Bikes with leins are sold all the time, as are cars. It's really not a big deal and banks are used to dealing with these situations all the time. Of course if the guy can get the cash to pay it off first, that's a big help. 1k down is a little steep, but if you decide to buy another bike, realize that you shouldnt buy the bike, or change your mind for any other reason, he now owes somebody a lot of money until he sells the bike.
to what Ralph said basically... and hey, my 01 zx6r is for sale and I *DO* have title in hand.