so give them some time.

can you find a serial number on it? that might help a little.

No inscription at all. Even under the chrome panels...

If it is real heavy it looks very similar to to the catalitic exhaust on my CB300 F with O2 sensor. The clamp to the down pipe looks the same. A lot of people dump them for louder lighter pipes.