Ok, the verdict. The hocky pucks on the CB550 frame are 1/2 an inch wider than the CB450's. With a little work the tanks(CR450 and Manx) will fit on the CB550. I can almost guarantee that these will fit the CB500 four also with some work. Keep in mind that most of these tanks were designed to be somewhat of a universal fit, rockcity can probably back me up on this one, but most of the tanks can be fitted to almost any bike with a little work. If the tank just absolutely won't fit then I'd be happy to give you a full refund or if you are dead set on getting that style of tank to fit then I will do some prototype work and get it to fit for you.