ran real well this year with the old yb quad now my buddies. threw on the o'connor YB killa cylinder and this happened on the last practice of the last race of the year. the one thing i cant explain is the carbon on top of the piston. but here is the damage.
intake side
exhaust side
wierd carbon build. the clearing is on the intake side.
intake side
exhaust side
wierd carbon build. the clearing is on the intake side.