Mainly service history ... as if none you could be buying a lemon with alot of money to spend on it . I service customers bike with 115,000ks on them & they still do over 240ks but I keep them well tuned & looked after .... Headset bearings / front & rear disc's , chain spockets etc should be checked as if original they will be be needing replacing , if not already done . Take for a ride & check for any transmission vibrations & clutch slipage ... Take a side pannel off & see the condition of the engine this will give you some idea if being serviced & looked after , Most motors if had their shims checked will have the front gaskets leaking slightly not a biggy to sort most do this ... Ask if it has had any charging trouble & if so has the Reg/Rec had the wiring modified to correct this ...