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Discussion Starter #1
Hi All,

I've read many posts on this forum, but nobody seems to have a similar issue to me.

I have a 2003 400ex that won't start. I've purchased many new parts to try to troubleshoot, and still can't seem to find a cause for my issue

The issue I'm having is that I'm not getting any spark when I use the electric start.

I have the spark plug out of the engine connected to the coil so I can visually see it. When I turn the engine over manually by spinning the rear tires, I see a spark - Great!
But when I use the electric start, it is not sparking.

I can't figure out why it would not produce a spark using the electric start. I thought that perhaps the starter isn't turning it over fast enough to meet the CDIs minimum rpm, but even with a new starter and large battery, it still does not spark.

It only sparks when the engine is turned over manually.

Any help is appreciated! Thanks!
 

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Start first by getting a good multimeter. the money spent on one will save a lot on wasted money spent on expensive parts that aren’t bad. Then download the factory service manual and at the end is a wiring diagram. Start learning how to read it. Then tell me about the rest of the symptoms and conditions. Does the neutral light come on? What about the headlights and taillight? I‘m thinking that your problem may be in the ignition relay, but I would start by looking for any loose or chaffed wires that may be causing you problems. Check all of the plugs and connections. Clean all of them with contact cleaner. Pay particular Attention to the black w/ white stripe wire between the ignition switch and the ignition control module. let me know if that gets you anywhere.
 

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Discussion Starter #3
Thanks for the reply!

I've obtained the factory service manual, and have studied the wiring harness. I've done tests with a multimeter to verify the connections. It is quite possible I've overlooked something, and I hope to be able to pinpoint it.
Unfortunately I received the quad with a modified wiring harness. The wiring harness is intact, but many of the stock components were spliced out. For example, the neutral light and neutral safety switch were removed. There are no tailights, and the headlight has been replaced with an aftermarket assembly.

I've done my best to verify that the modified wiring harness is spliced properly by verifying with the wiring diagram.
 

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Discussion Starter #4 (Edited)
Based on your comment about the black w/ white stripe wire, and looking at the wiring diagram, it appears it acts as a spark kill when grounded. Currently the black w/ white stripe wire is disconnected from the kill switch, and is not grounded.

What makes me confident the wiring is correct is the fact that i can see the spark plug spark when i manually turn the engine over. Only when I use the electric starter it doesn't spark.
 

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Yes, and given that fact, it would lead me to suspect that the one part of the wiring that is different between getting power from the battery vs power from the stator would be the problem. will it actually pop start if you pull it and dump the clutch in gear? Is the ignition switch still there?
 

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Discussion Starter #6
The ignition switch has been spliced out.

Yes, it runs fine when I push start it.

From my understanding, the ignition circuit can produce spark with or without a battery, and is not 'different getting power from the battery vs the stator'.
 
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