KLF300 Bayou 1994 EU with weak or no spark issues

[Params_sweden]

Hi, I have an EU '94 KLF300 Bayou with ignition issues. I got it last summer and used it for about 20 hours, then one sunny day we used it for about an hour, parked it, and then it didn't want to start again. It has a *really* weak spark, I've only been able to see it once while testing. 

I'm just getting started on this, I'm going to go through all the weak/no spark trouble shootings from the manual. Since I've already invested like 10 hours digesting the manual and forum threads that I possibly can, I thought that it would be nice to create a thread like this in case I come up with a solution that can help someone else.

So far I've replaced the spark plug, I will replace the spark plug cap with a NGK VD05F (5kOhm resistance). I'm going to check the resistance in the pickup coil, stator coil and ignition coil next. I have tried two CDIs, right now I mounted the original CDI which actually gave the most output to the spark plug out of the two

A question for you, is it possible to make any assumptions about the CDI by measuring the resistance like in the manual? There's a "resistance table" that you can refer to when measuring between the different connections. I'm asking because I haven't yet seen anyone in the forums that has mentioned that they've measured the CDI resistances and made any conclusions from that.

I'll attach a photo of my Bayou

Pär, Sweden

[Gwbarm]

I haven't read the Kawasaki manual but in the Yamaha , it has you check for power and ground at the CDI, check for Coil wire continuity to CDI, check pickup coil resistance about 550, check anti rotation coil resistance, its low maybe .2, make sure both coils are making voltage, actually the yamaha manual does tell this I added it, it does not tell what the voltage should be, and if all these tests are passed replace the CDI.  

Oh by the way, nice looking bike, very good condition, I like the Moose.

[Mech]

If the books gives a table or resistances for the cdi then yeah sure, do that test.

But if the cdi is firing the spark plug at all it's probably not the problem. I'd suspect the ignition coil or it's lead.

Some modern systems with resistor leads or caps do have very skinny sparks that are hard to see in bright light.. If you have a timing light put that on and see if the spark is regular.

And I suppose you have checked for fuel problems ? Isn't flooded ? Hasn't run out of fuel ? Getting fuel right into the carb ? Have you tried the carb drain screw at the bottom, it might let water out, or reveal a lack of fuel flow if the tap is on.

[Mech]

I was reading the book and I see if has several different spark plugs they use, some resistor and some not. If you have a resistor cap which some do, then you won't need the resistor plug, and if you do use a resister plug and cap the spark will be weak looking.

Next, it's not a cdi, it's a twelve volt coil, it has more resistance than a cdi coil. Be careful if buying a new coil. It needs good power and earth connections. It would be a good idea to check the full 12 volts is getting to the coil through the switches and fuses etc.. And that it has a good earth.

You only need to check the one pickup coil resistance, the charging for the battery is a separate system.

[Filthy_Mule777]

I'll be following this thread, I'm experiencing similar issues with a customer 98  bayou 2x4 KLF300b. I've changed every electrical component on it twice and in a couple instances the times. Still no spark, I am baffled.

[Mech]

Well Mule, if you've changed all the individual components, surely it must be a wiring problem ?

Have you used an ohm meter to check the continuity of all the wires ?

Have you checked the power supply and the earth with a "voltage drop test" ?

Just using an electrical gauge to check for 12 volts doesn't show up bad connections under load.. The voltage drop test checks how many volts are present under the load the circuit normally carries under operating conditions.

[Filthy_Mule777]

Mech, thank you for replying. I've only tested for continuity and 12v presence, as that is the limit of the Kline tester I own. I don't have one that is able to either test for peak voltage or ohm's under load. I need to get a better tester but until I can get this thing outta the bay I'm strapped for cash, I also desperately need the repair manual for it but again finances don't allow it currently. I've been stuck in this thing for four months now, and fortunately the customer is extremely patient and understanding (he realizes he talked me into "looking" at it for him). The thing(s) that really gets me is 1. There are literally dozens of threads just like this with nearly identical issues that no one ever posts the cause and repair only that they either sold it unfixed or that they were happy to report it was fixed and they were enjoying using it again, only to never be heard from again when people inquired what the fix was. I have been able to get nearly all my component values/specs off threads like this or through the manufacturers of the replacement parts I've purchased. There was one thread (I thought on this forum) a gentleman posted about having a "hack" for the CDI, he had listed a part number for an ignition coil from auto zone to replace the CDI and it was like $25 vs the $500 that kawasaki charges, however I've had no luck in finding it again.

[Params_sweden]

I really appreciate the enthusiasm here, thanks! I did a test light run a couple of days ago, it's just wired directly to the spark plug without the cap, video attached. The test light is weakly flashing I think, but the spark itself isn't visible to the eye. I found a video of the spark on a Bayou linked below, where the spark is bright and clear when testing at the same spotas I've tried mine on.

