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Honda trx300ex weird spark

1401 Views 6 Replies 3 Participants Last post by  retro
When I turn it over I get spark once when I press the button and when I let it off. Sometimes it will spark consistently when I pull the plug and hold it against the head. I’ve replaced the: stator, pulse generator, spark plug, coil, and even the CDI. I’m at a loss here. All the grounds have low resistance. All wires are exposed and none are bad. I have ran a jumper from the battery to the power wire to bypass all switches that could fail.
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If the woodruff key was sheared then there would be no exhaust (or very weak), and the starter would almost freewheel. In both cases that’s not what’s happening. Can anyone explain why it sparks when the starter is first engauged and let off? Could there be a significant power draw or something?
A sheared woodruff key would not affect the exhaust or the starter, it would affect the ignition making it fire the plug at the wrong time.

It sounds like your issue is a bad CDI. Is your CDI an (or any other ignition parts) aftermarket one or OEM?
I'm sorry but you are wrong. The woodruff key secures the starter driven gear to the engine crankshaft. If this key was sheared the engine would not turn over. Yes, it would affect the spark of the plug because the flywheel would be spinning while the starter is engaged, but the engine wouldn't even be turning over to fire. I do have some firing just when the starter is engaged and disengaged.
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