Buying a bike without a title?

in about a week and a half i am supposed to look (and probably buy) a 2000 Yamaha blaster from on of my best friends. the only problem is it doesn't come with a title only a Bill of Sale. the bike isn't under his name. how can i just check to make sure that it isn't stolen or have a lien on it. and then how would i get a title for it in my name. i have been looking on the internet for days but i haven't found anything that is relevant to my situation. thanks -Matt