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How common is a cracked piston
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I have a 2020 YZ450 just shy of 80hrs. Original owner. Always changed the oil 1-3 hrs depending on riding conditions and ran a clean air filter every ride. How common is it for a piston to crack like this? 
I had a yz250f crack a piston with 40 hours on it. Not uncommon. But I wouldn’t say it’s regular.
I’ve seen it on a couple of 250 big bores, but not on a 450
Kawasaki was having trouble with it on the KX450 years ago, and ultimately went to the “boxed bridge” (or something like that) piston to cure it. Failure was like yours, straight across.
It looks like you have been having some detonation problems.
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My buddies 2021 YZ450 had the exact same thing around 60 hours.
2017.5 KTM 250 SX-F right at 99.8 hrs, almost identical failure.
This used to happen on my kx250f back in the day around every 50 hours. Sometimes it can be the type of fuel you run. Not that uncommon id say. Original motor?
It was a 2007 kx250f for reference. I’ve yet to have this happen on a newer bike.
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