Was it air leak/Crank seal/Ethanol Detonation?

[slowfusion]

What do you guys think fragged this piston, leaving the cylinder clean?
2002 800 Edge, HTG twin pipes, shaved head,SLP air kit, OEM pistons,Cylinders all done 4 seasons ago.

 

[o2bncamo]

Looks like something went through the engine. The head rarely shows damage when there is detonation. The damage is also heavier on the exhaust side. Maybe a piston cage bearing let go?

 

[slowfusion]

Got the jug off and while pulling VES noticed valve was loose on that side and after jug was off found bottom ring was missing a 1/8" piece, tore a grove in the center side of piston but no damage to cylinder wall,(LUCKY!!) My best guess is mixture of cracked ring and air leak. Looking like a gasket, seals, hone, new pistons, head. Gonna put a dial on it and check for phase also before I finish tear down.Hope the lower end is good.
In the pics you can see were the piece caused all the damage to side of piston but wondering why it would have broke in the first place?

 

[slowfusion]

OK, more damage the deeper we go,,

Opened up case and outside bearing came apart,