Always use an OEM Kenmore branded Style Q synthetic microfiber dust bag and change the CF-1 pre-motor filter every six bags. I have this same model and it runs strong.
Job well done. I like the simplicity of those machines but I find them less robust than the older models (pre made in hungary) ones. I also find the rewind button to be weak.
I can tell you right now if I had to send you my power mate for my Kenmore and I bought a new belt and it would come on and shut off i can't remember if was you i talked to before and I think there was other things going on and I found my book or manual and I have all info on it even the box it came in hope to hear back from you.
There isn't a lot available at that price point that is bagged. Probably the best bagged option at that price point is the Hoover Complete Performance. Home Depot currently has them for $189 and in that price point I think that would like be your best option. Hope that helps!
I'm actually a bit concerned for the motor. That was a ridiculously dirty pre motor filter. With that being said, I'm not a professional like you are so you probably know it better than I do.
You're right to be concerned, it certainly wasn't good for it to run that hot for long. How long they took off the life of the motor is hard to guess, but it is running well now... we'll just have to see if issues crop up a couple year's down the road.