I haven't had time to look at it this weekend, but should get out and check the things you have suggested in the next few days. I'll concentrate on the electric system for now because of the seemingly non-existent spark.

Regarding the carb, it's a China replacement mounted by the previous owner. I haven't checked the carb function at all so far! I got the original carb and it's in as good condition as the bike exterior judging by the look of it, I'll clean it up and mount it in when I get the spark sorted out.. one thing at a time  

My plan is to start with the "volt drop test", then check the coils, then the CDI. I'll let you know how it goes! @Filthy_Mule777 keep me updated if you find something

Bayou spark https://youtu.be/hzZPzaiMRdc?t=90

[Filthy_Mule777]

4 hours ago, Params_sweden said:

I really appreciate the enthusiasm here, thanks! I did a test light run a couple of days ago, it's just wired directly to the spark plug without the cap, video attached. The test light is weakly flashing I think, but the spark itself isn't visible to the eye. I found a video of the spark on a Bayou linked below, where the spark is bright and clear when testing at the same spotas I've tried mine on.

I haven't had time to look at it this weekend, but should get out and check the things you have suggested in the next few days. I'll concentrate on the electric system for now because of the seemingly non-existent spark.

Regarding the carb, it's a China replacement mounted by the previous owner. I haven't checked the carb function at all so far! I got the original carb and it's in as good condition as the bike exterior judging by the look of it, I'll clean it up and mount it in when I get the spark sorted out.. one thing at a time  

My plan is to start with the "volt drop test", then check the coils, then the CDI. I'll let you know how it goes! @Filthy_Mule777 keep me updated if you find something

Bayou spark https://youtu.be/hzZPzaiMRdc?t=90

Thank you for starting the thread. I'll most definitely share any progress I make or anything else that maybe helpful (if I find such, not to say Mech, that your suggestions weren't helpful because they are I just don't have the means of performing them at the moment, but I appreciate any and all help/ideas/information). The second shorter video was you testing for your spark? If so I really think you should be getting fire even if it is a bit weaker than the YouTube video. Are you sure your getting gas to the cylinder?

[Mech]

Mule you should start a new thread..  Cut and paste from here and we'll try to get your problem sorted. And have you looked in the manual section on this site for a manual ?

If you have a volt gauge then you can do a voltage drop test.. What it is, is you bridge the suspect switch, fuse, or wire with your volt gauge and if the wire or fuse or switch is good, and has low resistance, then the gauge will show no voltage while there is a load going through the fuse switch etc, but, if there was a dirty contact, some or all of the power would go through the volt gauge and show up as a voltage.

To test a starter solenoid you bridge from one big terminal to the other big terminal with your volt gauge and it will conduct power through the gauge because the solenoids contacts are open.. Then when you press the start button the contacts should close and conduct all the power to the starter. While your finger's on the start button the volt gauge should read zero volts if the contacts are clean.

In your case, to test that the full 12v is getting to the coil, you put the volt gauge from the battery positive to the coil's live wire. With the key on the gauge should show zero volts in theory, but in reality wires have some tiny amount of resistance and so you might see perhaps a quarter volt on the gauge. If it has more than a half a volt showing it's too much and there is some bad connection somewhere between the battery and the coil. You can test the earths the same way. To test the earth you really want to test it under starting load, so you would put the gauge from the battery's negative to the engine or starter body. With the starter not going you will see no voltage, but if you operate the starter and there was a bad connection, or a bad battery lead say, then when you operate the starter some power would go through the gauge to the earth and you would see a voltage.

The advantage of the voltage drop test is that you are testing circuits with the load on them that they are designed to take. Just testing for a voltage with a gauge puts so little load on the circuit that it could have a bad connection/contact, but still have enough power getting through to run the gauge and show full voltage, but when we put the load on the voltage would drop low.

[Mech]

I couldn't see that link Params..  I think that if the ignition unit on your bike was playing up you would get no spark at all. That unit is only switching the power to the ignition coil on and off, it's not a cdi. It depends on a good full 12 volts to the coil and a good earth.

I suspect you could put a headlight bulb in place of the coil and it should turn on and off as the engine turns over. If there is a full 12v getting to the coil, and a good earth, then when the unit switches the power off to the coil, the coil should make a good spark. If the spark is weak, I'm pretty sure it will be the coil or lead or cap, not the switching unit.

You could test the coil by putting 12 volts through it momentarily and seeing if there is a spark at the instant you disconnect the 12 volts. If you connect one jumper to the coil, and then just tap the other jumper on the other low voltage terminal it should throw sparks.

[Gwbarm]

Your light video seems consistent, will it not spark at the plug even with the plug cap off.

