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runs...backfires...quits!

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Hi, my STOCK 04 YZ250F decided to act up this weekend! It warmed-up fine, rode for about 10 minutes fine, then started backfiring like crazy, then it quit...and I couldn't get it started! I let it sit for 20 minutes, changed the plug, and the same exact thing happened! Gas is good, filter is clean, plug is new...HELP!?!?!?!?!?!?!

Thanks,

Bill

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Mine will do that if I forget to turn the gas on. I know you have it on but is it possible there is a clog in the tank or line and the gas only seeps through slowly? That would explain it starting up again after 10 minutes. Next time it stalls pull off the gas line at the carb and see if it is flowing freely. Probably not this but hey you have to rule out the obvious first.

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You're getting air into the carb somehow. Maybe a torn carb boot or maybe a clamp came loose on either side of the carb. I went through exactly the same thing. Look around down there. Good luck. :thumbsup:

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Thanks for the advice...I pulled the gas line at the carb, fuel is flowing with no problem. I drained all the gas, put new gas in...same problem... :thumbsup:

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The boot from the airbox to carb is tight and I don't see any tears. The boot from the carb to the cylinder is loose, I don't see any tears...I'll tighten it up and keep my fingers crossed! Thanks for the tip!

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It might be worthwhile to check the hot start also as air can get in through there. I had a problem once with it cutting out because my hot start was loose.

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sounds electrical to me.

make it do it again, and then pull the coil off of the plug and put a new test plug in the coil. lay it down on the rear bolt head with the gap facing up.

kick it over and look for spark. since you still have the plug in the head use a bit of duct tape to keep the test plug stuck to the head.

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the boot is now tight, unfortunately I have the same problem! I checked for spark and I only get spark on one of ten kicks! HELP!?!?!?!?!?!?

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the boot is now tight, unfortunately I have the same problem! I checked for spark and I only get spark on one of ten kicks! HELP!?!?!?!?!?!?

get the book out and test the stator. If the stator is bad one of the resistance measurements will be wacked. Sounds like the stator is kaput.

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YZ250F_Rider was right...it appears to be an electrical problem...I'm creating a new post for help!

Thanks for everyone's input!

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