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So just rebuild the top end on my yz 250 and finally got it to run. And when it did it ran wide open which I later figured out to be the throttle cable was messed up. Anyway before it started and I killed it, it was easy to kick and everything but after it ran it's so hard to kick now its like in a bind and then when you finally get it to go down and it comes back up it's hard to kick again. I looked in the spark plug hole and seen what looked like to be some metal shavings on top of the piston. I'm expecting the worst out of this cause I figure that's just my luck so let me know what you all think the problem is... thanks

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What I might think would just be a guess.  At the very least your pipe is coming off so that you can look in and see if the piston seized and what shape it is in.  you may have an air leak that caused the runaway too, unless you found the throttle was definitely stuck.    

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The throttle slider thing in the carb was over halfway up with the throttle not being turned. I don't know what is going on with it. I think I might just sell the thing as is...

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What I might think would just be a guess.  At the very least your pipe is coming off so that you can look in and see if the piston seized and what shape it is in.  you may have an air leak that caused the runaway too, unless you found the throttle was definitely stuck.    




So just rebuild the top end on my yz 250 and finally got it to run. And when it did it ran wide open which I later figured out to be the throttle cable was messed up. Anyway before it started and I killed it, it was easy to kick and everything but after it ran it's so hard to kick now its like in a bind and then when you finally get it to go down and it comes back up it's hard to kick again. I looked in the spark plug hole and seen what looked like to be some metal shavings on top of the piston. I'm expecting the worst out of this cause I figure that's just my luck so let me know what you all think the problem is... thanks

Yeah my boot had a tiny crack in it once that caused a huge rise in RPMS

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I did and there is metal on top of the piston but the cylinder walls seem to be fine so wth happened 

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Yeah...if the cylinder is not messed up then where did the metal come from? The rings?

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Yeah...if the cylinder is not messed up then where did the metal come from? The rings?

Not goooooood at allllll

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How hard will it be to replace all that? How is that even possible.

30 minutes. Just get another top end kit but I'd say the cylinder may need a touch up. It's probably got some scoring

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Man I don't want to do this again. So I will more than likely get a shop do it. Only thing is the labor price I'm still not sure of

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Man I don't want to do this again. So I will more than likely get a shop do it. Only thing is the labor price I'm still not sure of

Do it yourself, it's way easy to do and this sometimes happens, it say you didn't pinch the ring properly and it wasn't seated 100% right. Do it again because you'll be gratified by your own work it's awesome
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I don't think so man, that was my first time rebuilding it and that's the results so I don't think I can and if I mess it up again I'm just out of the money

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2002 I have a online manual. I don't have the paper one since I didn't buy it new 

Look at the Pitts in the top of the piston too, that's the other issue

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Sometimes a piece of a broken ring can pit the top of the piston like a pinball in a pinball machine. You should see problems on inspection. Keep your chin up, this is how you learn . Probably nothing you did, don't take it personally.

 

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