KDXRIDER.NET

Well, I hope someone can answer correctly some of the questions I lay out in here… but if not, at least someone can benefit from this experience… so here it goes:
I have a 2002 Kawasaki KDX220R that started to give problems. First it started losing a lot of the coolant from the overflow tank but I couldn’t tell whether it was overheating or not as it didn’t evaporate the coolant and lately, every time I took it out for a ride; after a couple of hours of use it started to: (a) run rough (like misfiring), then (b) shutting-off repeatedly, and finally (c) it won’t start. So back at home I checked the spark plug, carburetor, air filter… cleaned them, etc. Took the bike out next time… and same story. Finally on my fourth cycle of this… no spark!

And the saga begins… with the help of the previous owner/friend we pulled (i) the stator, (ii) spark-plug-cap, and (iii) the ignition coil out of the bike and - due to the lack of a service manual and immediate advice – dropped them to an electronic shop for they to let us know whether those where ok. However, we didn’t even knew the resistance (ohms) they should have. At the shop they said the stator was ok, but that the ignition coil and cap were toasted. Checked all connectors and cables and they are good. Then I phoned “literally” every single motorcycle shop in the city, plus the three closest cities as well. Parts (either ignition coil, spark plug cap or others) will take 3 weeks to get here. I order the OEM Ignition coil (as apparently that was the trouble). Just FYI, it’s been 4 weeks and the shop say is on back order

Anyhow, I managed to get (i) the electrical section of service manual (thanks to an unknown guy but I still hope to find the entire service-manual somewhere), (ii) a “generic” ignition coil, and (iii) a spark-plug-cap - that seems to match well the spark plug. Apparently any ignition coil as long as it’s grounded to the bike… should/could work. It seems there’s really no clarity about this (???).

Based on the service manual I checked the resistance (primary and secondary) of the ignition coil. The manual says they should be: Primary= 0.16 to 024 Ohms (at 1 Ohm scale) and Secondary= 5.0 to 7.6 (at 1k Ohm scale) – read 5,000 to 7600 Ohms. What I got from the “Generic Ignition Coil” was: Primary= 0.16 Ohms and Secondary= Nothing… Zero, “nada” (???).

Then I went and tested the original CDI unit and the results I got were hit and miss. Some as the specs, some quite different (e.g. infinite when zero or vice versa) and some constant Ohms readings of about 0.35... most likely a Multimeter reading issue.

In the interim of waiting for parts to arrive and regardless of the readings on the “generic ignition coil” I installed it with the existing CDI unit and the generic spark-plug-cap and… Voilà!... the bike started, every time; however, it runs very rough (again, like ignition misfiring).

On my fear that the CDI unit is giving troubles as well, I ordered one + an extra ignition coil from the fellows at regulatorrectifier (http://www.regulatorrectifier.com/catalog ) nice people!. They are way, way cheaper (IC=$40 + CDI=$70) instead of $80 +$450 respectively for OEM parts through dealerships and apparently plug-n-play OEM equivalents (?).I’m still awaiting for the order to arrive. As noted above, I’m still awaiting as well for the OEM-Ign.-Coil from the dealership.

My plan is replace the existing CDI and replace the Ign.-Coil with the OEM (more expensive one) + replace the spark-plug-cap with the OEM which I just got today. I will end up with one additional Ign.-Coil as a spare… and probably donate the generic one (it was $30) to whomever.

Now, questions:
1. Do the different readings in the CDI unit really make a difference and if so… how?
2. How come the Ign.-Coil performance is measured by Ohms, however voltage/amperage/frequency output are disregarded?
3. Different multimeters (digital/analog) give different readings on any of the components… this thing is literally all over the map… so, what device is the 100% right one to be used for testing these components and who has it?
4. Where are the experts about dirt bike electric ignition systems (for older bikes though)?
5. Who can explain this accurately, correctly and on solid ground rather than trial/error or guessing?

Thanks!

Wow, that's a loaded post. You've done a lot of guesswork there, and nothing has panned out. Before we get started on a point to point, what is the condition of the engine, minus the ignition system? Compression test and leakdown test results? Is this running the factory top end? Are we sure about compression and fuel?

Well Julien, you're right! It's been a lot of guessing work on that Ignition system. To the best of my knowledge engine is pretty good. It does has very low hours on it (I knew it before getting it from the previous owner) and the fuel is always been Shell premium mixed 50:1 with Bel Ray. No formal compression/leakdown test... but you can feel it I'd say (?). Apparently when it got hot it start giving troubles and apparently that happens with Ign.-Coils.
Any thoughts?

Yeah, the coil can sometimes start acting up when it gets hot. I'd still say compression test first. If that piston is stock, it needs to come out ASAP anyway.

