... Does the bean can 'advance and retard' the ignition timing??
Yes, it does. Loosen the two Allen screws just a tad and then use a flat-blade screwdriver to pry the bean can -when facing the can- counterclockwise to advance and clockwise to retard the timing.
Of course, you'll need to have a timing light prepped and watch the flywheel timing marks.
Please consider adding your R65's model year to your sig line. I know differences in model years can mean differences in answers, as in correct or not.
BTW, I would not jump on altering ignition timing until I had confirmed a good battery, proper choke operation, checked for water in the float bowls, correct valve lash, blah, blah, blah. The Airhead will start and run pretty well even with the timing several degrees off.