[...] Just to add to the mix I have a 500 Honda owners handbook marked K2 that has a 550 clutch shown. It's not the for the later (4000) Euro 500s as it shows original 4 in line idiot lights etc. Probably a very limited no.
I know what Owner's Manual you are referring to. It has two odd errors. The clutch shown in p. 72 was
not on any CB500K2 and neither was the blow-by breather element shown on p. 66. Very strange. Probably due to copy and paste from a CB5
50K2 Owner's Manual.
http://www.honda4fun.com/pdf_libretti/500/CB500_75/libretto500_2.pdf