The actuator shaft has to be pre-loaded approximately 1/4 turn from the relaxed position. There is an internal spring and that has to have tension on it.
I'm going to surmise that you took the actuator arm off the actuator shaft in your zealous approach to removing the cable.....
In the future, don't take it off. It's like a mousetrap.
Here's what you do. Take the actuator arm off the shaft (loosen the pinch bolt and remove it and then slide the arm, up and off the shaft). Take the shaft in your fingers an rotate it counter clockwise until you feel it come up against the internal spring. Replace the arm in the correct position, tighten the pinch bolt to 9Nm. Don't overtighten it, the arm is die cast and won't take a lot of torque. You'll strip the threads.
Most bikes (not all) have 2 reference punches, one on the shaft end and one on the actuator arm. You'll have to get down there to look and look closely. If they are there, just align the marks while holding the actuator shaft (with your fingers only) against the inernnal spring. That will put the actuator arm in the correct position.
Hopefully, the Rivco instructions don't advise taking tha arm off the shaft to install the risers because it's easier in the long run to just loosen the cable adjustment nuts and and remove the cable, but then I don't consider the folks at Rivco to be the brightest bulbs either.
Don't forget to set the correct freeplay at the handgrip. 2-3mm of slop between the base casting and the handlever. Without the freeplay, the acruator spring (internal) rides the lifter and failure of the lifter mechanism will result in pretty short order. ALWAYS maintain that 2-3mm at the handgrip. Check it often, like everytime you ride.
The is little movement between engaged plates and free plates, maybe 0.250" or less. That's why it's a wet multiplate clutch versus a dry unit. Dry clutches take much more movement to disengage.
A shop manual is a good thing. I suggest purchasing one.