KLF300 Bayou 1994 EU with weak or no spark issues

[Params_sweden]

On 3/30/2023 at 11:05 PM, Mech said:

If you connect the sparkplug and the jumper to the coils negative terminal, and then just rub the positive jumper clamp on the primary positive terminal it should make and break contact as it scrapes along and make several sparks.

I went out and did another test run, this time actually following your instructions here, jumper from coil negative to sparkplug (w/o coil cap), then jumper from spark plug to battery negative. Coil positive jumper scraping battery positive... not a sign of a spark, tried two spark plugs just to be sure. 

Hopefully my drawing is clear enough, test #1 is described in my previous message, test #2 is my latest test in this message..

/ Pär

[Mech]

Test one should have made heaps of sparks at the plug if the jumper was scratching over the coil's terminal..

You need a new coil and it should be a quite high resistance one..  About 2-4 Ohms..

[Gwbarm]

Did you do this same test with both coils.

[Params_sweden]

Okay, I ordered 2 coils, one from a local dealer (the one without spark plug cap, 40USD) and one from China (with spark plug cap, 10USD). Hopefully I'll get the local coil next week, delivery from China will take three weeks.

For reference I took screenshots of the units I ordered, I'll leave links here as well. When I get them I'll measure the resistance and post it here. Fingers crossed that they will get my Bayou running

https://www.merafritid.se/tändspole-kawasaki from Sweden

https://www.ebay.com/itm/393606999077 from China

/ Pär

[Params_sweden]

@Gwbarm I only have one ignition coil, however I have 2 carbs (original and china) and 4 CDIs (1 original, 3 china). I'll rebuild the original carb and mount it when I finally get her to start again

[Gwbarm]

Some reason I thought you had 2 and just wondered if they had the same resistance ratings.

[Params_sweden]

Np, I'll measure all my coils as soon as I get them, hopefully they match the OEM specs. Seems like the 1994 Bayou ignition coil specs differ from many other ATVs with 12v ignition, the few specs that I found have much lower and almost identical resistance on both primary and secondary, about half of what the Bayou has.

It might give a hint to why the Bayou seems to have a lot of electrical issues, judging by the amount of threads about it, unusual specs and sensitive system overall? Just a thought.. 🤔

/Pär

[Gwbarm]

I think from your test it appears the coil is not putting out what it needs, I was thinking maybe the ignition unit was bad, but now I don't think so. 

[Filthy_Mule777]

On 4/3/2023 at 1:12 PM, Params_sweden said:

Np, I'll measure all my coils as soon as I get them, hopefully they match the OEM specs. Seems like the 1994 Bayou ignition coil specs differ from many other ATVs with 12v ignition, the few specs that I found have much lower and almost identical resistance on both primary and secondary, about half of what the Bayou has.

It might give a hint to why the Bayou seems to have a lot of electrical issues, judging by the amount of threads about it, unusual specs and sensitive system overall? Just a thought.. 🤔

/Pär

I agree par which is strange to me considering the longevity of the platform, I mean they produced these things for thirty years, I understand Kawasaki having the astronomical prices that they do but you would figure with the amount of them out there at least one aftermarket company would rise to the top having gotten the specs right, seems their is a small fortune to make on klf300 electric system aftermarket parts. It's a rather criminal thing these companies are doing, you can't return electrical parts/components yet these companies/manufacturers have to know that they aren't within spec and then go so far as to advertise them as a replacement for the machine they know they won't work on, but they've already got your money with no recourse.

[Filthy_Mule777]

On 4/2/2023 at 1:04 PM, Gwbarm said:

Some reason I thought you had 2 and just wondered if they had the same resistance ratings.

