I've got an old BSA tank, not sure what its from but its not from a B33! Its going to be though, so I needed to add brackets and tabs to mount it to my frame.
First order of business was to remove the extra bits and make a rear mount, and "ears" for the front to bolt up to the mounting hole in the frame.
When all was said and done, it came out good. The tank sits nicely and is secure. I used rubber bushings so it will be at least a little isolated from vibration. There are a couple pinholes in the seams that need attention, but we're looking good.