I'm having problems tightening the chain on my MC28, hoping someone here can help.

Here's the deal:
I just put a new chain on my NSR, which has been apart for about two years. Turned the adjustment ring counter clockwise at first and it moved a little, but in the wrong direction. So I went to turn it clockwise and it will not turn. Now it will not move in either direction. At the moment the chain seems to be adjusted all the way towards the loose end.

Does some thing lock out when loosed all the way? Or could something have happened to the hub? Or am I being a bone head?