Quote:

with the motor running the battery's reading just under 15 volts



Are you reading that voltage directly at the battery terminals? +15V sounds high to me. Just to be sure your system isn't overcharging, you should measure your other bike with the same meter and compare the numbers.

Jack

'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy