Hi Janey - I appreciate your insight into the rotary tire issue. I don't know why my White Rotary 43 has a larger diameter (and slightly coned) pulley vs. my White series 77. They definitely both looked old...and had been used...but I'm glad you think they might use the same one. I believe that Suni found information indicating that the same friction pulley can be used for both models.
As for the flat tire spots, I'm using a wooden dowel to keep the pulley from resting on the motor. I've also heard that bubble wrap works well!
I ran into another issue today on my 43. I pulled the motor brushings (those big black screws on the motor) and there were no brushes attached to the springs! Just the springs. I looked into the motor holes from where the springs were pulled, and it looked like threads on the side (of course) and silver metal at the bottom. I'm now trying to figure out if the rotary motor on the 43 didn't have brushes to push against the motor commutator. ?
Thank you again for your compelling comments and questions - I appreciate insight from experts who have done this before!
-Cyndi J