I have an Eahora x7 with a 48 volt 750 watt motor on it and its failing. i want to replace it but the manufacturer has told me they have no stock left and i would have to order from china and it would take 2 months by sea to get it. Can i just buy another hub motor with same specs and use it? or does it have to match the battery and controller on bike? they want 420 plus tax and shipping for new motor and wheel assembly.