I had two, and actually the third arrived today, installed it and like a idiot I allowed myself to be hopeful. But instead of a spark I only got more disappointment. I've put so many parts  on this thing multiple times that I've now stopped going to the customer (that I haven't spoken with in a month) for them to purchase whatever happens to test "bad" this time and I've started buying their parts out of pocket. The horrible thing is that had I been aware of the situation as I now am, at the start of this i would have insisted that the only way I would take the job is if he used only oem parts, and the unfortunate reality is that at the point that would have been the cheaper route not to mention 3.5 months faster!

[Gwbarm]

Sorry you guys are having so much trouble, im at a loss right now, maybe try a 350 chevy coil. I will download manual and take a look.

[Filthy_Mule777]

I was actually toying with the exact dang idea this past weekend. I tested the coil that was just delivered yesterday and could only get continuity across the two terminal posts but nothing from either post to the plug wires and then I removed the wire itself and tested directly to the screw/stab terminal that feeds the plug wire and got no continuity or an ohm reading. Which can only mean one of two things 1: I'm testing it wrong, 2: it's a bad coil off the shelf. Either way I'm still not getting spark which is a great Metaphor for this because I am literally stumbling around in the dark. I've been turning wrenches since I got my first bicycle and I've never been more frustrated or stumped finding and solving an issue and now it's happened it is a customer's machine. Thank God it's a long time customer and he's a patient guy!

[Mech]

Yup well you need to  have a coil that can produce good sparks off 12 volts when doing that No1 bench test above.

Once you have a coil that you know can produce good spark, then you can use that to test the rest of the system..

[Params_sweden]

4 hours ago, Filthy_Mule777 said:

... got no continuity or an ohm reading...

Just to make sure, did you set your multimeter to a high enough setting like 20kOhms when doing the test? I noted that my multimeter just says 0 if I test something with higher resistance than what I've set the multimeter on, like trying a 5kOhm spark plug with the 200 ohm setting

I'm waiting for the parts to arrive, I'll get the local spark plug on Tuesday and the China one in two weeks. Quite excited to see if they at least are close to the spec!

I downloaded some manuals for other similar 90s ATVs, all of them had similar resistance specs for the IC, about a third of what the Bayou has... seems like the Bayou is and odd bird as I speculated about before. Really wonder why the Bayou IC has such a high resistance compared to other ATVs, if someone with knowledge about these kind of electrical parts has a theory I'd be delighted to hear it!

/ Pär

[Mech]

The different resistances are probably because some are using old silicon transistors and big capacitors and circuits that draw power, and others will be using metallic oxide semiconductors.

Transistors are current operated, and metalic-oxide semiconductors are voltage operated. MOS just need to sense a voltage on their triggers to start conducting, they don't require any current at all compared to a transistor, which conducts in proportion to the amount of current being fed into it's trigger..

[Gwbarm]

There are about 3 posts with weak spark on these bayous, something is wrong, maybe they are are not playing well with the metallic-oxide semiconductors.

[Params_sweden]

Fascinating, that would make sense, I'll do some reading on this just to get a better understanding Mech! Seems like there's a weak spark epidemic going on

[Mech]

I suspect that old 12 volt coils are getting rare, in these quad bike designs anyway, and so every one is getting sold coils made for cdi, or some multi purpose coil that can/might operate on cdi or 12 volt.. 

A 4 ohm coil draws 3 amps, a 2 ohm coil draws 6 amps, a 1.2 ohm coil draws 10 amps..

[Jim Denton]

On 3/27/2023 at 3:38 PM, Mech said:

You are right Mule, those are not a cdi, they are just like an old fashioned points and coil ignition system except the points have been replaced by a transistor and the ignition timing is calculated and adjusted in the ignition unit. The coil and ignition unit both run off the battery.

I love this group of folks. Everyone shares their knowledge so freely and there isn't any fb type crap. Mech is this ignition the same as on my 91 Hilux 22re? I had to replace the ignitor once.

And I'll say it once again! I hate it when the sparkulator don't spark.

[Mech]

Not sure about the toyota..  The nearest thing to these is an old points and capacitor ignition.. Except they've replaced the points with a transistor. They did use then in cars, mostly with an optical sensor/trigger. This uses a pulse coil to trigger the firing.

