I found my 1976 CB400F in 2020 in Rhode Island. I started working on it in 2022. I put in on the road last month! Eventually I will start working on some of the "oil tightness" issues. The one I bought new 49years ago, wept oil at the head gasket that first summer. So, I know it's part of the bike's character.
First picture is at purchase in 2020. Second picture is last month's FIRST RIDE. I will be asking fellow owners about the best way to replace the stock head gasket that guarantees a fix.