When I was visiting Japan, I saw many Silver colored Honda CB750K2s at the used cycle lot, along with many advertised in their dedicated motorcycle magazines. I also saw the original 1972 brochure showing the silver colored CB750K2 but it's not listed in the American or European model. I wonder if anybody seen an original silver colored CB750K2 in the US? Since, I liked the looks, I decided to paint one of my own stock CB750K2 in silver. I also saw a CB750K2 in Planet Blue color in Europe. I learned that over there, they had large stock of CB750K2s so they didn't even introduce the new CB750K6 model until all the K2 were sold, so unlike us, they had no K3-K5 models.
I also saw several all-black CB550K in Japan. At first I thought this was custom painted until I saw the same all-black (with no stripes) CB550K on the Japanese domestic 1975 Honda catalog. I guess it's time to get a spare CB550K tank and sidecovers so I can make mine black, although I still prefer the early CB750 stripes I saw in the CB500 Four stunt bike disguised as CB750 in the 1971 movie "Stone Killer"