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Discussion Starter #1
Hi all,
I have a 1989 TRX300 4x4 which I am having spark issues with. At first I thought it was the ignition coil and have replaced that with a brand new one but still nothing. next step was the CDI. With the spark plug removed I can only get a weak spark when the starter button is first pressed or after I have released it, there is nothing whilst it is cranking. I have now replaced the cdi with a known good one I have borrowed but I now have no spark at all. Can anyone shed any light on this for me
cheers
 

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Replace the alternator stator. The single spark you get when pressing or releasing the starter button is caused by a false trigger of the CDI due to a voltage surge that happens when the starter first starts drawing current and/or when the button is released and the starter motor stops drawing current.
 

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Discussion Starter #4
ok guys I have replaced everything I can think of so far on this and still nothing. the only difference is when I put the replacement cdi in I have no spark at all and when I put the original back in I have very weak/intermittent spark again! the replacement cdi is a borrowed one out of a friends bike that we no works, only difference is his is a 1991 and mines an 88. could this be an issue?
 

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The CDI units are different. The 1988 model TRX300 2 and 4WD used part #30410-HC4-003. The 1989 thru 1993 2 and 4WD used part #30410-HC4-770. The parts look the same and will plug into the wiring harness, but they are different even though they cost the same.

The part you need to replace is the alternator stator inside the engine. There were two different ones used. One with 12 winding's and one with 18 winding's. Either one can be used, but if you are changing from a 12 to 18 (or vice versa) you have to change the rotor also.

The cost for the winding from Honda only is $260 and $262 respectively and is the same for 1988 to 2000 for the TRX300 and the TRX300FW.
 

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Discussion Starter #6
yea ive replaced both the stator and the pickup coil without any luck. now that I no that the cdi is different il try getting the correct one
thanks heaps for your help
 

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well guys still no luck. I have replaced the cdi with a known good one out of the same model bike and still got nothing. I have checked all wiring with a meter and all voltages and resistances are all within spec of what the manual says. the only difference is now I have absolutely no spark at all with either cdi units. the only thing I havnt replaced yet is the regulator/rectifier which I wouldn't have thought could cause the problem. or could I be wrong?
 

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No - the rectifier/regulator only has to do with charging the battery. You can test the rec/reg by simply disconnecting it.

Last suggestion - disconnect the main switch (key switch) from the wiring harness. Check for 12v on the pink wire with the white stripe at the harness side of the connector. If you don't have 12v on that wire, check the connections and the fuse in the pink/white wire near the battery. If you have 12v at the connector, use jumper wires to connect the red to black wire and connect the pink/white wire to the pink wire - see if you have spark - if yes, bad main switch or bad connection on main switch. The main switch is the same for 88 and 89 TRX300 and 88 TRX300FW models.

If no spark, connect the red, black and pink wires together - if spark, bad connection causing lack of current flow on pink/white wire. Unplug the CDI and check for voltage on the pink wire at the connector. With the connector plugged into the CDI unit, pierce the pink at the CDI connector wire with a straight pin and run a jumper wire to the positive side of the battery - check for spark. When you turn the switch on; it connects the red to black wire and the pink/white to pink wire.

Hopefully somewhere in this process, you checked the spark plug cap and are using a new spark plug.

NOTE: a wire can have voltage without a load on it (voltage is potential or push) - current is amperage (flow). A bad connection will restrict the flow. Imagine a garden hose with a kink in it. There is pressure at the nozzle (voltage), but when you open the nozzle, you get a burst of water that slows to a drip (amperage). Remove the kink (repair the bad connection) and you get constant flow. A bad connection may be a wire that is broken inside the insulation (kink). A problem like that is one of the hardest to find.

I have encountered bad wires and to find them I had to create a "cheater harness" that connected just the key components of the problem system and eliminate them one at a time.

I hope this helps - it is so much easier to have hands on it than to just try to guide blindly.
 

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Discussion Starter #9
ok this is what I have found. there are 5 wires at the ignition switch connecter(switch end) red, black, 2 pink and a pink and white. the pink and white one was disconnected. when I connect it to the harness end which is also pink and white, and has 12v coming out of it, the glass 15a fuse at the battery blows. is this wire supposed to be connected?
 

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I am about to order a new CDI unit for my 88 TRX300 4x4. I am not getting a spark and I have tested all the wiring etc to the best of my ability so a CDI is my next option. When ordering from some websites I see the options "FourTrax 300 4x4 TRXFW" and "FourTrax 300 TRX300". Am I correct to assume the "TRX300" version is just the 2 wheel drive?


Honestly not trying to ask a stupid question...I just see the word "FourTrax" and begin to think that means 4x4 itself.
 

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Sounds like a Ignition Pulsar Coil. Also known as a a, Pulse Generator, Pick Up Coil, Pulsar coil.
 

