200hrs on a 250 is pushing it. I pulled a top ring out at .9mm at 110hrs on mine.
As for the cylinder, such is the price you pay. By leaving the piston and rings go so long it allows the piston to rock in the cylinder a bit. I'm betting the piston has some decent wear on the skirts.
In saying that, it also appears the clylinder hasn't been cleaned at all yet, so before you draw too many conclusions get a scotchbrite pad and some carb cleaner and give the cylinder a good deglazing. I'd then suggest measuring the ring end at several depths in the bore, or having a shop spec it up with a bore gauge.
|