Just a guess and maybe something you should try.
The power cuts out if the brakes are applied. It is one of those circuits where if the brakes are disconnected, the bike will still move so you are not stuck somewhere. An open switch will let the motor run. A closed switch will inhibit the motor. Also, if the headlight or taillight is connected badly, wrong, or corroded or something, the bike won't work.
Therefore, if you electrically disconnect the brakes and headlights and tail lights, things may work. Keep track of the connections so you know how to plug it in again.
I am no expert and I don't own your bike, it is just a thought, do at your own risk.