Resistor ignition coil z1000 mk2

Good evening, I am a new user and I am writing to you from Italy. I hope you can help. I bought a kz1000 mk2 to restore. I have a problem with the coils because they were not present. I purchased 2 new 4ohm coils. I have seen on the wiring diagram that there is a resistance. On various sites I have found 2 types of resistors: 20 w 0.5 kohm and 30watt 1.7 ohm. Which one should I buy for my bike?

AFAIK, 4 Ohm coils don´t need any ballast resistors.

Like Scirocco said, the 4 ohm coils didn't use resistors. they were used on points-driven ignitions.

The early electronic ignition coils used ballasts, but only because the proper coils were not available. Nowadays you would just get 2.3 ohm coils and eliminate the ballast (most coils from 2.2 to 3 ohm will work and won't need a ballast). But that is only if you have electronic ignition.

Thanks for the replies. I have the electronic ignition on this bike.I can know from you how to calculate in the future if the resistor should put it or not put it?

If you don't know what resistance is in the coils you can measure the primary side. If 2 ohms then you need the resistor. If 4 ohms then you don't need it.