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Yz450f issues starting

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I recently picked up a 2004 yz450f that has some issues starting but runs fine if bump started. I have put in a new spark plug, cdi box, cleaned the carb, cleaned the air filter, shimmed the valves correctly, and corrected the timing but still can't figure out what's going on. I tested the spark with a new cdi box and plug and got good spark but every 3 to 5 kicks I'd get no spark for 2 to 3 kicks which concerns me. And it starts up after I test the spark, almost like it starts after it's cleared of fuel but otherwise will not start unless bump started and once it does run it runs great from idle up but dies when it's warm. I'm thinking it could be the stator, does anybody have an opinion on this?

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You have the classic symptom of a leaking intake valve or a dying stator. 

The leaking intake valve means the head is just worn out, and the valves are no longer sealing, until they get hot.

The stator is typically more about bad harness connections or it being overheated too many times.

More symptoms would help narrow it down.

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