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Short problem? Blown CDI

29K views 104 replies 6 participants last post by  retro 
#1 ·
Hey, I have a '06 Honda Recon TRX250TM, and I have a feeling there's a short somewhere.
Both headlights are burnt out and completely black on the inside (looks like a short?)
The taillight doesn't work, and I have a feeling it's also shorted, even after I cleaned up the connector with CRC and di-electric grease.
The CDI is dead and I assume it's also from a short.
This all started after I had a no spark, and after looking more and more into this thing it's starting to seem like there is a bad connection somewhere or a short that is causing all these problems.
I took apart every connector and ground on the front end and cleaned them with CRC "Lectra-Motive" Electric Parts Cleaner, blew out the connection with air (cleaned up pretty good!) then took some di-electric grease and coated the outside of the female connectors with it, and a little on the male connectors just to help with water and dirt buildup.
My hypothesis (lol nerd) is that a short or bad connection somewhere off of the reg-rec is touching or acting up after a short amount of time of riding. Because the quad just died one time and never started again months ago, but all the light connectors still send 12v (never checked the tail light tho) and the CDI does get power. So I think that either when it gets warm, or when connectors get jiggled while riding it shorts everything.
I'm going to take apart the pulse coil connector and the stator connector and clean them and see if I find anything funny. Anybody have any ideas on what I could do, or what I should look for specifically?

Thanks everyone.

P.S. Sorry if this post is very un-organized, my brain doesn't work very organized lol
 
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#2 ·
Good on you for inspecting and cleaning the connectors; you’re right for calling out the need for an organized approach.

Start first by getting the manual and schematic. Inspect your fuses and cable attach points. Was your battery installed backward? Do you have any loose cables?

Does your key fit like it should or is it sloppy in the ignition switch? Or do you use a screwdriver?

Find the manual in my link below
 
#3 · (Edited)
I'm already a couple steps on top of that. I've been using my service manual pretty much for everything. The only fuse I can find is the main 15 amp fuse and it's good. Cable attach points? Like connectors? And I'm not sure about the battery. I got it and it was dead so I bought a brand new AGM superstart battery and it's worked fine, never installed backwards. The old one could have been installed backwards, but I doubt that is how everything got shorted. And I don't know what would qualify for loose cables. The ignition switch works fine, and is a little wiggly, but not anything bad I don't think, but I have never used a screw driver on it. Earlier I finished inspecting and cleaning all the connectors (that i could find) which includes: everything in the front like headlights, ign switch, handlebar switches, brake light switches, etc. I also cleaned the only connectors I found in the back which were the pulse coil connector, stator connector, and the two individual reverse and neutral switch cables. I also took off the reg/rec connector and it looked the best out of everything else on this thing, making me think it could have been replaced not too long ago. I just left the taillight disconnected as I've heard horror stories of the taillight shorting out CDIs. That's all I have cleaned/found. I also looked at the connectors in the battery box and they seem fine... also there was a group of things completely taped up in blue electrical tape, and I took off the tape and there was a diode, as well as two individual cables, just like the reverse and neutral cables.... is this for accessories and sprayers? and why would they be taped up? Are there any more cables or connectors I should look at?
Thanks for the response!
 
#4 ·
The two connectors you found taped up in blue are probably circuit test (or accessory) connectors. The diode you found should be tested and put back because it protects the CDI by blocking flyback voltages from the solenoid as it releases.

You didn't mention anything about why or when the headlights blew out. Did that happen about the same time as you lost spark?

Are any parts on the bike cheap china? Reason being, a china regulator/rectifier might have failed and blown up the headlight bulbs, tail light bulb and possibly the indicator lights on the dash. It could fry the CDI as well if voltage ever reached it. Make sure the CDI is OEM too. China CDIs are all garbage like their reg/rects are.
 

