I don't have a Z50k2 ignition coil at the moment, but these values should be close.
Resistance from small black wire with bullet connector: ~1.5-2.5 ohms to frame of coil
Resistance of large wire for spark plug: ~10k ohms to frame of coil. If you have a resistor type plug cap, add about 5k for this reading.
About all you can do with it off the bike is test the resistance of each winding.