I had a customer bring in his 06 400 auto 4x4 to me yesterday. he said its been parked for a year and won't start. Before that, it wouldn't go over ~8mph and then would die.

I pulled it in, did some trouble shooting, and there was no spark. I narrowed it down to a bad coil, but I can't shake the feeling that there's something else causing the lagging. I don't have a peak voltage reading adapter so I can't test the input voltage to the coil. Are there some tests I should run to test the stator? Rectifier/regulator? CDI?

I have the service manual and it's about as much help as a rubber crutch in a polio ward, especially since there's no wiring schematic.

 

The 2003-2006 400's had a problem with the magnets coming loose from the stator. I lucked out, my 2002 didn't have the problem. You can either fix with epoxy or buy a new improved stator.

 

10-4 on bad flywheel

 

I'm guessing the only way to check that out is to pull the side cover off?

 

Yes. There are some videos on youtube, showing how to fix. I think a bad stator can kill the coil. I'd be inclined to buy the new improved stator, however, maybe a 2002 one may work. Check eBay, I don't think the fix is too expensive. Sucks, because it's a very nice quad, otherwise. I love my 2002, went out today, howling wind, just above 0F, and it started on the first click.

 

I wanted to fill you in on what I've learned. My multimeter is a fieldpiece. It has a Min/Max option for voltage checking and with Max selected it shows me the max volts being sent by the source & trigger coils. You mentioned not having a peak adapter & I've found nothing on the web that says anything about what I learned of my multimeter. Unfortunately my trigger has no signal for some reason. Hope this helps you in the future.

 

Sorry,in my dyslexic and weak mind, I meant to say, flywheel, instead of stator. I guess you downloaded a service manual? You didn't say whether or not that you inspected the flywheel magnets? I think bad magnets can still give a spark, but at the wrong time, not sure.

 

I tore into it and sure enough, some of the magnets are loose. I contacted the customer and he prefers new parts. So I'll replace the flywheel and the coil. There was power getting to the coil but no further and all my tests say it's bad so I'm replacing it as well.

 

Continuation of this nightmare: replaced flywheel, coil, and thoroughly cleaned the carb. Ran great. Took it to the customer and he was pleased. Called an hour later saying it runs like crap again. Long story short, I'll clean the carb and it runs great. Let it sit for an hour and it runs like garbage. It's done this repeatedly. I've cleaned the fuel tank, replaced the fuel line, and installed a fuel filter. Nothing seems to help.