Not knowing much about a CB77, I did not realize the ring around the top of the gauge where the rubber cushion sits (also where the screw holes are for holding the gauge in the headlight case) was not actually part of the gauge. It slides off and the rubber ring goes with it. Well, not easily when it apparently hadn't been removed from the other gauge
maybe ever. The rubber was stuck to the bottom of the crimp ring and I literally had to use a razor knife to cut it loose. A little risky and tricky, but I got it done and transferred the ring with rubber attached. Only thing I didn't consider during all this today was that the oval metal ring slides on the gauge, so even though the screws are in place the gauge can still shift around a little. I'll worry about that later if it's an issue. But I took the bike around the neighborhood a bit after wrapping things up and the tach and speedo seem fine, and it's nice to have a speedo that works again.
I swapped over the blue jewel for the neutral light as well, along with the OEM rubber socket and Stanley plastic nut for the jewel. I initially thought I'd make the red indicator in the gauge the neutral light and the blue jewel for high beam, but ran into a roadblock because the high beam socket only has a positive wire and the body of the gauge has to be grounded for the 2 illumination sockets to get ground as well. Interestingly, when I tested the gauge on the bench it worked smoothly with my drill on high speed (42 mph and about 10,000 rpm) but the ride around the neighborhood showed both needles wavered just slightly. So I pulled the tach and speedo inner cables and lubed them up with the marvelous Kable-Ease to see if it helps. After all, the cables are as old as the build and have never previously been lubed.
Happy with how things turned out, looking forward to a short ride before we head out next Tuesday.