It is easy to check the armature with a multimeter, as there may be an open in one section. When a brush meets that spot on the commutator, the motor is disconnected, internally.
On a 4 cylinder Honda, the eBay replacement motor I purchased was garbage, except for the armature. That armature + rebuild kit + the old starter = a good working starter.
Thanks for that info. I'll do a little research on testing the armature and check it when I pull the brushes to see how bad they are.
For the comments about checking the electrical system on the bike. I have. Several times Grounds included. The starter is still bad when removed from the bike and hooked straight to a known good and tested battery with plenty capacity for this little starter motor.