Clutch pedal does not return

The factory put that spring on there to help you hold the pedal down at stopsigns and such. It is calibrated to work with the factory B&B 3-finger clutch, which takes a goodly effort.
A diaphragm clutch works differently, and does not have enough power to overcome that spring, hence the recommendation to remove it. Be careful, she has a lotta power.
Don't lose it cuz if you ever go back to a 3-finger clutch, you will again need it.