Kawasaki Brute Force 200 same as Kymco MXU 270

[jpz]

1 hour ago, Mech said:

You need a good 12 volt supply to the ignition coil. Without any voltage drop from the battery to the coil when it's under load. The load should be about four amps.. A car headlight bulb would be enough load to test the 12 power supply to the coil.

The ignition unit shorts the coil's negative terminal to earth for a few milliseconds before it wants a spark, then disconnects the coil from earth at the instant it want's a spark. The ignition unit also controls the ignition timing, and in that bike it has a wire coming from the gear change indicator unit to the ignition unit which they say to check for no spark situations. (I see you do get a spark now if the spark plug lead's cap is off..  That's good. ).

The ignition unit has to have a good earth so it can earth the coil properly. The unit's earth needs checking for voltage drop under load. A car headlight in the place of the coil will be a good load.

Since you do in fact have a spark though, I'd suggest you leave the spark plugs cap off and use a split pin or a bit of bent wire poked down the end of the HT lead and connected to the spark plug, to check for spark and try to start it. It's possible you are using a resistor plug and a resistor cap, and possibly a resistor lead on the coil..  Each of which makes the spark just a little thinner..

We seem to be on the same page with our troubleshooting. However, I'm still under "admin review" for each post so it may be a few hours before you see this and my previous 2 posts.

I will try connecting a headlight bulb in place of the coil and see what the result is.

I actually have connected a wire between the capless coil and the spark plug. The spark was intermittent and weak (had to turn off all the lights in the garage to see it). I didn't try starting the quad that way, just had the plug against the block. Also of note, in order to see that spark I had to decrease the plug gap to .4mm. When set to factory speck of .6-.7mm I do not get a spark.

The plug I have is a resistor plug, so I'm very curious if you are onto something. The plug itself has about 6 ohms, the boot had about 5. combined they had about 11 ohms. I'll have to look into finding a non-resistor plug.

The ignition unit has me completely stumped when trying to test following the information in the manual. If I'm understanding the chart correctly, one side of the diagonal line is for the positive lead, the other is for the negative lead.  When testing this way, I don't get anywhere near the same results in the manual. Am I misunderstanding the chart?

[Mech]

Yeah that's right. Some of the figures are ohms, some are Kilo-ohms, and some and Mega-ohms. You have to have the test leads the right way around. At the top left of the chart it shows + / -.

If your coil has a low ohms reading though(which it has) then it will be drawing a bigger than standard current and will be straining the current flow.

I think you need to check what sort of spark the coil has if you use a 12 volt battery and two jumper leads  to fire it off. Then you will know whether the coil is capable of making a decent spark or not.

[Gwbarm]

Chart is a little confusing, the way im reading it :Blue/Yellow +, Green/Gray- ,should give you a reading of 12.73M OHMs, Blue/Yellow+, Green/White-, should give reading 90.4K OHMs, etc. 

[Mech]

You have to go through using the + lead on one wire at a time from the top row of colours, and checking you get the right figure for each of the other wire colours in that column. Then you use the negative lead on one wire colour at a time from the column on the left, and check you get all the figures from each wire on that row.

Blue/yellow and Green/Grey give different readings depending which way the leads are applied. There are diodes in there stopping the ohms test going one way.

 

Blue/Yellow positive, Green /Grey negative gives 12.73 Mohms.

Blue/Yellow Negative, Green/Grey positive gives infinity.. 

[Gwbarm]

What he said, I forgot to mention the diodes.

Sorry, just say your earlier post, I just meant confirm you did have 12 volts going to the coil, and you have done that.

[jpz]

Well I'm back on this, and still having zero luck.

First, I installed a car headlight to the leads for the coil. I cranked the engine, and after a few rotations the bulb started to flicker. The longer I cranked, the brighter the bulb got but it never came close to full illumination. Was more or less making the element glow slightly.

Second, I went through the ignition unit inspection chart, and not a single one of my readings came back as mentioned in the chart. They all come back significantly lower than what the chart shows.

I'm really stumped here. I can't make sense of this machine at all. Functionally I can get every individual component to work. It just seems like the ignition system is working poorly and not generating enough spark to jump the gap on the properly gapped plug.

I still need to try a regular spark plug without a resistor.

I'm open to any additional suggestions.

 

On a positive note, I seem to have been released from Admin approval as my last post appeared right away. 

Edited April 2, 2023 by jpz

[jpz]

Ok, some additional info to the above message.