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Right the TRX300 is 2WD and the TRX300FW is 4WD - the good news is the CDI ubit is the same for both - the bad news is (according to my sources) the unit (Honda part number 30410-HC4-003) was only used on the 1988 model 300 & 300FW
 

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Right the TRX300 is 2WD and the TRX300FW is 4WD - the good news is the CDI ubit is the same for both - the bad news is (according to my sources) the unit (Honda part number 30410-HC4-003) was only used on the 1988 model 300 & 300FW
Why is it bad news that it was only used on the 1988 models?
 

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Makes finding a used one more difficult - less likely an aftermarket manufacturer will supply something for a one year production model - the supply from Honda will be depleted and discontinued for a model more than 10 years old
 

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Thanks for the info. I put my new CDI on today and immediately got a spark back. The four-wheeler started right up after that. All is well.
 

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[B]Bad Voltage regulator can affect the ignition and cause a no spark condition.[/B]

No - the rectifier/regulator only has to do with charging the battery. You can test the rec/reg by simply disconnecting it.


My 2000 TRX450ES wouldn't spark, and the problem was the Regulator/ rectifier. I had trigger voltage coming to the CDI, 12v, ground, etc. but didn't have any voltage going to the coil primary.
I disconnected the regulator/rectifier, and it wouldn't spark.

Replaced the CDI, but that didn't fix it.
Replaced the Voltage regulator, and fixed my problem.
I even installed the Old CDI after replacing the regulator and it worked.

Bad Voltage regulator can affect the ignition and cause a no spark condition.
 

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I am eager to learn. I need to find out how the voltage regulator had an effect on the ignition. I do not have a 450ES to experiment with at the moment. Could you post the Honda part number of the part you installed to get spark?
 

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How can the Rectifier / Voltage Regulator affect Spark

The answer to your question is one the three leads from the Stator is wired in Parallel with the voltage regulator and the CDI (this is the link between the CDI and the Voltage regulator).

Apparently, at least one of the Diodes in my Regulator / Rectifier is bad affecting the AC current from the stator which feeds the CDI. This is how the Voltage regulator can affect the ignition system. (I did get some different readings between the 3 terminals on the voltage regulator that the stator leads connect to which would have led me to the bad regulator). The Honda Factory Service Manual does not indicate that the Voltage Regulator should be tested, nor do they provide any instruction on testing the Voltage Regulator on a non running engine (diode testing).

If you look at the wiring diagram and follow the stator leads, you'll notice the connection which goes to the CDI from this single stator lead between the stator and the Voltage Regulator.

There is a way to test the voltage regulator diodes (I've seen some posts about it), but I'm not certain that it is absolutely fool proof. And it is truly annoying when someone is asking for help with a no spark condition and guys post about testing the voltage regulator with the engine running... It's not running. That's why they are asking for help...

I never had a problem with the battery charging on this ATV, even when it started acting up. It would run sometimes, sometimes not. But the battery was always fine which would lead you to believe there is no reason to suspect the voltage regulator...

I just wanted to put this information out so that others that have this No Spark problem will hopefully see this which could speed their diagnosis and repair.

The dealerships have the advantage of being able to just plug in a new CDI and Voltage Regulator which only takes a few minutes to determine which is a problem as opposed to having to check every connection, ground, quick connector, and every device that can be tested with a multimeter before buying a replacement part.

If you have a no spark condition and everything tests good, and you've replaced the CDI, DON'T OVERLOOK THE VOLTAGE REGULATOR. IT CAN AFFECT YOUR IGNITION SYSTEM AND CAUSE A NO SPARK CONDITION.

Just Google testing your voltage regulator diodes Honda ATV TRX, and hopefully you'll find some instructions which can be done with a multimeter that has a diode test function.


https://www.google.com/search?client=safari&rls=en&q=honda+trx+voltage+regulator+diode+test&ie=UTF-8&oe=UTF-8
 

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Thank you. This is excellent information!

I studied the wiring diagram (drawing number 0030Z-HN0-A100) - I believe a rectifier/regulator failure that affects the ignition is a rare circumstance and can be tested by simply disconnecting the rectifier/regulator and attempting to start the engine.

If you would, disconnect the r/r and see if the engine will start. I believe it will, but there will be no charge going to the battery. If I am correct, someone whose vehicle suddenly loses spark might be able to unplug the r/r and "limp home" (as long as the battery has a sufficient charge).

This could be a test that service departments want to add to their manuals.
 

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At least in my case, disconnecting the regulator did not resolve my no spark problem. With the regulator disconnected, my ignition system would not spark.

When you have a bad voltage regulator and you've only worked on one atv and it had a bad one, it's not rare. In my case, it was 100 percent of the time. I think that most people would be surprised that the regulator can kill your ignition spark.
 
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