if you buy a used bike with just a bill of sale is it possible to get it registered in your name?
It depends on the age of the bike and the state you are buying it from.
Most states require a title now and if the bike/quad comes from one of those states and is fairly new (in fl it is any bike 2002 on, I THINK ohio is like 98 on or something like that etc., etc.) then a bill of sale only, is no good, you must have the title and any lien releases (if applicable).
What state is it coming from? and what year is it?