Clutch go completely slack

So I have an 82 750 twin. Kick start. Took it out for the first time after getting it running good and it would stall trying to put into 1st. Got it going brought it into 3rd gear and it died on the side of the road and absolutely no Kick start and no clutch pressure. Brought home opened clutch panel put it back on and it would start again then pulling clutch in there would be a pop and then slack and no Kick start. Worm gear has some serious wear on the thing could this be the problem?

Did you do a clutch adjustment or replace the cable prior to the problem occurring? I would clean, inspect & lubricate the mechanism and operate it by hand to check it. service the clutch cable as well. When you reinstall the cable, be sure to use a new cotter pin which helps to keep the cable end seated during installation. Then adjust the clutch & cable as per the Kawasaki manual.

Clutch adjustment. not sure about the 82 750-CSR, but on many 80s models you're supposed to turn the clutch release adjusting screw counterclockwise first until hard to turn, then clockwise 1/4 or 1/2 turn, then tighten the locknut (my 650-CSR is 1/4 turn).
Some manuals are ambiguous as to the direction. counterclockwise first is kind of counter-intuitive.

which worm gear has wear??

That bike should have the EZ-pull style clutch release mechanism, not the earlier worm-style. That mechanism can easily be installed incorrectly so that the cable end can pop out when the lever is pulled. As I recall, the lever should be slightly below level when properly installed. Check the factory service manual to be sure.