I have done that size and larger to pull apart when I've repaired these gennies before and yes they can be fun, first I just take both end caps off secure the body of the unit and give the rotor a decent pull. Sometimes it works sometimes it doesn't so by doing it vertically using a chain block it's an easy job to get them out.
Now to get the rotor back in place vertically is the way to go as when it wants to hit home the body of the unit will jump up and sit home, then place the end caps back on and set it up.