40K mi isn't terrible. More than most used sportbikes but not bad depending on the price, those miles can be a great bargaining tool for you to use to get some good money off. Hey anytime you buy used its a roll of the dice you never know 100% what your getting. All you can do it look it over best you can, get a good read of the previous owner, other than that it's all about how much your paying. Good luck!
4-Wheels Moves Your Body
2-Wheels Moves Your Soul
"To Much Horse-Power!" said no one, ever...