Below is the article I found on it, if I should quote the source, please let me know:
Coil Upgrade
Z / KZ1300 AW82 Coil Upgrade Modification.
For those of us with CARB model Z1300’s, there is a very worthwhile modification that can be carried out very easily to increase the power and quality of your spark. This will improve your starting, general running and provide an increase in MPG if carried out correctly. It’s worth looking at your own bike first to see if the modification has been carried out already, so this is how to find out:-
Remove your petrol tank and look at the 3 coils positioned just behind the headstock, up inside the frame. With a torch or inspection light look very closely at where the black HT Leads come out of each coil at the front. If the HT Lead is machined directly into the coil body itself, you have got the original factory low performance coils. Next, just to the left of the coils on the outer left hand side of the frame, you will see your BALLAST RESISTOR. This is a small white match box sized component with 3 PINK WIRES going in and ONE YELLOW WIRE coming out.
IF YOU’RE HAVE THESE COILS AND BALLAST RESISTOR, YOU ARE RUNNING WITH A VERY OUTDATED IGNITION SYSTEM AND WILL BENEFIT FROM CARRYING OUT THIS MODIFICATION.
The Modification Procedure.
To carry out the modification, you will need the following items and disconnect the battery + pole before proceeding just to be safe.
1). Three, Replacement AW82 coils.
2). About 5 foot of good quality NEW 7mm HT Lead.
3). 10mm Spanner
4). Pliers and crimping pliers.
5). At least 6 new flat spade type crimp terminals with waterproof covers, and a small assortment of male & female crimp terminals.
6). Soldering Iron, flux and solder, if not using crimp terminals.
7). Around 1 to 2 hours of spare time!
The first thing you must find are three AW82, 2.7 OHM coils to replace the old ones. It is essential that you use only the coils recommended, not just any coil that looks the same. The best way to define the correct coil is to ensure it has the reference AW82 on the body. A lot of coils look exactly the same as the AW82, but produce a higher OHM rating, and if used will quite simply burn out your expensive CDI unit very quickly, so don’t let the nice man at the breakers tell you “there all the same mate”, as I can assure you they are NOT. AW82 coils were used as standard equipment on many late 70 and early 80 super bikes such as Honda CB750 & 900F (16v models). These coils differ from the old Z1300 ones by having SPADE connectors for the electrical feeds and also DETACHABLE HT Leads. These coils are often up for sale on EBAY or found in breakers quite easily and cheaply. The problem is you need 3 identical coils, and obviously a 4 cylinder bike will only have 2 per bike. If you can examine the coils before buying them, take a close look at the condition of the SPADE TERMINALS making sure they are not snapped off or badly corroded. Also, you need to make sure each coil has the CONE SHAPED SCREW caps present that hold the HT Leads into the coil body, these are very hard to find without buying a full coil. For the “TECHIES” among us, you can also check with a multi test meter to ensure the primary resistance of each coil is not more than 2.7OHM and safely no less than 2.5 OHM, but to be honest I have never had an AW82 coil break down on me yet.
Once you have the coils. You need to remove the old coils from the bike itself taking note of which wires went to which coil and which cylinders the coil supplied, as you will need to wire the replacements in the same order and place. You will find that the old coils each have 2 wires running to them. All will have a PINK wire, which is the NEGATIVE contact and the other will be either GREEN, BLACK or BLUE depending on which cylinders that coils is supplying, these are the POSITIVE feeds from your CDI Unit. As the old coils DO NOT have spade terminal contacts, you will need to cut both wires to each coil as close to the coil body as possible and solder or crimp new SPADE TERMINALS onto the ends of each wire. Next, taking note that the AW82 Coils have a + and a – marked on them above the spade terminals, slip the wires onto the correct connectors. Its well worth doing this at this point, as it is very difficult to get them on when the coils are re-fitted. At this point, it is also worth cutting suitable lengths of new HT Leads with plenty spare, to reach each spark plug, and refitting the correct PLUG CAPS.
DON’T BE TEMPTED TO USE THE HT LEADS THAT CAME WITH THE REPLACEMENT AW82 COILS, AS IT IS PROBABLY 20 YEARS OLD, SO TAKE THEM OFF AND DISCARD, AS IT SILLY DOING ALL THIS WORK AND USING OLD HT LEADS.
Make sure you replace the coils using exactly the same spacers and washers as the old ones. The AW82 coil is exactly the same shape & size as the old coils, so will be an exact replacement fit.
With all three AW82 coils now in place, we can move to the BALLAST RESISTOR. Carefully remove this from the frame with a 10mm spanner and disconnect or cut the YELLOW wire from it and ALL 3 PINK wires. The BALLAST RESISTOR is no longer needed. What you need to do now is to somehow join ALL 3 PINK wires together and connect them to the single YELLOW wire. I much prefer to do this with solder, but as long as crimped connections are good and solid, it will do the same job, as this is now the EARTH or POSITIVE connection of your coils.
Check all contacts are good and clean with light wet & dry sand paper and apply a little Vaseline or copper grease, re-connect your battery and go ride the best 6 cylinder bike ever produced……..with an upgraded ignition system !!
