This time of year I'd try to get a deal both are happy with. Ask him to prove it runs. He can't so go from there. Have cash in hand of the amount you HONESTLY think it's worth. Then point out all your expenses it will take to get it running. Depending on how long it's been on Craigslist you can deduct even more. I despise lowball types but he may think that's exactly what you are doing unfortunately. But you have nothing to lose by trying except your time. If you are correct in that type of bike is hard to come by, then you don't want to go too low. Take what his asking and start deducting. There's a price there somewhere you both will agree on. Go for it.