Hi Nero, to answer you question, if I understand correctly You mean which polarity goes where on the coils primary connections, that's what I presume. Look at the schematic below: Positive from the battery goes through the chain: Fuse, Main switch, Ignition switch, Engine stop switch – to the resistor and so it brings the positive to one pole on the ignition coil primary and the other pole from the coil will be automaticity negative (which goes to the igniter).
In the system Z13 uses, the ignition coil consist of two windings inside: primary and secondary and they are galvanic separated from each other. I don't have original coil but on AW82 TRI for example, plus is on the top and minus on the bottom (picture) when looking at the coil from marking site. If You don't know which pole is plus and which minus on You after market ignition coil than just connect the wire from after the resistor (the pink one) to one of the primary connections on the coil and from the other connection on the coil connect to the igniter (black, blue, or green wire depending on the coil number 1, 2, or 3). The reason being for the minus connection is because black blue or green wire goes from coil through igniter's power transistor to the negative or to the ground if you will, when the transistor is conducting and so its ''charging'' the coil with energy as seen on the second picture. (when current flow stops there is the spark) The secondary winding in the ignition coil: one end of the wire goes to one spark plug and the other end of the same wire in the coil goes to the other spark plug so there is no polarity in it, (it must only discharge through the spark plug) and its only reflecting what happens in primary coil.
Now once again but with out the academic crap:
One of three pink wires from resistor to one of the primary connectors on the coil, and black blue or green wire to the other primary connector on the coil.
IMPORTANT and
VERY important: Sum of the resistance of the coil and the ballast resistor must be between 2,7 and 3,8 Ohm (taken from rep manual Maintenance, Electrical p. 240, 241) because it limits maximum current flowing through the igniter. If you resistance is less than specified then igniter burns and if more than you spark is so weak it will barely ignite the fuel charge in the chamber under pressure.
Hope it helps.