Spindle is toast IMHO. Lack of maintenance can ruin rotating parts, despite light use. Example, you rode it a few times yourself without checking those parts first. Pretty safe to assume former owner did the same thing.
I would much rather buy a bike with high mileage that has been ridden regularly, than one with very low miles but has been sitting, neglected, for years/decades.
I would not put additional time into cleaning cups.
I have yet to have gotten a 20+ year old bike where the bottom bracket and wheel hubs did not require service. While you probably did not damage them, occasional use with neglect of any maintenance by the PO most likely did.
If you have not taken apart the HS or wheel hubs, I would give both high priority.
Water intrusion can turn grease into mud. I've seen it a lot.
A new cartridge Shimano UN26 BB costs all of $10 on line. Include with other items from a supplier like Jensen USA, and if you order at least $50, shipping is free. Once installed, its hard to see that the bb is not the original, without a very close inspection.
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Please don't confuse ebay "asking" prices with "selling" prices. Many sellers never get their ask price. some are far from it. Value is determined once an item actually SELLS. Its easy enough to check SOLD prices.
Last edited by wrk101; 09-20-12 at 01:22 PM.