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TRX300 no or weak spark

141227 Views 49 Replies 10 Participants Last post by  bobuphd883
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
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Great thread. Registered here because I've been searching for answers and this was the most informative place I found out there.

I don't currently have a quad myself, but my buddy has a '96 300 Fourtrax 2x4 that he's been having problems with. He's had a few people look at it and nothing, so he asked me to have a go.

No spark at all. So far I've tested all the wiring for both power and resistance (where applicable), replaced the coil and plug wire (new) and CDI box (also new), neutral safety switch, and of course the plug. Nothing. Only things I haven't replaced are the stator and regulator, stators are expensive just for a test.

Power to (and past) the ignition switch, neutral light on, oil light pops on for a few seconds, starter works fine.

I even put a meter on the hot coil wire while I cranked it, and seem to only be getting a peak 0.03-0.04 volts on pulse. After reading this thread I also tried unplugging the regulator and spun it over - nothing.

No spark at all at any point, not even a weak one. It would seem after reading this thread that there isn't much left I can try except replacing the regulator and/or stator, but at this point replacing more parts as a test doesn't seem like the best idea, and I don't have another unit to borrow parts from. Just wondered if anyone might have any thoughts on any more testing I could do without more parts swapping.

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If I haven't revealed this before - a friend of mine had a 200, tested everything by the book, the only part that tested good was the stator, alas - the only part that was bad was the stator which tested good.
That would figure, wouldn't it? :D

The rectifier can be definitively tested with a meter - if it ohms out, then it's either the wiring, the stator, the flywheel magnet or something else kinda off the wall.
Appreciate that, Here 2 help. I didn't want to have to crack the case, but I guess that will be the next step after seeing how the rec tests out. I really miss the old days - check the points, check the coil, go riding. :p

I'll update if I find anything...
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