stalls out after its warmed up

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We1Dont7Die

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I swapped out my cdi with a used oem cdi today because i was told that might be the problem and i still get the same result. Runs for 10 minutes then starts to sputter and die. starts right back up but again, sputters and dies unless you keep the throttle on. I have tested every electrical component and i believe it is all good.
I went to use my compression tester today only to find it does not fit in the spark plug hole..still trying to find one that does. am i on the right track? :argh:
 
sounds like a fuel flow issue , bowl running out of fuel? have you checked or cleaned the carb? possible cloged vent hose off gas tank ? try unscrewing the cap a little when it starts to sputter.
 
I rebuilt the carb and the pilot screw is 2 turns out. accel. plunger moves freely and float has no cracks in it. float needle also looks good. hoses are all clean as new. yes i tried unscrewing the cap and it did not help. The funny thing is that when i go riding i can be out all day with this thing and even though it will die at dile, it will still reliably start up and get me back to the trucks if i keep giving it throttle.

I have been trying to fix this for weeks now and I'm starting to think I should let the professionals handle it even though the thought of that makes me cringe and goes against my very being.
 
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it could be a compression issue, once it warms up the metal expands and loses compression? you would think it would burn some oil and smoke? hows your spark plug
? ........someone else needs to chime in here
 
So you can ride for a few hours before this starts happening?
 
i might be reading this rong but
if your saying it conks of once its warm , it is probly the idle ajustment as the engine gets warmer it needs more fuel to keep it running!
 
I'm going to make a video of it tomorrow if possible.

So you can ride for a few hours before this starts happening?
No, I can ride WHILE it's happening. if we all come to a stop around a bend or something on the trail i have to keep giving it gas or it wants to stall. i can ride it all day like this though.

Spark plug doesnt look fouled. its a dark gray
 
you have to be losing compression somewhere when it gets warm like a headgasket ,rubber intake ,it could be a really small crack in the headgasket that expands once its warm ,if your sure its not the carb,you really need a compression test on the cold engine and when the engine is hot,any local parts store should have a adapter to fit your tester
 
So I picked up a new compression gauge that came with 3 adapters and one fit the quad. I will be doing the compression tests tomorrow, once while cold and then while hot. I'm new at this so do you guys have any tips or advice for me while doing this procedure?
 
screw it in and hit the start button, check it. Then do it again when the motor has warmed up. You should be at at 115.
 
OK guys. I did the compression tests and i got 150 while cold and even after it warms up i still get 150. its higher than what the manual says it should be. could the engine be overheating because of carbon deposts or is this level of compression ok?
 
I adjusted the valve clearances and I am STILL having this nightmare problem. I'm all out of ideas.
 
went riding (yes i can ride if i just dont let the bike shut off) and met a mechanic on the trail. he thinks its def a fuel problem. I swear to god i cleaned that carb out so many times and the parts seem ok. I dont know if its a fuel problem, im starting to suspect that although my stator is checking out ohm wise, it might be screwing up when it gets warm.. I need to ride, help me guys!
 
Yupp check ur stator. When mine went out, I could ride it but it wouldn't idle (not a strong and steady spark) Anyone on the fist YFM ride will remember that night, I had to keep the revs up just to get back to camp. Next moring I had nothing. Popped in a new stator and its been fine ever since.
 
Thanks for the response DeadLast, I really need all the input i can get.
It's gonna be expensive to get a new stator so I really want to be sure that its the problem. Is an inline spark tester the only thing that will help me diagnose the stator? The OHM readings on the multimeter
are fine which is the strange thing.
 
Humm, you ohms test fine? Weird. You tested the stator and coil?

U pull the plug and look at the spark? Its it bright blue and constant?
 
Yes i tested every electrical component that could be tested. I havent pulled the plug after it gets hot and acts up. I guess the next step would be to let it run til it acts up and pull the plug out and check spark? I just dont like cranking my starter over and over, i just replaced it and have been using it a LOT because of this problem. infact the battery is dead because i went riding two days ago and had to turn the engine over so many times to get it to start every time.
 
fuel line is good and i just put a new fuel filter on a couple days ago which flows better but the problem persists.

my stator is reading 300ohms from one set of wires and 496 ohms from the other set. this contradicts what the manual says but other people say its fine...?
 
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