HI, I recently sold my Silver Star and I'm now selling a couple of cams that I bought when I was planning to improve the engine performance - (I never fitted the cams; sold the bike as 'standard').
I have two adverts on Facebook 'Marketplace', one titled ROTAX 665 cam, the other ROTAX 667 cam.
According to Sportax, either of these cams will make an improvement over the stock 660 cam (and the cam swap is very simple).
Mike