If you heat the inside and quit as soon as it loosens it won't normally put much heat into the windings.
But most of the time when I do that the windings are either already gone or going to be stripped for rewinding.
You're a lucky guy if you have a lathe to use.
Do you have the newer motors with the 9mm bearing tubes? On those I think you could move the shoulder on the 9mm portion a little closer to the motor to take a little bit off of the height. I only have the original version moto with the 8mm tube. You can see them both here: