How longs a piece of string.
Has it had regular oil changes/service.
Is there a known problem with the model eg:Old single overhead cam honda's had oil feed issue to cyclinderhead.
Sports bikes are more likely to have been thrashed than tourers.
Then again some bikes so fast unlikely to have been ridden flatout.
If the milage very high what else needs replacing, brake's, suspension, exaust etc very expensive.
Have'nt got all day to list the problems you may get with high milage machine, but will say that the difference in price bettween a lower milage bike, and the one your considering, probably wont be as much as you could end up spending sorting out the high milage machine.
I personaly would'nt touch anything with over 50k on it unless it was given to me, and even then I may walk away.
So how high the milage and what is it?