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I am struggling to find 99mm head gasket for YFZ450 carb model

Toph

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Joined
Jul 15, 2025
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3
So blew a head gasket and wasn't sure of the big bore size, so I measured the piston and cylinder, and it came out to 99mm, I have been hoping to find a 99mm head gasket for a YFZ450 carb model, but no luck. Did I measure wrong, or is this size uncommon?
 
Many years ago I helped a buddy of mine replace the head gasket on his 06 450, the carb model and I remember that we were looking for a 95 mm head gasket. Could the engine be bored out? Might want to remeasure, but if that's the case you may need to start thinking about a custom gasket.
 
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