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Discussion Starter #1
Hi i hope im posting this in the right section i have a 98 grizzly 600 it was running great i was out on the trails a few weeks back and she sputtered backfired and stalled even blew a hole in the intake boot. My buddy i was riding with towed it home and i found it lost spark. I narrowed it down to the stator and replace it with a ricky's stator and it now has spark and runs but very poorly. it idles great but when i go to give it throttle it sounds as if the air filter is plugged and it lacks power it wont go full throttle. i have checked the following and it was all ok: valves, compression, carb, new intake boots, all electrical seems ok and working, exhaust is not plugged. Anyone have any ides? i will try and upload a video, thanks.
 

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Welcome 2 GC, have you changed the spark plug?
 

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First replace the spark plug as already recommended.

If that doesn't cure your problem, check the flywheel woodruff key. Unfortunately you'll need to pull the stator cover off again because you'll have to pull the flywheel off in order to inspect the woodruff key. This is the only sure way of inspecting that key.
In many cases when you have a sudden backfire or misfire, the violent reaction can shear the key. Have replaced a few on older Yamaha's....one being my own.

I also highly susgest you check valve clearances. Tight valve will give you running issues. Sometimes they can cause back/after firing and hard starting (especially when cold).
 

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Discussion Starter #5
I have checked and adjusted the valves to spec, I will pull the flywheel and have a look at the key thanks for the reply! Would it still run with the key sheared?
 

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I have checked and adjusted the valves to spec, I will pull the flywheel and have a look at the key thanks for the reply! Would it still run with the key sheared?
In most cases, no it will not run. That's why you should change the spark plug first. Do the basics first before moving on to more intricate.
But I have seen one Kodiak 400 that was running with a sheared key. It was backfiring and generally running like crap, but it did run. It took me quite a while before I figured out the key was sheared because of this.
 
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Discussion Starter #7
put in the new plug still ran like crap, checked the flywheel key it was ok i am not able to post a link to the video :/
 

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I assumed you have already removed and cleaned the carburetor. If not, this needs to be done. Remove and blow out all the jets. If you find small black rubber pieces in the carb, then replace the black fuel hose from the fuel petcock valve to the carb carburetor as that is where the rubber is coming from.
 

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This is a real head scratcher. The only thing I can think of now is the stator assembly you installed is bad. Possibly a bad Pulse coil. Check Pulse coil resistance. Should be somewhere between 420-600 ohms (approximately). Over 600 ohms is bad. Under 400 is also bad.
If I remember correctly, it's the brown and green wires on the white square connector coming from stator....NOT the round connector.
 

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Discussion Starter #12
Tested ok, also forgot to mention that this is the second replacement stator I bought a cheap eBay one first and that one was doing the same thing
 

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Thanks for coming back and actually closing this thread properly with the fix. I really appreciate that, and I know many others on this forum do as well.

Now go ride!
 

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^^
X-2, thanks for the update.
 
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