As with all used bikes, some have more issues than others.
2001 was the first year of a new engine design, so there were issues. If the previous owner(s), did there home work and put in the updated valve train,bearings etc, it should be a great bike. If I remember right there were also issues with the cases cracking at the swing arm pivot as well, but I am not sure.
Go to the nav bar<<<< and look in the "owners Doc!", there is a large quantity of info there.