No, I got parts, and more parts. I cleaned up the cyl and it looked useable and installed another new Meteor piston. I did check the ring end gap and filed them for the .008 gap. Less than 1/2 tank of fuel and the very same failure occurred again. Ruined piston and another chunk missing from the exhaust port. This time I threw out both the cyl and the piston and replaced them with a new OEM kit I recently acquired. Press/vac tested on reassembly successfully and away we go. I’m now into the 4th tank and the saw has settled down into normal behavior.
I’m not sure exactly why I was having that problem. When I bought the refurbished OEM cylinder I was surprised to find the exhaust port beveled quite a bit. In the cyl’s I’ve cleaned up, all that was necessary was Scotchbrite and Purple Morado (caustic soap) used to attack the aluminum transfer. I’ve never had to grind on anything. I can’t say for sure why the pistons failed, but after two, I’m not risking a third.
The failures mimic that which occurs when overspeeding the engine according to a very informative Madsen site diagnosing piston damage. But I’m certain that wasn’t the case here. Don’t know what happened, but OEM stuff appears to have fixed it , so far. Although this saw was built for a friend, I’ll be keeping this one for a while and using it, rather than risk a failure with him. Appreciate all the interest and suggestions.