Z1 Leak Down Test

I've read that sometimes a fouled plug should be replaced but you may have and probably do have several problems just besides that.

I've had a plug be bad new.
Steve

I was refering to what happens sometimes when I forget to turn off the gas. A carb will leave me a puddle on the garage floor. I can't see a carb leaking when I'm riding.:whistle:

ok, if you park the bike and leave the gas on and it leaks onto the floor the valve or float height is off. Thats carbs 101. A high float level or bad shut off valve can/will cause a rich condition by flooding into the carb throat.

I checked the spark plug of the cylinder that is fouling (#1) by pulling it and holding it near the frame. There was a weak spark. I pulled the plug at cylinder #4 and did the same. It had a strong spark that snapped when I hit the starter button.

Using a cheap digital multimeter I tested the primary windings of the coil, that is I touched the probes to the two connections on the end of the coil and got a reading of 4.0 (setting was on 200). I believe that to be normal.

Secondary Method 1: I am a little bit fuzzy on how to check the secondary windings. I've seen two different ways on youtube (surprise). The way I think you are to do it is change the setting on the multimeter to 20k and touch one probe to the spark plug wire while touching the other probe to one of the connections on the end of the coil like in the first test. Reading should be between 10k and 20k. My reading was 1, same as before I did the test. I took the spark plug wire off the coil and touched the probe to the place where it connects on the coil and touched the other probe to the connector on the end of the coil, thus eliminating the spark plug wire. I still got a reading of 1. That would indicate the coil has a problem.

Secondary Method 2: The other way I saw to test the secondary windings was to touch the probes to the two spark plug wires. Doing that I got a reading of 13.4k. If accurate, that would indicate the coil is okay. But this method was not given in the manual or by one of the youtube videos. It was used in a second video that popped up when I typed in "How to check a motorcycle coil." I don't trust this method.

My thought is that I have a coil with bad secondary windings. I'm going to take it to the service department of the cycle shop and see if they will test it. The problem is I got the same readings on the other coil. One of its spark plugs looked a little weak when touching it to the frame and cranking the starter, but not as bad as the one that is fouling the plug. That's why I can't just compare the two coils because it is possible the other one has issues too.

Summary: My conclusion is the primary windings are normal but the secondary windings have an issue. Indicates a need for a new coil, and probably two since I get similar readings with the other coil. Anyone see anything wrong with my method and/or conclusion?

Sorry for being wordy but I want to be clear so that anyone may tell what I did and let me know if I did something the wrong way.

The coil I have is Dyna Coil 3.0 OHM 0910

Digital Multimeter is a cheap Cen-Tech from Harbor Freight.

I still need to check the float in the carb and I w ill need to check valve clearances.

bugsinmyteeth wrote: I checked the spark plug of the cylinder that is fouling (#1) by pulling it and holding it near the frame. There was a weak spark. I pulled the plug at cylinder #4 and did the same. It had a strong spark that snapped when I hit the starter button.

1) make sure you are using new spark plugs testing this way.

2) Try swapping wires between 1 and 4 and see if you have the same results or the weak spark moved from #1 to #4. Also, try swapping coils and see what your results are.

3) The factory Kawasaki service manual outlines how to test the coil using an ohm meter.

I don't think you should mess with anything else until you sort out the spark issue.

New cables and caps are a lot cheaper than new coils and more likely to fail as well, so it would be smart to replace those first.

Click here > Dyna Metal Core Spark Plug Wires

Old hard cracked plug wires can leak voltage, resulting in weak spark, when dry, and worse when damp, all of which may vary depending on position, placement and proximity to the engine head.

May resolve the problems by replacing the wires.

Dyna plug wires are available in solid metal core version, which come with non-resistance boots/caps already built-in.

If a resistance element is desired in the secondary loop, resistor boots/caps could be used instead. or R plugs could be installed with the non-resistor boots/caps.

Dyna also offers a resistor style graphite plug wire, which imo isn't as sturdy and long-lasting as is the solid metal core wire.

Good Fortune!

Kidkawie wrote: ok, if you park the bike and leave the gas on and it leaks onto the floor the valve or float height is off. Thats carbs 101. A high float level or bad shut off valve can/will cause a rich condition by flooding into the carb throat.

Or maybe just maybe there is some junk on the seat. Getting off subject for a bit but my carb float levels are right on using the clear tube method. I will still pee a little gas on the floor once in a while. I’ve owned 3 Z1’s and they at some point or another have done so. The EPA removed over flow tubes from motor Cycles which was a bad idea for carbureted bikes.

Kidkawie wrote:

bugsinmyteeth wrote: I checked the spark plug of the cylinder that is fouling (#1) by pulling it and holding it near the frame. There was a weak spark. I pulled the plug at cylinder #4 and did the same. It had a strong spark that snapped when I hit the starter button.

1) make sure you are using new spark plugs testing this way.

2) Try swapping wires between 1 and 4 and see if you have the same results or the weak spark moved from #1 to #4. Also, try swapping coils and see what your results are.

3) The factory Kawasaki service manual outlines how to test the coil using an ohm meter.

I don't think you should mess with anything else until you sort out the spark issue.

Thanks for the many responses, gents. I haven't had much time to work on it this week.

I agree, I need to stick to resolving this issue first. If it isn't the problem then I'll move on to the fuel and carbs. Even if it is the issue, I have a few other things that need addressed, like valve check and float height on carbs.

I got one of the coils off the bike. I'll reassemble and try your suggestions. I'm pretty sure I did some of those before but I tried so many things I kinda forget. Regarding following the factory service manual instructions on testing with an ohm meter, maybe it's a little clearer than my Clymer. I wasn't confident I understood the directions in the Clymer which is why I posted the details of my procedure in the other post. I went to youtube to get a visual but got different answers there. I'll get it figured out.

@Patton: your suggestion regarding plug wires makes sense. @Jackleberry said something similar. Plugs and wires may be a good idea any way.

Check the voltage at the coils. If it is lower than the voltage at the battery you will need to clean all of the connections between the battery and the coils. I always also install a power relay into the ignition circuit. Others here don't like the power relay mod but I have been using relays for years and I've never had any problems.

80B4 wrote: Check the voltage at the coils. If it is lower than the voltage at the battery you will need to clean all of the connections between the battery and the coils. I always also install a power relay into the ignition circuit. Others here don't like the power relay mod but I have been using relays for years and I've never had any problems.

Good point. (I'm a fan of the relay mod myself). However, bad connections/low voltage to the coil wouldn't really explain why the spark is weaker on one plug than the other on the same coil.