Kittys,
Well, I would not have taken the motor completely apart, but since you did, I'm gonna suggest a couple things.
First: Make sure it's back together so the armature shaft does not bind. It should turn effortlessly.
Second: Make sure all the wiring is properly connected. A bad connection will reduce the current the motor is getting and can get hot.
Third: Make double sure the bearings are greased. Getting too hot after 10 minutes sounds like a lube problem to me.
Fourth: If none of this helps, you might have to take it back apart and start over. If all is well it should stop smoking.
Joe