I was riding my cube electric mtb when i fell off riding through a ford i picked the bike up straight away and the motor didnt seem to be working.My gears had gone to pot with the chain going over the big cog when shifting.so i put the chain back on and just used the others at this point the motor worked and got me several miles home now when ive gone to adjust my gears at home the motor is not kicking in again i dont know what to do.I have a cube performance motor.can anyone offer any advice.