Sorry it took me so long to get back to this -- my persistent procrastination (and my new bike arrived

) so working on the Sporty has not been on the top of my list.
In the name of science, I decided to try the remedies listed here before getting radical with the darn thing:
- She's ridden it plenty, so I figure the vibrate it loose possiblilty was out.
- I used my engraver for a long time. Tried prying on it and broke the tip off my pocket knife in the process
. No luck. - I didn't have a good way to heat just the bolt head, and aluminum melts at such a low temp that I bagged the idea of hot/cold.
- I drilled a small hole next to the allen ball, and after a LOT of work was able to pry it loose.
I could not loosen the allen screw, nor could I loosen the other one, so I drilled the centers out. Unbelievable how frozen in place they were. I still had to drill the center of the remaining stud and use an ez-out to remove the threaded shaft. Thankfully, there was no damage to the primary cover or the inspection cover. Only problem was that there was a few days between starting and ending the project, and Mama decided to go for a ride

, but she quickly noticed the extra noise and the oil spraying out so she parked it.
Thanks to all of you that offered suggestions.
DISCLAIMER: There are no right answers. Seek them lovingly. (in honor of Rhino)