usually there is an adjuster down by the case as well, might help to download the service manual i'm sure it's online somewhere.
I highly doubt a 250 ninja would burn through its clutch plates in 3100 miles... it seems highly unlikely to me.
seriously try adjusting it, see if you can turn things in such a way as to give your cable more 'slack' therefore not pulling on the clutch right away. You can always turn it back to where it is now.