Yeah those look pretty bad. Still, it's such an overbuilt unit if you replaced all the ORinigs, I'd wager that it would still pump up to 60+ and trigger the safety valve.
Still, you'd like to get a better one, understood.
When I did mine, I hovered on eBay till I found one with 7500 miles on it, from a 75F, guaranteed by seller. Paid $75 for it. It looked pristine, rotors nary a scratch. Took about three weeks of shopping, logging in to eBay twice a day etc. So much stuff is "buy it now" rather than an auction, you've got to be ready to buy, or someone else will get it.
Bot several to get to that point, mostly in the $30 range from K2 to K5. These are mostly pretty beat up too, though not as bad as yours. But that range bike got the most mileage. Fs, 77s and 78s are usually low mileage, loss of interest plays. I'll resell the ones I don't want. I think you can find better than mine.
They are out there good luck!
