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Z1300 Coil Swap with Auto Coils | ||
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Last Update 1/5/10
BE ADVISED: I DO NOT RECOMMEND THIS INSTALL!
While it may be a little cheaper than going with Nology coils, any coil install where you have to install a ballast resistor is a bad idea in my opinion. One of the best things about the Nology and Dyna coil install is that we can get rid of our stock ballast resistor which causes so much problem. Using a resistor on a coil lowers the available spark voltage. The best reason to change coils to begin with is so we can get maximum spark voltage so the bike will run it's best, and get good gas mileage. I include these installs because it is possible to make our bike run on this setup, and I'll admit that it's probably the cheapest coil install available. But if you choose to use these, don't write me wanting info on how to make them work properly. I don't use them, I don't recommend them, and I don't want to answer questions about it. david@kz1300.com
Submitted by: Bob Fieldhouse in Canada
There are a number of 6-cylinder cars in the junk yards with high output coil packs suitable for retrofitting on our bikes. We need a coil with a primary resistance of 2.5 - 3.0 ohms. The original ballast resistor on the KZ models should measure about 1.7 - 1.9 ohms. With that said, you could keep your original ballast resistor and fit a coil that measures .9 ohms and you'll have the needed 2.5 ohms total resistance. Or better yet, if you can find coils that measure 2.5 - 3.0 ohms to begin with, then all you have to do is wire them up. I haven't seen automotive coil packs with that high of an ohm reading though.
One issue with using a ballast is what happens when it goes bad. If the ballast fails then one of two things happen. It shorts out and the current draw through your igniter increases to the point that the igniter burns up very fast which is bad, or there's an open circuit and there's no current flowing at all which is better. They're supposed to fail to an open circuit. Another issue is the fact that when you go through a ballast it drops voltage to your coils. So instead of having a full 12 volts for example, you may only have 10.5 or 11 volts. Dropping the voltage on the primary side affects the secondary output and gives you a weaker spark.
To me, using a ballast is a bad idea considering there are bolt in 2.7 - 3.0 ohm coils available aftermarket or ones you can retrofit from newer Kawasaki's, Honda's, etc.. For example, the ZN1300 Voyager uses a 2.5 ohm coil that will bolt right in as we've talked about on the FAQ page and elsewhere on this site. Though they're not high output, they're a safe and easy install.
The real issue here is that we want a hotter spark than the originals since it makes the bike start easier, run better at higher RPM's and get better fuel economy. I've seen some ratings posted on different GM coil packs and they were in the 35kv range. I think the Accel and Dyna coils are a little higher output than this and they're OK even at their rated 3.0 ohms. However, there's at least 3 issues with Accel coils that I'm aware of:
#1, is cost. They're about $60 - $120 each depending on who you buy from;
#2, I recently heard that the 140403 coil we use is no longer being manufactured by Accel though there are many new unsold coils still in circulation; and...
#3, I've had some new Accel's where the primary resistance measured way too high, like around 4.0 - 4.5 ohms. If the primary ohm readings are too high, you'll also loose secondary output and you'll have weak or no spark. Dyna's are historically much cheaper than Accel's, and they're still being manufactured as far as I know, which no degradation issues causing improper resistance readings.
Still, it's good to look at what other alternatives are available to us. Recently I've decided that Nology coils have been the best pick in my opinion for new high output coils. Dyna coils have always been a good coil for our bikes. There may be a number of viable coil packs out there that we can use and if anybody knows of something in particular that uses high output 2.5 ohm coils please email me at david@kz1300.com with info and pictures if you have them. I think the following pictures are of .8 ohm coils off a 88' 3.0 liter V6 GranAm. He said with the ballast, they measured out at about 2.4 ohms. I'd rather see a reading slightly higher myself like in the 2.7 - 3.0 ohm range to be on the safe side.
Here's the email Bob sent me:
Here are some pictures of how I fitted the G. M. coil
assembly, 2.4 ohms per circuit from the coil terminal to the input side of the ballast
resistor. I re-gapped the plugs to .045". The 6 holes in the coil box
were exactly right for tapping 1/4 x 20. I had some nylon bolts so that's what I
used - no rusting! Touched the starter and it was running. As for the tool
compartment... pick your priorities! I only ride it on weekends, one hour each way to the drop-zone.
A cell-phone is the only tool I need!
Coils will stay cooler, cam-cover is now easily removable, more air-flow over top of engine.
Here's another install on a 79' A1 sent in by Kevin Walker. He mounted used DIS ignition out of a 2002 Dodge Caravan and got a reading between 2.3 and 2.4 Ohms with the ballast.
Here's my Accel test coils that I use to test run engines with, and these still measure 3.0 ohms as they should, even though they are pretty old coils these days. david@kz1300.com
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