I bought a spark plug without a resistor, when touching the plug to the block I get a consistent but very weak spark. So weak, that in order to see it I need to turn off the lights in the garage. In my opinion this is too weak of a spark to run the engine. Of course, I had no reason to check the spark before on a running engine so I am assuming this is a weak spark. Could this be all the more ignition this thing needs?

I pulled the carburetor and it was pretty clean inside. No restrictions, no gumming of old gas. Needle and jets look good.

I installed the carb back on the bike, and even with starting fluid I get nothing from the engine. Just cranking and cranking. No attempt at firing.

I have checked the grounds, and even cleaned them up.

This is brand new battery. When I test the coil remotely with the battery and test leads, I get the same weak spark as I'm seeing when cranking the engine over.

As mentioned above, when installing a car headlight in place of the coil it will make the filament glow slightly, but certainly in not "lighting up" the light bulb.

I tested the ignition unit for resistance (which I believe to be a CDI unit, at least that's how it is listed when shopping for replacement parts), I do not get resistance readings like in the chart for the shop manual.

So all that being said, this seems to me to be an ignition problem, however I can't pin point which item is the bad item. 

When I check resistance on the pulser unit I get readings above what the manual calls for. For the coil, I get readings below what manual calls for. I actually have 2 coils, and both test outside of the shop manuals specs. The ignition unit also tests below the manuals specs.

I really don't want to start throwing parts at this, but I don't know where to go from here.

 

Any thoughts would be greatly appreciated.

[Mech]

It sounds like the spark would be ok once it was running, but I suspect the lower voltage when using the starter is killing the spark. Are you sure your battery is big enough ?

If you jack the back end of the bike up and block it, then reach under a back wheel and pull back and upwards you should be able to spin the engine over when it's in a high gear. You could check how the spark looks doing that, and, you might even be able to start the bike like that. If you can get it to start and run long enough to warm up it might be right.

The description of the headlight bulb in place of the coil sounded a bit strange.. The fact it got brighter as you kept cranking. It might have just been the bulb getting warmed up and so normal, but perhaps you could try putting the same bulb on  the coil's power wire but earth it with a jumper. That will test the 12 supply to the coil. Then with the key on so the unit is powered up, use a jumper from the positive battery terminal to the bulb, and use the ignition unit to earth it as you spin the motor over.  The unit only turns the earth on to the coil for a few milliseconds at a time, so the light should only be dull. The HT(high tension) spark occurs as the earth gets disconnected and the magnetic field in the coil collapses.

[jpz]

I have actually tried using a car battery when bench testing the coil, and the result was the same type of spark that I get now. So I have to assume that the bike battery is good (and it is brand new).

I'm a bit lost with the spinning of the back tire in an attempt to start the bike. Wouldn't that produce the same result as using the pull start? I have done the pull start as well, and get the same result.

As for the headlight in place of the bulb, I wouldn't really say it got "brighter" as I cranked. It only very slightly made the filament glow as I continued to crank it. It was not even enough to produce light, just a slight glow.

When putting the 12v supply of the coil to the battery, and then a jumper to ground the bulb fully lights up when turning the ignition switch on.

The owner of the ATV just told me that when he replaced the battery he "may have" connected the battery backwards. No fuses are blown, but I'm wondering if this could have damaged the ignition unit and be causing the weak spark that I am getting.

It just really makes no sense, and something is causing a weak spark when the ignition system is fully connected. When I bench test the coil alone, I can jump the spark of the proper resistor spark plug when gapped to .7mm. However, when installing the ignition system to the bike, and cranking the engine I cannot jump the spark on the same spark plug unless I reduce the gap to .3mm. So something in the system is causing a weak spark. I have 2 coils, and have tested both with the same results. The battery is brand new, and on a battery tender so it is fully charged.

The pulser unit only controls the timing correct? If so, then I have to assume something in the ignition unit is causing the weak spark? I can't duplicate the test in the manual for the ignition unit due to not having the correct tester they call for. It appears that I would need a multi-meter that produces more voltage than your standard Fluke meter.

Edited April 6, 2023 by jpz

[Gwbarm]

I have been thinking it was the ignition unit also, but I don't like to suggest high dollar parts until im sure, the only thing that still makes me unsure is the ignition unit normally either works or doesnt work, in my experience, it does concern me that your pick up coil and main coil are not up to specs, but If you bench tested the coils and got a good spark, then we are back to either pickup coil or ignition unit.

