Originally Posted by jock
About that at the mid-point top and bottom
Should be close to OK....if you spin the rear wheel, does everything turn nice and easily? maybe slide the wheel a fraction forward and re-test.....see if it spins any easier, if not go back to your 1/2 inch play.
Fine line between beautifully performing track bike and one that will throw a chain in an emergency stop.....as I'm sure you're aware of now!!
This might help too...
http://www.63xc.com/gregg/gregchai.htm