I managed to loose one of my original keys to the ’74 CB550 recently, but fortunately, a local locksmith had blanks and was able to cut me two new keys from my remaining original.
I also broke down and installed new spark plugs. The bike was still starting and running good, but it would miss if you really wound it up to 8000 rpm. It’s not like I run it revved this high as it will cruse along at 75 mph turning just under 7000. It was time for new plugs…..