The number one thing to look at very close is the frame. Do not skimp in this area if the owner will let you strip the plastics off and check it good. Check the back bone under the gas tank they hide some scary stuff uner the tank. Also look real close at the swing arm for cracks they could be any place and look like a scratch. These are the two biggest things that I have seen over and over when checking them out. Plus I didnt do this on my mine when I bought her and got burned real bad. Wont be fooled again I know that for sure. Everyone that posted here also stated some other good things to look for as well. You may not catch everything but whatever you do DO NOT trust the seller look it over from top to bottom and then haggle the price based on what you find. Good Luck!!