[Mech]

I think a resistance check of the coil is first thing... The book says primary resistance is 1.8-2.8 Ohms, and secondary is 10-16K ohms

[Pod]

On 3/26/2023 at 2:45 AM, Filthy_Mule777 said:

I'll be following this thread, I'm experiencing similar issues with a customer 98  bayou 2x4 KLF300b. I've changed every electrical component on it twice and in a couple instances the times. Still no spark, I am baffled.

Same here on my 86, will follow the post as well have you guys checked out the regulator/ rectifier, I’ve seen similar issues on a snowmobile

 

[Filthy_Mule777]

4 hours ago, Pod said:

Same here on my 86, will follow the post as well have you guys checked out the regulator/ rectifier, I’ve seen similar issues on a snowmobile

 

From everything I've read seen about this particular ATV (it may be different with some other manufacturers) it should be able to run just fine without one at all but it'll only run off battery power until it becomes too weak to initiate a spark. But I'm no expert or even a well informed novice so I may have it wrong and I welcome anyone knowing different to please weigh in on the subject.

[Mech]

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.

[Filthy_Mule777]

11 hours ago, 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 just met print and frame this, it's not often I hear that, it maybe it's not often that I actually am, either way after I get it hung up every time have someone disagree or have av difference of opinion, I'm just going to point to that comment hanging so very pompously upon my wall!! Thank you Mech, you made my week!

 

[Mech]

Ha..  getting the quad going will make your week..

You need to check the resistance readings in the coil. You use an ohms gauge and measure between the two small wires for the primary winding, and then from the spark plug lead to one of the small wires for the secondary winding.

[kp3004x4]

On 3/23/2023 at 8:18 AM, Params_sweden said:

Hi, I have an EU '94 KLF300 Bayou with ignition issues. I got it last summer and used it for about 20 hours, then one sunny day we used it for about an hour, parked it, and then it didn't want to start again. It has a *really* weak spark, I've only been able to see it once while testing. 

I'm just getting started on this, I'm going to go through all the weak/no spark trouble shootings from the manual. Since I've already invested like 10 hours digesting the manual and forum threads that I possibly can, I thought that it would be nice to create a thread like this in case I come up with a solution that can help someone else.

So far I've replaced the spark plug, I will replace the spark plug cap with a NGK VD05F (5kOhm resistance). I'm going to check the resistance in the pickup coil, stator coil and ignition coil next. I have tried two CDIs, right now I mounted the original CDI which actually gave the most output to the spark plug out of the two

A question for you, is it possible to make any assumptions about the CDI by measuring the resistance like in the manual? There's a "resistance table" that you can refer to when measuring between the different connections. I'm asking because I haven't yet seen anyone in the forums that has mentioned that they've measured the CDI resistances and made any conclusions from that.

I'll attach a photo of my Bayou

Pär, Sweden

That's one beautiful bike

[Params_sweden]

Hi, I got out during lunch and concentrated on the ignition coil like many of you recommended me to. Primary resistance is 1.5ohm, secondary 8.56kOhm. Spec says primary 1.8-2.8ohm, secondary 10-16kOhm. I noticed right away that the coil is a replacement part, probably mounted before I bought it. I wonder if it had the same stats when the ATV worked?

The resistance is lower than the spec on both primary and secondary, would that result in a weaker or stronger spark you think?

Should I do your 12v test on the coil @Mech?

Thanks for your help everyone, I read all your comments Off to day care and pick up the kids.

/ Pär

[Mech]

And both of you guys, Param and Mule, both need to check your ignition coils are the right sort for 12 volt ignition systems.. The most common sort of coil now is for cdi, and you can pick them up for a few bucks. 12 volt coils are getting rare. Cdi coils are made to run on hundreds of volts. If someone fitted a cdi coil it's not going to make much spark from only 12 volts.

cdi coils have very low primary resistance, about point one or point two ohms. 12 volt coils have a primary resistance of about two ohms.

[kp3004x4]

I agree 👍

[Gwbarm]

I think your coil resistance is good I don't think that's your problem, I was also concerned with my coil specs on the aftermarket I installed resistances were not up to repair manual specs , but once I found my problem, it sparks good with the low spec coil. 

[Filthy_Mule777]

Is it just a lighting or shadow thing or is there damage/melted plastic in the first picture right underneath the terminal tab (on the primary/positive +side)? Mech I've got my oem ignition coil on it currently but have tried with both and gotten no spark. I haven't ohmed them both yet (at least not with the factory specs in hand) but I'll do that tonight and post the results. 

[Filthy_Mule777]

On 3/28/2023 at 3:24 PM, Mech said:

Ha..  getting the quad going will make your week..

You need to check the resistance readings in the coil. You use an ohms gauge and measure between the two small wires for the primary winding, and then from the spark plug lead to one of the small wires for the secondary winding.

True, also I'll try to proof read before posting so as to not give anyone an aneurism or brain hemorrhage.