The '78 550 goes as follows:
1- Loosen up all the adjustment points, the lever adjuster and the cable adjuster.
2- note that on the clutch arm (where the cable attaches and moves the part on the engine) there is a notch. On the clutch housing there is a another notch. When you move the engagement lever upwards with your hand, you should see the lever stop at the point where the notches line up together.
3- If the notches don't line up, loosen the adjuster locknut on the bottom front of the clutch housing. Turn the adjustment screw while holding up on the lever. Turn the adjusting screw until the notches line up. Retighten the locknut.
4- Adjust the cable, starting from the main cable adjuster at the clutch end, and then finally adjust as the handlebars.
5- Test ride bike.
Hope this helps.
