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Has anyone seen this problem before?

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When I was at the track last weekend, my 09 KX450 died and I couldn't restart. After pulling it apart I noticed that the mark on my flywheel was not aligned with the notches on the engine cover at TDC like it should have been. So, I removed the side cover to take a look and was very surprised. The notch on the crankshaft that keeps the flywheel in the right place had broken off!!!! :banana: I wouldn't even think that it was under much stress, it just spins. This bike is only a year old!!! The nut that holds the flywheel was tight, so I can't think of anything I may have done to cause this. I am going to have to split the cases and get a new crank. Has this happened to any one before?

Wayne

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Did the flywheel break off ? The crank end break ? This new to me/ need more

info or you need to talk to your dealer.

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Sounds freakish. Even if you shift without clutching, if installed correctly, it should not happen. If the nut was loose, then I'd guess that anything causing sudden crank rpm changes would load that key piece a lot!

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The flywheel seems to be okay, the only thing messed up is the crank end. It just has a little notch that goes inside the flywheel and that is what broke. Now the end of the crankshaft is smooth so the flywheel won't stay in place, it actually spun on the shaft. Like I said, I've never seen or heard of this either and I will probably talk to the dealer today.

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Do these not use a woodruff key? Surely its just a simple cheap part broke and looks as though its flush with the shaft?

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yeah sounds like the key broke. did you ever jump a gap short, or bottom out so hard that your engine died? anything that caused your engine to die at high rpm?

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Oh man, you guys are right. I am so releived, thank you for your help. I hit a big mud hole and the track and that caused it to stall, almost threw me off the bike too. The reason I thought I needed a new crank is I was looking at the microfiche and I didn't see a separate part for that. I guess I just didn't look hard enough!!

Wayne

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If there is no sign of damage on the crank or metal in your oil, its possible the woodruff key may have never been installed.

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