Are you saying the starter will not turn over?
If that is the case........
Recondition the starter Solenoid points
Starter, Starter Relay, Wiring Harness, Battery, and Plugs Tricks
Next time park ZR-1 on a flat surface and you can easily have someone sit in drivers seat with ignition on and in second gear with clutch depressed. You push the Z a bit (easy on flat surface) and the "someone" pops the clutch and you are started
Reconditioning the Starter Solenoid is a must in all my Top End Restorations as well as installing the Starter Relay 
Make sure the "someone" is a friend because when the ZR-1 is started, the "someone" may want to take a test drive