4.1 OHMS at the COILS?

OK, I'm going to give this a try. About three months ago I purchased a 1973 Z1.It has been sitting in a garage for approx. 7 years. Nice Bike; 1013 Kit, Bigger cams, undercut gears, Mikuni 29 smooth bores,chrome this and that, etc. The only thing different about the bike is that it has 1974 colors on the tank and side covers instead of the originals. The bike has an old Andrews electronic ignition kit installed. I went through the carbs and the tank and gave it thorough cleaning. Went through the carbs twice to insure that every thing was clean. Here is where I'm a little stumped. I started at ground zero leaving everything set where I found it. When checking the ignition, I find spark to each cylinder. (haven't determined if the spark that I'm looking at is a weak spark or not). Haven't messed with the timing yet. Purchased new plugs twice. I did purchase a Clymer manual to help me with my bike and read that if my bike has the original ignition, then the coils should have a resistance of approximately 3.0 ohms. Had it been a later model with electronic ignition, then the resistance at the coils should be 1.5 ohms. I read 4.1 ohms at each coil and suspect that both coils are bad and are the source of my problems (funny how both read the same. Do they go out in pairs?). I got my bike to run (barely idle) for approx. 2-5 seconds and that has been it. It should just light up and scream having checked everything else. Even with carbs out of sync I should get an decent idle. Can anyone of you KAWA guys give me a clue as to what to do next? I'm getting awfully anxious to ride. If I haven't covered everything, then let me know. Thanx.

Z1LEO

The Clymer can be wrong, as I discovered in a very similar thread I started a month or two ago. I have an electronic ignition, and apparently stock resistance for mine is 2.5 ohms, even though the Clymer says 1.5 (I'm measuring 2.8 and 2.9, respectively). So be aware that the Clymer could be wrong, perhaps cross-reference with a shop manual or other owners of the same year / model is in order. At least, it's worth it before dumping $120+ on coils.

I'm about to delve into the coil mod (described on WiredGeorge's website) to up the voltage to the coils by bypassing the stock harness. I don't know if it'll solve my startup problems, but I'm hopeful. It can never hurt to get a lower voltage drop to the coils from the battery! Basically the mod involves adding a relay to power the coils instead of going through the stock harness. Check out:

www.wgcarbs.com/index.php?option=com_con...view&id=12&Itemid=26

Hope this helps.

As Nick points out the Clymer may very well be off, been known to happen, 4.1 ohms doesn´t sound wrong for a points ignition. However that´s only half the story as the 4.1 ohms is only the reading for the primary coil windings, what does your secondary windings read (measured between the plug caps on each coil)? I don´t know the exact specs for your bike (should be in the manual), but I would expect something like 12-15 Kohms. It´s not likely that both coils would go out at once and since you have spark on all cylinders they´re probably ok.

Some things I would check before spending any money (assuming your problem isn´t fuel related which I would doublecheck):


- Are your coils (4.1 ohms primary) the correct impedance for the Andrews ignition? Appearently some Andrews ignitions use 2.8 ohm coils.

- Does the Andrews ignition use the mechanical advance unit like the Dyna-S and if so is your advance unit possibly stuck?

- Is the timing set correctly?

Hope this helps too.

Post edited by: OnkelB, at: 2007/07/06 12:05

:pinch: Double post.....

Post edited by: OnkelB, at: 2007/07/06 12:04

Maybe a stupid question but you never know....Did you unplug the coils before you testes them??

I suspect you have Andrews coils. The 4.1 Ohms is fine. I suspect you need to check your ignition wiring to ensure the pickup coils are wired to the coils properly and that your ignition timing is correct. Before mucking with the ignition though, I would check compression in all four cylinders. Do it using a compression gauge and hold the throttle open. If your compression is not up to snuff, likely you need to adjust the valves or do some engine work and all the ignition work in the world won't make the bike run. I know of no KZ that uses 1.5 Ohm primary resistance coils... could be out there but not a 73-80 model. Some of the later bikes used 2.5 Ohm coils but also used an inline ballast resistor to get the total primary resistor up to 4 Ohms for use with an IC Igniter ignition.

NOT A STUPID QUESTION!!! AND THANKS. I DID REMOVE THE PRIMARY WIRING TO THE COILS BEFORE DOING A RESISTANCE CHECK. HOWEVER , I DIDN'T REMOVE THE SPARK PLUG WIRES; WOULD THAT HAVE GIVEN ME A DIFFERENT READING?
THANX,
LEO

Post edited by: Z1LEO, at: 2007/07/06 17:20

THANKS FOR THE REPLY. YES, I AM USING ANDREWS COILS AND ANDREWS ELECTRONIC IGNITION (WON'T KNOW UNTIL I TEAR INTO MORE). THE STEPS YOU RECOMMEND IS WHERE I WAS HEADING NEXT. THE BOOK WILL COME IN HANDY FOR THAT. SO HAVE THOSE WHO HAVE REPLIED TO THIS FORUM. THANX AGAIN.
LEO

GONNA CHECK IT OUT....THE SECONDARY RESISTANCE AND THE POSSIBLE STUCK ADVANCER THAT IS. HOWEVER, YOU DID MENTION POINTS IGNITION (MINE IS AFTERMARKET ELECTRONIC). DON'T KNOW HOW OLD IT IS. NEVERLESS, AS A NEWBY, I'LL DO THE RIGHT THING AND CHECK EVERYTHING. THANX AGAIN,
LEO

THANKS FRIEND. I'LL RAISE MY BEER IN THE DIRECTION OF MEDFORD, MA AND TOAST TO YOUR GOOD HEALTH.
LEO

Specifications on KZ1000J coils is 1.8-2.8 ohms.