I did an oil change and dropped the oil pan to install a new seal. It seems to have worked; the bike is still leaking a very small amount of oil but I think it's coming from the countershaft seal or the shifter seal. I suppose I'll have to dig into that, but not until it becomes obnoxious.
Changed the air cleaner too.
Today, though, was a banner day for me... as of this morning, I have ridden my CB650 twice as far as all previous owners.
Here's the original odometer mileage when I brought it home back in April of 2016:
