Originally Posted by .crispy

Depends on how big the pinion is for starters. Sometimes I unmount the motor, make sure the shaft is through the hole and angle it. I get the pinion on and lined up with the flat part of the shaft and tighten it so that it stays on.

Then I mount the motor and then go from the bottom to position the pinion so that it lines up with the spur.

The entire process is easier the smaller the pinion is.