1. Do the different readings in the CDI unit really make a difference and if so… how?
I think it's bogus to expect to know anything by putting an ohmmeter on the CDI because the CDI has resistors, capacitors, and diodes.

2. How come the Ign.-Coil performance is measured by Ohms, however voltage/amperage/frequency output are disregarded?
The input/output voltage spikes happen in an extremely short moment of time which makes them nearly impossible to measure.

3. Different multimeters (digital/analog) give different readings on any of the components… this thing is literally all over the map… so, what device is the 100% right one to be used for testing these components and who has it?
Measure the output voltage from the stator coil and disconnect the high voltage ignition coil from the CDI and hold it's output wires in your hand and then slowly increase the speed of kicking the engine over till you feel a little shock. (do that with the spark plug removed) If no shock then it's bad. There is a chance it is "compromised" though if you get a shock so the test is not 100%.
4. Where are the experts about dirt bike electric ignition systems (for older bikes though)?
Here I am.
5. Who can explain this accurately, correctly and on solid ground rather than trial/error or guessing?
Click on my signature link to read about ignition systems.

Julien: I'm just wondering... why to replace the stock piston soon if the bike has low km and compression?... is that just in case compression is bad?

Jaguar: Thanks a lot for answering those questions... I'll be heading to your website pretty soon to read about it

I hope to get the parts before the weekend and try them on... if not then is one more week of good weather missed

Thanks again guys !

Jaguar: Quite a good reading at your site !... thanks a lot. So this is what I've done based on it:
1. I disconnected spark plug and CDI
2. Measured the Ohms between the exciter (R-W cable) and Black cable (ground cable?) and it was within specs
3. Measured the AC-volts between them as well and it was a bit higher than 30amps.
4. Based on the Service Manual I checked the resistance between the exciter cable and the bike frame. The manual says it should read infinitive; otherwise, there's a short and it needs replacing. My reading was not infinite

At first I though the problem was the Ignition-coil and that the stator was ok based on the information from the electronic-shop guys. I ordered the CDI and Ign.-coil as fear the CDI may be toasted too (the Ign.Coil reads were bad)... now however everything seems to be reading "something" different than what it should.

Q1. Is that typically how these systems fail or is this sequence and symptoms weird?
Q2. If I do not replace the exciter coil and install the CDI and Ignition coil... can they be damaged by the exciter coil?
Q3. Can all three be damaged?... is that normal failure?
Q4. Can turning-on (starting ) the bike by rolling it down hill instead of a kick cause this problem?

I'd like to avoid unnecessary costs as I do run very low on cash... so what's the best strategy here?
(a) try each part separate, or
(b) change all of them to avoid the getting a good part damaged (if possible)?

Thanks !

tell me exactly what the manual says in regards to the resistance between the exciter wire and frame. I assume by exciter you mean the non-ground wire going from stator to CDI.

Q1. Is that typically how these systems fail or is this sequence and symptoms weird?
often one item kills another.

Q2. If I do not replace the exciter coil and install the CDI and Ignition coil... can they be damaged by the exciter coil?
let's figure out this issue of exciter to frame resistance first.

Q3. Can all three be damaged?... is that normal failure?
yes all 3 can be damaged. best to proceed with caution.
Q4. Can turning-on (starting ) the bike by rolling it down hill instead of a kick cause this problem?

To answer the question you posed to Julien, the KDX 220 is notorious for having stock piston failures. There are many threads on this site describing this issue.

When the piston fails, it will happen without warning, and then you are looking at MAJOR damage. The PO of mine had this happen, and ended up having to install a whole new top end including cylinder along with new crank cases.

This piston failure is not a problem with aftermarket forged pistons, so it is recommended to change it out and be safe now rather than wait and be sorry later.

Q4. Can turning-on (starting ) the bike by rolling it down hill instead of a kick cause this problem?

no

Hi Jaguar,
Thanks again and apologies for my late reply... life just cough up with me. I'll explain, the service manual reads as follow:
Exciter Coil Inspection
-Remove the right side cover
-Disconnect the magneto connector
-Connect the hand tester
Exciter Coil Winding Resistance:
Connections: W/R - BK
Reading: 250~370 Ohms (x 100 Ohms)
- If there is more resistance than the specified value, the coil has an open lead and must be replaced. Much less than this resistance means the coil is shorted, and must be replaced.
- Using the highest resistance range of the hand tester, measure the resistance between the exciter coil lead terminals and chassis ground.
- Any hand tester reading less than infinity indicates a short, necessitating replacement of the stator.

In my case the reading was "zero"... so I guess it is shorted. I ordered the exciter coil which is the one going to the CDI as you mentioned (hope that fixes it if replaced?). The other coil inside the stator is the lighting coil.

... by the way, I only ordered the exciter coil and not the entire stator just because I didn't find a decent price for it... and hope the exciter coil replacement takes care of it... because what else can be damaged in the stator body ?