Basically two variations of the bike were used.
In earlier episodes the guys rode a Kawasaki
Z1-P which was a 900cc model..
Obvious differences between the bikes were Size and equipment.
The 900cc bike had Big front ("lolly-pop") Red Pursuit-lights, spoked wheels, no fork "covers".single disk-brake on the front/drum-brake on the rear, siren attached on rear saddlebag guard,(guard runs on a backward slant).
Smaller windshield, shorter exhaust.

later episodes saw the "Police 1000",a
much bigger machine.
larger windshield/exhausts.alloy wheels. Twin disks at the front. Single disk at the rear.
Siren mounted at the front engine guard, saddle-bag guards were "straighter" front forks fitter with "Gaiters."

Thanks to Dave for this information, and also many of the photos that are on the web page.