On my 250 I got one that "needed the carb cleaned" turned out that the wrist pin came loose and messed up the cylinder as well as the crank bearings having play, just to get the crank rebuilt and new inserts in the cases I'm looking at $900.00 just for the bottom end. And that's with me taking it apart and putting it back together.

My mistake was being too much excited about it and not giving it the FULL look over. Ive always liked if the seller is specifically avoiding a topic to make sure to check it out. Always inspect the frame closely, and make sure to pull up on the frame to check the wear and tear on shocks and shock bearings as well as steering. Give everything a good wiggle to make sure its tight and not neglected. Good luck on the buy