I'm thinking you could unscrew the circular plug from the center of the left-side stator cover and see if the crankshaft bolt spins when the starter is engaged.

If the motor is spinning, put your thumb or some other soft plug into the spark plug hole and see if there is any compression at all. Or use the compression tester with the gauge removed and thumb over the hole where the gauge goes.

 

There is some compression but I dont think 100 PSI... what can cause this?

 

So, the KACR (Kawasaki Automatic Compression Release) causes one of the exhaust valves to open a bit during low rpm (starting). It will result in low compression readings, but I don't know how low. It should be disabled for true compression readings. This can be done by removing the cylinder head cover and carefully removing the spring from the KACR.

Other obvious causes of low compression would be valve or piston ring issues.