The CL450 tank fits on a CB750, slides right into the front rubber mounts and is the same length as the stock tank, due to an extension which is hidden under the CL450 seat, but exposed on the CB750. It is not unsightly, barely noticable, probably less so on a 550. The Union tube spigots near the tail foul the frame rails, but a good machinist/welder could modify that in a twinkling. They may not foul the rails on the 550, being slightly smaller. It is s short 2.5 gallons, and I think a good looking tank.
I hope to use one on a CB750 project.
http://en.wikipedia.org/wiki/Honda_CL450Click the photo to enlarge it.
