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Discussion Starter · #1 ·
ok, I have posted before about my 1985 trx125 not having any spark, to begin with i found that it had very little juice getting to the coil and the same at the plug, I checked another honda and the test light lit up brightly on it. we swapped the coil to mine and had the same results, I am at a loss as to where to go from here, does anyone have any ideas on this? thanks in advance.
 

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No - the stator is the alternator windings under the LH engine cover. The pulse generator is under a cover on the top LH side of the cylinder head. The pulse generator tells the CDI when to fire - the stator generates the power to charge the CDI and get it ready to fire.
 

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Discussion Starter · #5 ·
re-no spark

thanks for the info, upon checking with a test light we found that the stator had good output so we traced the wiring according to the diagram and found good power going into the cdi box, the wire from the cdi to the coil had none, would this indicate a bad cdi or is there something else to check, the pulse generator checked out ok according to the ohmmeter. thanks
 

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It's difficult to troubleshoot without getting my hands on it and normally testing with a light is not an accepted method. At this point I would guess it's either the CDI unit or the stator.

I have a friend who had a Honda service manual for his XR200R. When he lost spark he went by the book and tested everything. In the end, the only part that tested good was the one part that was bad.
 

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Discussion Starter · #10 ·
if the cdi is bad would it be intermittent or is it either good or bad, the reason I ask this is because upon checking for voltage I found that there was spark so I put the spark plug back in and then there was no spark again. any thoughts?
 

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Had an 86 XR600 that had bad CDI that was intermittent in being good or bad; good most of time but frustrating when it decided to go bad. Few taps with handle of screw driver or end of wrench brought it back to life more than a few times untill I found a replacement on fleabay for $35. Was supposed to be for newer model XR600,400 or 250 but it worked fine. Found diagram on thumprtalk how to rewire for older 600. Never had a hitch after that. I have 85 TRX125 engine for project that just went "no fire" on me yesterday. Just had it week, sorting it out before putting it in project bike, took pulse cover off and saw screws were loose, tightened them, now no fire, go figure!:confused:
 

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I had spark issues and ended up buying a new cdi. After it came in, I would only get one spark and then nothing. I went back and checked all parts according to the manual and it all checked out okay but still only one spark. Checked and cleaned all connections using brake cleaner (all I had at the time but works great) and when I put it back together it fired right up. Not really sure what the problem was, but make sure all your connections are clean and tight. Some of mine looked like they had been in the mud pit too long.
 

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hate to bring up an old thread....im new here, whats goin on guys? new to the 4 wheeler scene, not new to the bigger toys (rock crawlers and trucks in general)

but i was given an 85 trx125 with the infamous no spark issue. i got a new carb (old one was dirty and just not worth saving), new coil, new spark plug, new cdi and the pulse generator and alternator are within ohm spec.

im pretty stumped here.

i had an idea that i ran by a 3 wheeler buddy of mine. the "reverse switch" (as stated in the manual) is broken and im currently trying to find a new one. the neutral light works but the reverse light does not. could this be a "kill switch" that wont let the spark plug spark? he said that wasnt a thing on the 85s

ive followed the manual to the T....and the thing still doesnt run.

yes it has oil in it, yes the engine switch is on run and the key is on....im no first timer when it comes to motors....but this honda is really starting to rub me the wrong way
 
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