TRX300 No spark

[TomJulio]

My 1992 TRX00 recently stopped firing.  I understand this is a common problem. I have ordered an aftermarket CDI unit.    TJ

[TomJulio]

battery and wiring check good. 

[TomJulio]

Spark plug, cap and ignition coil check good.

[TomJulio]

Does anyone know which aftermarket CDI is known to work reliably?   I hear Rick's electronics are pretty good.  

[TomJulio]

1992 TRX300A

[TomJulio]

I have removed the OEM CDI box.  no visible defects.  connectors look good.

I need the specs to read out the magneto coils.

[TomJulio]

Troubleshooting results.  No spark while spinning engine with electric starter.    No spark using the pull starter either.  

Sometimes the red oil temp comes on when I first turn on the key switch.  This should be a bulb check cycle.   However, sometimes there is no red lamp when turn the key on. 

[TomJulio]

Stator output values?   VAC?

[Gtc4d]

I know this sounds dumb, but  my yamaha has a run stop switch on the handle bar which i never use, (I use the key switch) but this has bit me before. i over look it because i never use it but it will keep the coil from firing. after that i would try to find a schematic for the unit. Good Luck.

 

Todd

[TomJulio]

Good copy Todd.   I did check that same switch in the TRX.  It checks good.  

[TomJulio]

A new CDI unit fixed my ignition problem.    I did order a new rubber mount for it too.  Mine is hard as a rock.  This may have contributed to the problem as there is no vibration isolation left on this 34 year old rubber. 

[C2INS]

Yeah CDI seems to be a likely culprit.  Similar happened to me with a 1985 TRX250.  Got a new CDI from Amazon which I think was for an ATC (had to read a few reviews to see if would work on mine), and I was finally able to get spark.

[TomJulio]

Yep.   New aftermarket CDI fixed it.  Runs great now.  

[jen]

Hmmmm...I have my Yamaha SR 500  --Thumper-sitting in storage as the CDI is bad.   I replaced it once.  bad again  Did not know where toget one without Bigg $$$.  Good inspirational thread..

[WeeBee]

Try Dennis Kirk for CDI 

 

[Jdsride]

I've got a 1991 Honda fourtrax 300,2x4, that I'm going thru the same no spark issue. Ran great, started it and walked to garage and back and it had died. Would not start again, no spark. I really dislike wiring and electronics. I need troubleshooting for dummies, lol. I got a new coil and cdi, with no luck. Got power to the black and white wire on two prong plug to cdi, but no power at coil. Checked continuity on the stator plug. I'm getting 1.1 ohms ( if I have setting of multimeter right?) between all three wires to stator. Not sure if that's in tolerance? Anybody able to explain how to test out the wiring and components to a less than adequate electronics guy? I'm a decent shade tree mechanic, and I will figure this out eventually, but may end up buying all new stuff and find out it was something simple. Luckily I have  a Kawasaki prairie 300 that's a good backup, with no issues, yet! Anyway, great to be on forum with you all, thanks, jd 

[Gwbarm]

No power to the coil, new CDI, i would check the continuity of the wire going to the coil. I would also determine which wire  goes to the pickup coil and check the OHMs. Then check to see if it is actually putting out voltage, the voltage is so small i use an anologue meter the needle is so sensitive you can see it move dont blink or you will miss it. If you have a peak voltage adapter for your digital meter that will work or may be built in, if you have a very expensive meter.

[Jdsride]

Thank you Gwbarm, I did just get a new multimeter, better than a cheap harbor freight one, but not sure if it has peak voltage setting, has auto range and all that. I'll have to google what that looks like, or I guess, read the darn instructions. Lol. The pick up coil is in with the stator correct? So has 3 yellow stator wires, then the other plug branching off with stator wires would be for pick up , I'd assume!? I appreciate the pointers, I will give it a shot soon, haven't had much time recently , but anxious to get back on it. Any advice is always appreciated, thank you again!!  Jdsride

[Gwbarm]

That correct the 3 yellow wires for lights and charging and the other plug would be for the pickup coil and it may have an anti rotational direction coil, i call it an anti kickback coil, not sure if yours has that havent looked at a diagram.

