Motorcycle generators are weird. Instead of regulating the field current in an alternator, they just spin a permanent magnet in a stator. This is heritage from the days of magnetos. Anyway, the voltage is a strong function of engine speed, unless the coils are shorted, in which case the current rises to cancel the field of the permanent magnet. The voltage regulator lets the voltage rise to ~14.5v and then shorts the coils shunting away any excess generation. This causes large currents at zero volts, unless... the connectors get corroded or dirty and have appreciable resistance. Rain water getting into the connectors causes them to overheat, melt the connector, and fry the wiring. This is why Bumblebee isn't charging properly. If the wires could be cleaned and we had a good soldering iron, we could just replace the connector with soldered connections.
Later we would find out the stator coils were also damaged, so new voltage regulator, and new stator before reliable charging was restored. Poor 17 year old Bumblebee.
