Like Hill #42 said.
With the clutch cable disconnected you should still be able to rock the bike back and forth and get her to shift through the gears. Don't hammer on the shifter. A little tug in either direction will get it to shift as the gears move.
There should be at least about the thickness of a nickle slack between the lever and the perch when you start to feel the slack taken out of the cable and disengage the clutch.
.
If that doesn't help...start working backwards... through clutch, and unfortunately back through to the tranny.
Tuck\o/