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#6 ·
Update! I think I found what is causing the short.
The tail light assembly has been broken for awhile and rust got up in the LEDs and it looks rough. The LEDs don't work, and they don't short (tested continuity). The connector from the controls are sending 12v on the brake light wire, and the brake light wire for when your headlights are on.
I'm guessing it shorted sometime while riding from the rust and blew things up? I'll attach a couple pictures of my findings.
All parts are OEM, and will stay that way. I also figured out what the diode was and I figured out the leads must be accessory leads, they kick out 12v when the ignition is turned on. I'll test the diode right now and update what happened.

I'm ordering a ton of new OEM parts from rocky mountain tonight, so let me know if there is something else I should get if anybody has an idea.
 

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#7 ·
Just an FYI...

The ignition system on your bike is an AC-CDI system. So the ignition is independent from DC battery voltage, it works off from AC power generated by the exciter windings in the stator and is triggered by the pulse generator. You need the ignition switch, the kill switch, the CDI, the exciter coil, pulse generator, ignition coil, sparkplug and the neutral light switch working to get spark. And thats all... Battery voltage plays no part in the ignition. The ignition switch and the kill switch must be OEM part numbers original to the bike, as they work differently than those on a DC ignition system.
 
#8 ·
Alright... that's true. What could be the problem then? Could it just be a rogue coincidence that something over volted in the AC system, or could somehow the two issues (burnt CDI and the burnt headlights) be caused from the same thing? I'm ordering a new diode just to be safe. I got 500 ohms on one side and nothing on the other.
 
#9 ·
The diode should conduct in one direction but not the other. So to test it connect your ohm meter leads to it and check for continuity, then swap your leads on the diode terminals and check again. It should allow current to flow in one direction only. It behaves like an electric check-valve during the test.

Your headlights probably burned out because the voltage spiked too high. That might have been caused by running the bike without a battery in it, or with a bad battery in it, or dirty/loose battery cables and/or ground cable. A bad regulator/rectifier can spike the voltage as well. You can test the charging voltage after you get the ignition fixed and the bike running.

As far as your ignition not working, you'll need to use the service manual to test each component to find where the fault is. If you have any ebay/amazon china parts on it (In your other thread you were buying china parts for this) you'll need to replace those with OEM Honda parts before you can expect it to run. Start your testing with the ignition switch and kill switch, make sure the neutral light switch works, put a new properly gapped NGK spark plug in it, check the ignition coil, exciter coil, pulse generator etc.

If you have a hacked up, spliced, or damaged wiring harness on it, replace it before you waste any more time on testing stuff.

Keep us posted on your progress...
 

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#10 ·
Sounds like the diode is good to me , when it is good , if you connect a ohm meter one way you will show continuity and reverse the leads and it should show nothing , a diode lets the voltage go one way only

the voltage regulator does two things , it converts AC to DC power and it controls the amount of DC power to the bike , put a meter on the battery with the engine running , check the voltage , then rev the engine and continue checking the voltage if it goes over 14.5 then it is bad
 
#14 ·
The battery that was in it when the headlights blew was an old battery, and died after I got it, so that's why i bought a new AGM battery. I have ZERO china parts on this thing, all OEM. The Chinese part I bought mentioned above was from when I was desperate and lazy so I bought a cheap part to see if it would fix the problem, but I will not use it.

Here's a list of what I've done so far so that we are all on the same page:
Installed new NGK plug
Cleaned, blew out with air, and greased ALL connectors
Disconnected taillight assembly and wire due to clogged dirt and other crap
Tested neutral safety switch, reverse switch (wire right next to neutral switch), kill switch, starter switch, headlight switch, and fog light switch for functionality, and all PASSED.
I "tested" the stator with a multimeter and not a peak voltage meter, and it put out about 14v in AC.
I also tested the pulse coil and it was spitting some voltage but I can't remember how much.
Cleaned and greased all ground connectors (haven't check all of them for conductivity, only a couple when testing the switches mentioned before... ill check all of them tommorow)

Here's a list of some of the important parts I've ordered yesterday all OEM from rockymountain:
CDI
Ignition Coil
Coil Cap
Starter Diode
2x Headlight bulbs

I haven't hooked up my multi meter to the ignition switch, but I don't see a need. Should I? I don't know what I'd look for lol
The parts might get here Thursday, I'll update if it runs or not, and if it runs, i'll be sure to check the battery voltage while running like you said.

