This process does not require specialist gear pullers or other tools

Warm the gear to at least 30 degrees centigrade which will allow the plastic to stretch over the motor shaft without splitting. Simply holding the gear in a warm, closed hand for a few minutes will be sufficient or soak the gear in a container of warm water for a few minutes.

Place the gear on a hard surface with the circular flange facing upwards.

Gently push the motor shaft into the hole in the centre of the motor pinion gear. Use a constant gentle downward pressure.

Continue until the motor shaft is right through the gear and touching the hard surface.

Position the motor shaft over a void or hole in the hard surface. In this picture a gap in the jaws of the pliers is used.

Again apply constant and gentle downward pressure to push the gear along the motor shaft and into the correct final position.

Here the motor pinion gear can be seen in the correct final location along the motor shaft.

The exact location may depend on your specific application.

Note:

This pinion gear is used to service several different types of motor pinion gears fitted to several different Scalextric motors used over the years (decades). With some motors, especially those with poor or missing spines it may be necessary to reduce the diameter of the internal hole of the pinion gear. This will ensure the pinion gear is a good tight fit onto the motor shaft.

To do this, use an opened up paper clip to smear a little superglue on the inside of the pinion gear. Allow the superglue 1 hour to set fully before a trail fitting the pinion gear to the the motor shaft. What you want is a good tight fit where the pinion gear will slide onto the motor shaft with a some effort. Add another smear of superglue onto the inside of the pinion gear if necessary. Allow this to dry fully for 1 hour before trail fitting again. Repeat as required.