I'm sure I could think of some conspiracy theory about trying to get you to put more money into the slots or prevent bulimics from hacking up their lunch and then going to seconds like the Romans did, but I'm sure the answer is more simple.
IMO, it's probably because people who leave the buffet...
Just tell him to go the the DMV and get a new title before you buy the car. If he won't do this, don't buy it, plain and simple. You cannot register the car without the title, and he cannot legally sell it to you if the title is not in his name.
According to NADAguides.com, the value of that bike is between about $1,700 and $2,100. KBB is notoriously high in all their values, so I would not go by what they say.