[jpz]

9 hours ago, Gwbarm said:

I have been thinking it was the ignition unit also, but I don't like to suggest high dollar parts until im sure, the only thing that still makes me unsure is the ignition unit normally either works or doesnt work, in my experience, it does concern me that your pick up coil and main coil are not up to specs, but If you bench tested the coils and got a good spark, then we are back to either pickup coil or ignition unit.

I wouldn't say "good spark" from the coil(s) I have. It is still a small spark, but they are comparable to each other. So, I would assume since both coils produce the same spark when bench tested they are both good.

When you say "pick up coil" are you referring to what the manual calls the pulser? It appears to be connected to the crank on the engine going off the shop manual photos. Or are you referring to primary and secondary sides of the coil?

I agree with your statement of ignition units either "work or don't work". That has been my experience also. However what is really driving me nuts is when I bench test the coil, using the correct resistor plug that is correctly gapped I can jump that gap with what I would call a weak spark. When I connect everything back to the bike, and crank it over I can not jump the same gap on the same plug. I need to reduce the gap on the plug to .3mm (half factory spec) to jump the gap. Also, for some clarity when I say weak spark I would compare it to the spark I see on my 2 cycle engines. No where near the same spark that I see on my snow blower (208cc 4 cycle). I have never looked at the MXU spark when it is running correctly so I can't say if this is a good spark or weak spark for this machine. 

Reading the shop manual, it speaks of condensers in the ignition unit, which I assume function like a capacitor and help during start up. Also, now knowing that the owner possibly connected the battery backwards I'm assuming something was cooked in the ignition unit.

I hate to just throw parts at anything too, but I'm not able to find a smoking gun other than comparing the bench test of the coil, to the fully installed ignition assembly on the bike.

[Gwbarm]

The pickup coil and pulser coil is the same, under the stator cover the small coil that generates voltage for spark as the rotor goes around, you said you have condensers(small capacitors) are they internal or replaceable external.

[jpz]

The condensers I mentioned were described as being part of the ignition unit, not the pulser. That was the other reason I was thinking ignition unit over pulser. I was under the impression the pulser just controlled the spark timing.

The only test I performed on the pulser was to check resistance which was 120 ohms. The shop manual said it should be 105-110 ohms. I was thinking similar to the coil, (which tested slightly off) 120 ohms was not enough of an issue to cause my problem.

[Mech]

Your coils don't sound good to me. Their resistance is too low, which means they draw more current than they should, and they don't produce a good spark on the bench test.

The ignition unit will likely have several capacitors in it, one of which could be connected from the coil's negative to earth in the same manner as in old points systems. There will probably be other capacitors used in the timing advance, and dwell calculations. The Kawasaki manual warns against disconnecting the battery while the engine is running, or putting the battery in backwards as it may cause IC damage. IC stands for integrated circuit. If it's had the battery in backwards then it could be the unit. But then I'd expect you'd get no spark at all.

[jpz]

This is where I'm struggling. I have 2 coils. 1 came with the bike, 1 I bought because the factory coil tested outside the factory manual specs. 

Both have similar resistance readings, and both test identical on the bike and on the bench. That's why I started leaving towards the ignition unit.

I'm having a hard time because typically ignitions work or don't work. Where this one is working poorly.

Does the pulser unit in any way factor into the current for the ignition? Or is it solely for timing?

 

[Mech]

No the pulse coil just triggers the ignition to fire. It doesn't effect the current through the coil other than turning it on and off.  It does set the timing.. If it wasn't working you'd get no spark at all.

There's a chance the ignition unit might be damaged, and not putting power through the coil for long enough, or with enough current, or not cutting it off cleanly as it should at the instant it fires the spark, but it doesn't seem likely if you get some spark out of these low resistance, poor spark, coils.

If you can't get a good spark on the bench with 12 volts, don't expect the bike to perform some miracle and make then throw big strong sparks..  It's not a cdi and it's not going to do it.

[jpz]

My struggle is I have 2 coils and both function exactly the same.

I unfortunately have no idea what a "good spark" is supposed to look like on this bike since I only have it to hopefully fix it.

If the pulser is only for timing, and I have already replaced the coil with the same end result I'm stuck with not many options.

Definitely a frustrating bike so far.

