I'm Korean. I'm here for your help. The piston ring broke a while ago. So I replaced it with a new one, but there's no problem before the heat comes up. When the heat rises, the engine vibrates more and the muffler sounds louder, so there is no output. It's frustrating that the person who repaired it doesn't know the cause. Everyone, help me. I don't know if the delivery went well because it's a translator.