[Gwbarm]

So im assuming it also has a centrifugal advance, to compensate for timing.

[Mech]

No, I don't think it has a centrifugal advance. They might fire the ignition at a low point on the rising side of the pulse coil's AC wave, in which case there is a natural advance as the voltage rises to the trigger point earlier with a faster moving magnet,(that's how most older cdi systems worked) or.. They use the change from rising to falling of the pulse coils AC wave to trigger it,(which is consistent and accurate no matter what the voltage or air gap), and then do a sort of calculation  for advance inside the cdi unit, which is how most of them have been for a long time now. Some motorcross bikes and road bikes have switches on the handlebars now to choose how much power you want.

The kawasaki with it's 12 volt system being triggered by the pulse coil, will be one of those two systems for timing, the only difference being most bikes now have cdi which use a low impedence high voltage coil, and the kawasaki is using a higher impedence low voltage coil.

[Params_sweden]

Today the locally bought coil arrived, and this one has the primary out of spec and the secondary in spec..  Primary resistance 4.7ohm, secondary 11.3kOhm. It's produced in China, it's not the same one as was mounted on the bike judging by it's size and material choices. I will hopefully have time to try it out today or tomorrow on the Bayou, hope it's this simple 🙏

/ Pär

Edited April 11, 2023 by Params_sweden

[Gwbarm]

This one is out of spec in the other direction it will be interesting to see what this one does.

[Params_sweden]

And we have a spark ✅ I have to get some fresh gas before starting it up though

The coil primary resistance is higher than the spec, any clues about how that affects the system? I'm thinking that the higher resistance maybe should be matched with a spark plug cap with a resistance that is lower than the spec. (I have little to none knowledge about electricity)

So excited to get her running!!

/Pär

[kp3004x4]

From watching the video,looks like it's firing erratically on spark plug ,should be more of a blue ish color also ,could be that the spark plug has been gas fouled.looks old also by the video ,might run but not top performance.many times you can hold a plug in a vice and put a lighter to the end and if it has been fouled it will burn the gas out. I would try that to see if it would help the spark a little bit or a new plug would definitely help.

[Params_sweden]

I think that many of the sparks happened between camera frames, so the sparks look very inconsistent on the video. It looks better irl.

As for the spark plug, it's only been mounted for about 15 hours (with the engine running) on the ATV, maybe the fouling is a sign of another issue?

I took a new spark plug and also mounted the 5kOhm cap, and made a new video. Looks better right?

/Pär

[Gwbarm]

Thats great, finally got it sparking, I think your spark looks good, 😀, how's it running.

[kp3004x4]

Yes sir that's better but just from sound,acts like it still not firing all the time could be me. Hope she runs

[Mech]

The higher resistance primary reading means it has more, finer, windings, and so draws less current Params. That's ok as long as the secondary windings are in a suitable ratio to the primary; so the step up in voltage is enough to throw the spark. If it was a multi cylinder and had to throw more sparks per second then it's an advantage to have thicker wires so they carry a heavier current and so magnetically saturate the iron core faster. In this case, of a slow revving single cylinder, there is plenty of time for the magnetic field to build, and so a low current through a lot of fine windings will do the job adequately and without using too much power.

The conventional coil in a 12v system builds up a magnetic field in the core relatively slowly while the power is flowing, then cuts the power and the rapidly collapsing field cutting through the secondary windings induces a high voltage. In the cdi system the capacitor gets charged up to hundreds of volts and is then discharged through the primary windings, and the rapidly expanding magnetic field cutting across the secondary windings induces the high voltage. One system induces the spark on the expanding magnetic field, and the other uses the collapsing magnetic field. The coils are different.

The resistor cap is not very critical and isn't dictated by the primary resistance. The overall resistance of the lead, cap and plug is normally about 25Kohms.