[Gwbarm]

Im thinking you may have to get an OEM coil just to make sure you have the right one, I say this because I ordered 3 aftermarket before I got one that was close to the right specs, still wasn't exact, but I am sparking, not running yet waiting on parts, but if I still have problems running that's what I will do. It still may be your ignition unit, but like Mech says if your not getting a good spark on the bench with direct battery feed something is wrong.

[jpz]

Thanks guys. I'll reach out to my local dealer about a factory coil. 

What a project this has become.

[Gwbarm]

Local dealers are more expensive than online dealers, you might compare prices I use rocky mountain ATV and Motosports. 

[jpz]

On 4/7/2023 at 12:16 PM, Gwbarm said:

Local dealers are more expensive than online dealers, you might compare prices I use rocky mountain ATV and Motosports. 

Ok, so more interesting problems related to this ATV. Hopefully someone has some suggestions. I can't find a quality coil. Rocky Mountain ATV doesn't stock them. I went through a google search and couldn't find anyone that sold the coil. My local dealer no longer services Kymco because "they could never get the parts". I even tried searching for the Kawasaki Brute force, since they seem to be mechanical siblings and no luck.

Any suggestions for where to buy Kymco parts online would be great. I even went to their website, and they still list my local ATV place as a dealer, beyond that the next closest one is an hour drive.

Is Kymco really this difficult to work on/with? Or have I just found the read headed step child in their lineup?

[Gwbarm]

Sorry about that , those are the two that I use the most, I had trouble also finding parts fo Kymco, but thought you might find the Kawasaki one that was comparable. I will keep looking. 

[jpz]

This ATV is going to be the death of me. I may end up calling the dealer that's an hour away and see if they can ship it? Of course, that's assuming they are still a dealer for Kymco. haha.

[Gwbarm]

Found this site seems to have Kymco parts.

https://www.powersportsid.com/atv/kymco-mongoose-270-accessories-parts/

[kp3004x4]

That's what I would CHK also

[jpz]

Well after taking some time off this frustrating project, I'm back on it. I found a dealership that even though they don't service Kymco, they do service Kawasaki. Exercising this grey area, they agreed to test the coil for me. haha.

The coil tested fine, and apparently was able to jump a 8mm gap on their tester.

The service guy was very helpful after testing the coil, and expressed that they have seen a number of these (Bruteforce) ATV's have a bad stator or pulser early on in their life.

So that's my next angle, I'm going through the process outlined in the shop manual I have (Mongoose 250) for testing the stator. If anyone has an actual section from the MXU 270 or Bruteforce 300 that covers the pulser I would be forever indebted to you if you could post it.

Also, any tips or suggestions on the stator would also be appreciated.

 

 

 

[jpz]

I'm back again, working on this quad.

First the good, it is now running and idling great. Starts every time, idles forever.  I ended up working with the above mentioned dealer, and we agreed the most likely problem was the ignition unit. I ordered one from Kymco, and it took practically 2 months to arrive.

Once installed, and quad immediately started. However it would not run unless the choke lever was held closed or partially closed. If I tried to rev the engine, it immediately died.

I took the carb back off, and cleaned it again this time soaking all the parts overnight. Once installed, it started much easier and idled great. However it still stalls if revving the engine above 1/4 throttle.

I removed the spark arrestor, but still have the same result.

I'm going to check the spark plug, and remove the fuel filter. Beyond that I'm stumped as the idle/air adjustment screw is blocked off from the factory. I'm sure I could remove the cover and adjust it but this was a running quad so I'm hesitant to think it needs a carb adjustment.

Any suggestions from the forums? Really been killing myself with this thing and hoping some fresh eyes will have an idea I'm overlooking.

 

Thanks,

[Mech]

It idles so it won't be the idle jet.

Does it die as soon as you open the throttle to 1/4, or does it start to rev and then die after a few seconds ? And it does die right out does it ? The engine stops running ?

At 1/4 throttle the things controlling the fuel are the main jet, the emulsion/discharge tube, and the slide and needle..  Check the short discharge tube(if it has one), which sits on top of the emulsion tube is there, and the right way up. Check the needle is held in the slide.

If it takes a few seconds or more to die out though it could be because the fuel level is going low in the bowl, in which case it could be a blocked filter or float needle jet.

[Gwbarm]

I think I would replace the plug and fuel filter and see if you have adequate fuel flow to the carb. It still sounds like fuel delivery

Sorry Mech I just saw you recent post didn’t mean to repeat what you said

[kp3004x4]

Make sure to CHK float in carburetor to see if hanging up or not set correctly even just fraction of mm sometimes will throw off every thing