I'm certainly old enough to know I shouldn't trust the "little old Lady" story from a used car dealer, but I totally got suckered in. "It was running great when we parked it last fall" turned into one corroded piston that was full of penetrating oil (like they tried to soak it to get it loose), which we solved, getting everything apart and cleaned, but now I see that to ad insult to injury, trying to force the seized piston, they cranked on the 19mm bolt on the signal generator, and sheared the connection to the crankshaft. Behind the signal generator--the bit with the 19mm bolt--I just see a bunch of galled metal.

Has anyone ever dealt with this issue? Any help would be greatly appreciated!

So it looks like I may have found the solution already here in the forum under the topic " GS500 Crankshaft -> ignition unit location pin" It does seem like the pin has sheared, and I can see the remnants of a hole, so I will try re-drilling the hole and seeing if that works.

Thanks to everyone who has contributed to this forum, and if anyone has any more advice on this situation it would be very appreciated!

"little old Lady" eh...........Hell's grannies.
https://www.youtube.com/watch?v=CStfT8gCrjM