ID tank please.

[Snuffaluffagus]

Bought a tank at a salvage yard to replace the oddly shaped one on my 81 CB400t. It fits, its mounted, but I need a new fuel cap. Can anybody ID this tank? Thanks in advance...

 

[super8]

might be a nighthawk (cb650?)

 

[Snuffaluffagus]

Went through a whole bunch of pics on google and found out its a CB750C tank. I was looking at the wrong year bikes. Thought it was a mid 70s tank... Early 80s.