It is true! when checking pistons and cylinders of an engine we do not know how we will find them. Good thing you found a new set.
At home I have seen pistons with super glued rings, but they are left in a bucket with diesel oil for several days until they loosen and are easy to remove, this is if you do not have ultrasound.
I congratulate you for finishing the job. I look forward to seeing the next job. Greetings and success 👋👋👋👋👋.
RE: Z650 Engine Rebuild Winter Project - #14: Piston Problems