I finished the S1C today and fired it up. It ran great for about 5 minutes and when I shut it off as the engine was spinning down I heard what sounded like a circlip going through a cylinder. It sounded like the left cylinder so I pulled the head and there was a few impact marks on the top of the piston. I tried to pull the jug but it would hang up on the rings. I pulled one circlip(they were both in place)and the piston pin and then I saw the bottom ring was shattered in about 10 pieces. I don't know how but the cylinder is unscarred and the piston has a few burrs near the top so it should be okay. I ordered a new ring set but I considered checking the old rings to see if one was in spec so I wouldn't have to wait but I don't like the thought of having a used piece in one of my builds. I'm going to make sure the ports are chamfered acceptably before it goes back together. The cylinders were in spec so they got honed and new pistons and rings installed when the engine was assembled so the old rings would probably work. By the way it was $70 for a single ring set.
Also, did the ring pieces all go out the exhaust or are they in the bottom end?
You'll probably find most of it in the exhaust pipe. Check the exhaust port at the top. That's usually where they like to grab the piston. Check the piston and make sure the arrow is pointing to the exhaust.
