I have Gixxer 750 rearsets & master cylinders ready to go on my cb750f with small exhaust clamps.
Since my bike is an F-model and has rear discs it will be an easy bolt on. (too lazy to do...)
However, since your cb550 has a drum rear set up, have you figured out how you are gonna make the rearset work with the back drum?.. I think that would be you bigger problem to solve rather than frame/exhaust clamps...(Hell you could even just bolt it on to the rear passenger peg if you want...
The Gixxer left side is designed to work with a MC and therefore the brake lever creates a has a verticle motion, (to push the MC plunger), rather than a horizontal (pull), motion that you need to horizontally pull the brake rod..
Im curious to know how this can be solved, since I want the option to put my Gixxer the rearsets on to either my cb750f or my cb550f...