When I put the rear tire in the air and test throttle the motor shaft turns. It spins up to full speed. Its only the smaller gear on the motor shaft that sits still, which in turn does not spin the motor chain. If I spin the smaller motor shaft gear by hand the chain spins just fine. Rolling the bike backwards gives me resistance and spins both the smaller motor gear and chain like it should. I really need this fixed today.

Also when i try to move the gear on the motor shaft as if I'm trying to take it off the motor rod it won't budge. Because of this, I believe that the key is still there. When I look in the smaller gear's slot there is a piece there which I think is the key