By the time you fix that you could have bought a decent one......stock.....and probably still end up ahead. Too many people are down on their luck these days for you to not find a better deal. Keep lookin'
From the looks of it I would question the integrity of the frame, it looks like the rear set is hanging off, I wonder if it broke off and what that did to the mounting points. And that is only from a quick glance at the pics.
Well if it's not stolen and you can get it as a track bike for 1500 I would jump on it. New parts for R1's are really inexpensive compared to other makes. I would make sure the forks are straight and inspect the frame but I would say you could easily have it track ready for 2500-3000 including purchase price.
I raced R1's and they are very good on the track. A full system kills the weak midrange and like I said replacement parts are cheap.