rccardr = R/C Car Doctor. That's been my big-time hobby for the last 22 years. I race all over the US, mainly in the Tamiya TCS series. Wrote for RCCA for 7 years back in the 90's and that was the name of my monthly column.

The bearings fit into the sleeve that says Suntour on the inside and into the cups on the outside. As you mentioned earlier, it's adjustable- kinda like a Wood BB- from side to side because it uses two locking rings instead of a fixed cup. But it can only adjust maybe a couple of mm (and remember that wider on one side means closer to the frame on the other). With new bearings it will run much more smoothly. I've only ever seen one and it came in a prehistoric ST AA series frame, and the bearings were totally shot. After I replaced 'em it was like brand new.

That 87 SR2000 is my Grail Bike- the yellow one. Does yours have the handpainted stuff on it? Pretty sure it has a DA or period Shimano cup and cone BB.