I'll bet your ski got hungry and ate a screw. Post pics of the carnage.
U should do a complete rebuild, especially on the bottom end. You're pretty much guaranteed to find metal shavings down there, and you don't want to leave them there.
Yep,
Without a doubt, if you broke a piston skirt there are metal shavings all inside of the motor, in the bearings, seals and everywhere else. IN my opinion, if it were my motor, I would go through the whole thing, TRY AND DIAGNOSE WHAT HAPPENED, so that I did not blow up another motor when I got it back together.
You put a top end on your ski without cleaning up the bottom end and it will happen again.
BTW, I don't know where you got your 12K number, or how much you want to spend, but you could do a pro-built arm strecher for 4-5K or a real serious motor for 7-9K.
Brian