Thanks again everyone for the help.
 
#15 ·
Oh and I cannot confirm that there was voltage going to the CDI, I just thought there was because while starting the engine I was probing the coil connectors and they seemed to spike in voltage (very small jump ~.1v) but I've figured out it was probably just inductive voltage coming from the other wires laying around there, or the connector for the stator, and the test was inconclusive.

Sorry, I didn't see there was a second page to this thread.
 
#16 ·
The server just dumped the reply I typed. So I'll shorten up and just say yeah, check the ignition switch as the manual shows. There are more than one pair of wires to check and one pair will read open. The kill switch should read open in the RUN position too. Only other comments I had were about checking the exciter coil windings as the manual shows. Thanks for keeping us updated!
 
#17 ·
I'll check the switch today, and I can't really test the exciter coil because I'd need a peak voltage tester, which I do not have.... I didn't find anything about checking the resistance... i'll check the manual again.
Does the reg/rec manage the AC power going to the CDI? I'm trying to think what could have caused the over voltage to the CDI.

Thanks for the quick reply!
 
#18 ·
Does the reg/rec manage the AC power going to the CDI? I'm trying to think what could have caused the over voltage to the CDI.
No, the CDI is powered by the exciter coil windings in the stator. Only the alternator charging windings are managed through the regulator/rectifier. The exciter coil is independent from the alternator.

What makes you think the CDI was blown by overvoltage? It cannot be ruined that way unless the wiring harness was hacked on.

You can make your own PVA if you need to. That thread link is here:
https://www.hondaatvforums.net/forums/repair-maintenance/120450-make-your-own-test-adapters.html
 
#19 ·
Thanks for the link, I'll look into it.

As of right now I still don't really know what killed the CDI. It just seemed like over volting or a bad battery caused it, or maybe a short because of the bad taillight all rusted.

The stator has seperate windings? I didn't know that. And I don't think the wiring harness was messed with.

What exactly do I test for?
 
#20 ·
Update:

I ran tests for current leakage, alternator charging coil, and rectifier connector.

The current leakage test showed nothing on my meter, meaning there was no leakage I guess.

The alternator charging coil test was weird. I tested the two yellow wires (all according to the manual) and the resistance was supposed to be 0.1-1.0 ohms, and with my meter's dial set to 200 ohms nothing was picked up. It also said to check continuity between the yellow wires and ground, and once again nothing was picked up. Note that I checked my meter by touching various body parts on the atv with grounding, and it beeped with continuity.
Please also note that I tested all of this while it's 100 degrees outside, if that changes anything.

The rectifier connector test was also interesting. I get about .6-.7 ohms between my two yellow charging lines off of the connector, which is within range, but there is continuity between the wires! It beeps either way no matter what polarity of probe between the yellow wires, but it never did this off of the connector from the charging coil. So why now? With the the ohms in range, but continuity I don't know what this means, as the manual doesn't specify if there should be continuity.
From the red wire to the green wire I get the exact battery voltage. But I get like 11 volts from the red wire to the black wire, if that means anything.
The green wire to a grounding point on the atv have continuity.
Also please note I have not tested regulated voltage as I don't have the atv running yet.

What the deal?
 

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#21 ·
As of right now I still don't really know what killed the CDI. It just seemed like over volting or a bad battery caused it, or maybe a short because of the bad taillight all rusted.
Dad-blame it, quit saying that!!! Why do you believe the CDI is dead? The CDI runs on AC from the exciter coil, not DC battery voltage. The CDI cannot be "overvolted", as you put it. The CDI cannot be affected by a bad battery. The CDI cannot be affected by a shorted tail light circuit. Forget about all that... your CDI might be perfectly fine! THERE IS NO BATTERY VOLTAGE EVER BEING SUPPLIED TO THE IGNITION CIRCUIT.

The stator has seperate windings? I didn't know that. And I don't think the wiring harness was messed with.
Yes, the stator contains the exciter coil windings which supply power for the ignition system only. And has entirely separate alternator windings that supply power for the battery charging system only.

