When I first looked at this Kenmore I could see it hadn't been oiled in like forever ......... at least many many years.
I oiled the motor while I was freeing up the main shaft and again after it was free. When the oil finally soaked into the bearings you could see, hear and feel the motor free up and run faster and easier. I oiled it a couple more times after it was freed up so I'm pretty sure it's good to go for a while now.
Joe