Did you check the 55A fusible link first? If that’s blown you have no alternator.
I'll check it but the bike is starting and running fine, would it do so if that fuse was blown?
I know that the Battery Bug says around 13v when starting (I keep the batteries on a smart trickle pulse charger) but after I start the bike the Battery Bug shows 0% charging and the voltage starts dropping. It usually shows 14.2 - 14.4 when running.