Milt,
At zero sideslip the yawing moment due to asymmetric power is exactly balanced by the yawing moment due to rudder deflection.
This leaves the sideforce due to rudder deflection unbalanced until bank is applied.
The magic force is the same force which would normally cause the aircraft to turn once bank is applied except that in this (zero sideslip) case it simply balances the sideforce due to rudder deflection.
I am off to determine maximum bank angle for my Triumph Speed Triple and the variation of tyre sideslip angle with co-efficient of friction.
Cheers All