how do you know if a atv is stolen?
Just because he doesnt have papers doesnt meen its stolen. I bought a 400ex that the guy didnt have any papers for, but I knew the original owner that he bought it from, and everything was on the up and up.
Also, price just depends on the demand.....if the market is flooded with similar machines, then you will have a hard time selling unless you really drop the price. The guy may be in a tight spot too (divorce, lost job, etc.), so he needs to get rid of some toys to pay some bills, thats how I got my 400ex. Situations like divorce can make it hard to keep track of all of the paperwork.
Like everybody else has said, take the vin# and have an officer run it for you. If there are no vin#'s left on the machine (filed or grinded off) then you can pretty much bet on it being stolen.