I tested the two yellow wires (all according to the manual) and the resistance was supposed to be 0.1-1.0 ohms, and with my meter's dial set to 200 ohms nothing was picked up. It also said to check continuity between the yellow wires and ground, and once again nothing was picked up. Note that I checked my meter by touching various body parts on the atv with grounding, and it beeped with continuity.
Try turning off the continuity test mode on your meter and move the dial to a lower ohms range setting.

I get about .6-.7 ohms between my two yellow charging lines off of the connector, which is within range, but there is continuity between the wires! It beeps either way no matter what polarity of probe between the yellow wires, but it never did this off of the connector from the charging coil. So why now? With the the ohms in range, but continuity I don't know what this means, as the manual doesn't specify if there should be continuity.
Again, turn that confounded continuity beeper off and read the Ohms of resistance measurement only. You are measuring resistance in a circuit... not trying to detect a short or disprove continuity. Those are two entirely different functions that your meter provides.

You've gotten way off track. Now you are checking the DC battery charging system components rather than the ignition system components. Those two circuits are 100% independent of each other. The ignition is a closed AC-CDI system with no connection to any other circuit on the bike.
 
#22 · (Edited)
I just noticed that the service manual has incorrect information in the kill switch test!!! Use my corrected image attached to this post and start over... test the ignition switch and the kill switch on the handlebar by checking for continuity as shown.

EDIT:
You will be checking for continuity (turn your beeper on) between the Black wire with a White stripe (Bl/W) and the Green wire on BOTH; the ignition switch plug and the kill switch plug. Unplug them both from the main harness for testing.
 

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#23 ·
Sorry about being a knuckle head, I'm not super 100% with a multimeter, and I'm just trying to make sure what I'm doing is correct, and clearly it's not lol. The lowest setting is 200 ohms, which only shows one decimal point. Thanks for clearing up how the ignition system is a closed system.

What should I test on the ignition side? I'll re test the ignition switch and the kill switch as well as the stator connector.

Also I think the ignition switch that is currently installed was a replacement part in the past because it still has a tag with a bar code on the wire, and teh tag is old and dirty.
Again, I'm sorry I'm stupid, I'm trying to just figure this all out as stupid as I am.

Thanks for dealing with my dumbness.
 
#25 ·
Nevermind my humor linksg, its pretty dry. I used to work around a guy many years ago who was always telling jokes. Funny guy... but when others would tease or poke fun at him joking around like guys in the shop do, he'd get quiet and flustered. He'd say "Dad blame-it quit that!" once he'd had enough ribbing and we'd all laugh and get back to our work. He came to mind as I began to type is all... and ain't no one here any dumber 'n me... Hang in there man, and if'n ya get flustered ya know what to say. :)
@fishfiles his bike has an AC-CDI ignition, so high voltage spikes from the charging system can't reach the CDI through the stock wiring harness.
@linksg lets start over from the beginning. The service manual probably messed you up cause the wrong information is published in there for the handlebar kill switch tests. So plug that diode back in that you untaped, plug everything else back in and start with checking the ignition switch and kill switch using the corrected service manual pages I attached above. Then check to make sure the neutral light comes on when its in neutral and goes out when you shift out. Report back here with your findings and we'll go on to the next step.
 
#26 ·
Ah, I see. The wires from that picture submitted don't match my ignitions switch's wires at all, only one matches and that's the black one. I just received all my new parts, should I just install all the old parts and try stuff?

The neutral light and reverse light work, and the engine won't crank unless in neutral. So that's good stuff, and I also check the connectors for them both awhile ago.
 
#27 ·
The ignition switch should have a three-connector plug, plus a single bullet connector plug for a total of four wires. The three-wire plug should have a Black/White wire, a Red wire and a Blue wire. The bullet connector should have a Green wire. If your switch harness has different colored wires and/or does not have two plugs totaling four wires as explained then it is not an OEM ignition switch.

Let us know what ya got before continuing.
 
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