If the price is right, you could really be getting a good deal. Voice your concerns to the seller (tacfully), see if he has any kind of maintenance history on it, or receipts for any work done on it. I realize it's "let the buyer beware", but you can still be an educated buyer. He seemed willing to answer the questions posted to him on ebay so you might be able to get a feel for how confident he is of the overall mechanical condition of it.
Hey, and the rest of the guys are right, if you absolutely, 100% knew what you were getting into, it wouldn't be as much fun would it!?!