Rod carnage....... Lol

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With that bend the piston must have went out the port or the cylinder failed spectacularly!
 
With that bend the piston must have went out the port or the cylinder failed spectacularly!
Agreed. Do you have a picture of the jug? If it were a matter of something blocking the piston, there would be a 2nd bend somewhere in the rod. The fact that it's bent in 1 spot tells me that the rest of the energy was absorbed by something other than the rod.
 
Stihl FS90.
One of the original wrist pin clips was in the bottom crankcase pan.
I'm assuming the wrist pin shifting to one side caused stress on the piston enough to rip a web out of it, then on the return stroke it slammed the piston hard enough to bend the stamped steel rod.
The cylinder and valves weren't damaged.
 
My guess.....too many RPM's jerked the wrist pin out of the bottom of the piston by breaking out the pin holes....and then the rod commenced to hammering the bottom of the piston and got bent as the crankshaft coasted to a halt!
 
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