From Unofficial Zero Manual
Motor alignment refers to physical alignment of the motor with the frame and swingarm so that power is transmitted correctly to the final drive.
- The back side of the motor (encoder side) has screw jack bolts that let you tweak the motor position.
- Mostly this is only needed when (re)installing the motor.
- Loosen the four M6 socket head screws.
- Adjust the portion of the silver nut that is not wedged into the slot on the motor.