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2 Stroke 200 Hp cylinder damage

HumberJewel

Contributing Member
1987 Yamaha 200 Hp 2 stroke.
Piston broke at the wrist pin then got pounded by the connecting rod.
Note the rust in the top part of the cylinder.
If you zoom in on the cylinder you can see that two of the transfer port passages are completely opened up, Both the steel sleave and the cast material that was behind it is gone.
It was running fine at about 5000 rpm when there was a noticeable loss of power. It still made it to the dock. Disassembly was 2 weeks after the failure. Fresh water.
What would cause such a failure?
Is the cylinder salvageable?
 

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