If these are late model stock levers ('71-'75), slacken the adjuster completely, aligning the slots to allow the cable to slide through. Then remove the locknut from the lever pivot and unscrew the lever pivot screw. Slide the lever out and turn the cable to align with the slot in the lever. You will not have enough slack to remove the cable until you remove the lever from the perch.
Installation is the reverse.
Ron L.