Update
Well, I've got some good news, especially about the Kirby Classic III. I shouldn't have jumped to conclusions--the noise it was making wasn't bearing noise after all, but brush and belt issues! Just for the heck of it, I turned it on with the belt lifter in the "off" position, and NO NOISE!! Then I took the nozzle off, took the brushroll out and turning it by hand found out it was binding a little. I cleaned it up, gave the ends a shot of Liquid Wrench, and soon it was spinning freely. Then I put it back in and installed a new belt and now it runs the way it should--and is one of the QUIETEST Kirbys I've ever seen!!
Also have cleaned up and polished the 966 Electro-Hygiene tank and the 602 Royal. They both look much better. And I have a genuine Electro-Hygiene bag on the way for the 890, so I guess I better get that one polished up next!
Jeff