Motor Wheel Assembly
Now it's time to put the motor and wheel together. We'll need the motor assembly, geared wheel and track assembly.
If we look at the center of the geared wheel there's a recessed hexagon shaped cavity. This allows the pin to snap onto the wheel. The top of the pin features a hexagonal shape that keys into the wheel. This ideally should have a tight fit and could be used "as it" but we'll use a screw and threaded insert to secure these piece together. It'll help ensure the wheel doesn't pop off while in motion!
Place the motor housing onto the motor track. The pin from the motor should pass through the slot. If it doesn't, turnover the motor housing until it fits. The pin should protrude through the base. Place the geared wheel over the pin and rotate until the registration lines up with the key on the pin. Press them together to install the wheel to the pin.
Check the placement of the wheel and ensure it's on straight and level with the track. Rotate the wheel if needed. The thin circles on the wheel should just barely touch the base. Insert a short M3 x 6mm screw through the wheel and drive it through the threaded insert in the pin.
With the wheel now secured to the pin, you should be able to test out the mechanism. Start by moving the motor all the way to the left and rotating the gear counter-clockwise until it stops on the first tooth of the lower track. Then, rotate the wheel clockwise until the teeth engage the lower track. If you gently push the motor along the track, back and forth steadily, the gear should rotate following the tracks.