The first thing to do is pull the Ultra Dash motor apart. Just use a small flat blade screw driver to pry open the metal tabs on each side of the motor can. Once you've done this just pull the armature out. See below.
The next thing you want to do is to move the small plastic washers on the shaft from one side to the other.
So remove them from the side with the commutator, see below.
And place the two plastic washers on the OTHER SIDE of the motor shaft, see below.
Push them all the way up until they hit the steel stop on the shaft.
The reason we do this is to allow brushes to sit more centered on the commutator. I found in my testing that in stock form the brushes sit at the edge of the commutator, loosing some opportunity to pass more current through to the motor. Changing the location of the plastic washers allows the brushes to get better contact with the commutator.