[Jdsride]

Am I doing something wrong? Testing the continuity  of stator wires , it's the same reading between each yellow wire, using auto range multimeter. From what I understand, the R x 10 is a moot point with auto range meter, or is there a different setting I need to use? I guess I'm hoping I'm doing something wrong, otherwise I'm changing stator. The test between yellow wire and ground gets nothing, so that's good , nothing in stator grounding out, I assume . Anybody out there can tell me I'm a dummy and doing it wrong, I'll gladly take it , really not looking forward to buying and changing stator, but, will if necessary !? Thanks Jdsride! 

[tepin]

На катушке зажигания 2 провода + и управляющий, который управляется с коммутатора. Если есть статор, тогда речь идёт о генераторе напряжения или о стартере. Что мы ищем? Если на катушке зажигания на одном проводе нет +, тогда надо проверить откуда он идёт. Думаю он будет идти по цепи АКБ-замок зажигания-предохранитель-контакт катушки зажигания, второй провод с катушки зажигания либо в коммутатор, либо на контакты в трамблёре. 

[Jdsride]

I cannot read your language, sorry

[vr32]

5 hours ago, tepin said:

На катушке зажигания 2 провода + и управляющий, который управляется с коммутатора. Если есть статор, тогда речь идёт о генераторе напряжения или о стартере. Что мы ищем? Если на катушке зажигания на одном проводе нет +, тогда надо проверить откуда он идёт. Думаю он будет идти по цепи АКБ-замок зажигания-предохранитель-контакт катушки зажигания, второй провод с катушки зажигания либо в коммутатор, либо на контакты в трамблёре. 

Here's what google translate says:

The ignition coil has two wires: a positive and a control wire, which is controlled by the ignition switch. If there's a stator, then we're talking about the voltage generator or the starter. What are we looking for? If there's no positive on one wire of the ignition coil, then we need to check where it's coming from. I think it'll go along the battery-ignition switch-fuse-ignition coil contact circuit, with the second wire from the ignition coil either going to the ignition switch or to the contacts in the distributor.

[Gwbarm]

This is telling you how to check the main stator which controls lighting and charging, the test you did sounds fine, but it does not mention checking of the pickup coil which controls your spark. Not sure of the wire colors but it would be the other plug your service manual would tell you the correct resistances for that. If it is bad it cannot be replaced without replacing the whole stator. If it tests good then the coil is OK but sometimes trash and debris gets between the coil and the rotor to keep it from functioning properly, but there also could be other electrical problems.

[tepin]

7 hours ago, Jdsride said:

Я не понимаю ваш язык, извините

There are 2 wires on the ignition coil: + and the control wire, which is controlled by the switch. If there is a stator, then it is a voltage generator or a starter. What are we looking for? If there is no plus on one of the wires of the ignition coil, then we need to check where it comes from. I think it goes through the following circuit: battery — ignition switch — fuse — ignition coil contact, and the second wire from the ignition coil goes either to the switch or to the contacts in the distributor.

[Jdsride]

On 5/14/2026 at 12:12 PM, Gwbarm said:

This is telling you how to check the main stator which controls lighting and charging, the test you did sounds fine, but it does not mention checking of the pickup coil which controls your spark. Not sure of the wire colors but it would be the other plug your service manual would tell you the correct resistances for that. If it is bad it cannot be replaced without replacing the whole stator. If it tests good then the coil is OK but sometimes trash and debris gets between the coil and the rotor to keep it from functioning properly, but there also could be other electrical problems.

The pick up coil seems to test out fine, it has yellow green and blue wire. The yellow taps into yellow one of the stator yellows. I'm just confused on stator readings, they are really high, out of tolerance, but a lot of videos say if they are all the same number, it's fine ??? Prob just going to change stator, I've removed it already, tryed testing Direct to stator, no connector or wires in between, still high reading.

[Gwbarm]

I agree, if you have it out i would go ahead and change it especially if you have erratic readings.

[tepin]

There may be a short circuit or a breakdown under voltage. I think replacing it with a known good one would be the best solution.