You probably already did this, but ...... also make sure the other end of the negative cable, that attaches to the frame, is clean and tight. On my Heritage it was just forward of the battery, under the nose of the seat. The negative cable is only like 3-4" long

I had that bolt come loose once on my '03 Heritage and it caused all sorts of issues...

 

I've cleaned both ends of the negative cable, cleaned the ground on the regulator and am working on cleaning the ignition switch. Because the stoppage is intermittent, even after cleaning the ignition switch or installing a new ignition switch, the bike may operate normally. Anyway, thanks to all for your great suggestions. I've learned quite a bit about Harley maintenance and am enjoying, although at times a little frustrating, working on my Harley.

 

I've since replaced the ignition switch and so far, no issues. However, because the quitting was intermittent, I'm continuing to trouble shoot and will be checking the throttle position sensor, crankcase sensor, coil and plug wires. I also plan to clean the throttle body.

Again, thanks to all for your inputs. I'll close this thread and, with luck, won't have to reopen it again.