Shifter

I have a 1975 Kawasaki KZ Z1 and have been restoring it for several years. Coming down to the last few things and have a problem. I tried to start the engine using my kick starter. It went about 2 revolutions in neutral and that's it!! Won't turn over! Any suggestions? Haven't opened or worked on internal guts of engine or tranny.

Remove your spark plugs
put the bike into first gear and rotate the rear wheel backwards.
If it moves backwards ok then try turning it slowly forwards.
If it feels like its jamming STOP . do not try to force it forwards or backwards.

This will hopefully tell you if the engine is turning ok.

If not I would suggest removing the rocker cover and points cover.

rotate the engine with the large nut (17mm?) under the points cover and check if the cams are rotating and if you can see the pistons moving ..
this should tell you if the cam chain is ok and let you check your cam timing
You can also check that there are no abnormal shim clearances.

Make sure not to pull the clutcg in while kick starting motor.

I did everything you suggested and all is ok in those areas. I spun the wheel and it went backwards and forwards. When I removed the points cover and tried to turn to crank, it turned about 1/2 revolution and then stopped. Wouldn't go any further. Hope this explains my problem so far.

When you turned the back wheel was the bike in gear?
I ask as with the clutch out it should turn the engine as well

I would try leaving the bike in neutral
Take out all the spark plugs
Have someone pull the clutch in or cable tie it back to the bars.
Try GENTLY turning the engine over with the large nut behind the points casing.
If the engine turns over freely you have a gearbox problem.

If the engine still jams you probably have a valve touching the piston ,or another valve.
You are going to have to remove the valve cover and check if the valve timing is right.

Do you have a workshop manual?