Long ago I made a promise to communicate this forum if my CB500 crankcase had developped any damage caused by the O-ring I had in the 80s. It was an EK (Enuma) chain, with quite a wide clip link I remember. Although I had my sprocket cover removed a couple of years ago, I forgot to look. Sorry for that.
Yesterday I had a look and took pics. Well, the CB5
50 may be another thing, but as far as the CB500... frankly, I see no objection why an O-ring chain wouldn't fit. I looked closely, but I could not detect any sign of damage.
I wasn't impressed by that chain for another reason and ever since I have used the open chains again. I should also say that I personally prefer clip links over stake links any time.
A workshop specialised in SOHC
Fours 25km from here, mounts O-chains on CB500s regularly and also sees no objection. This is the type he stocks:
https://www.fourdeelshop.nl/cb500/aandrijving-2Make no mistake, I'm not recommending O-ring chains, but if you
really want one, I see no objection, not as far as the CB500.