how replace burn valve

there is a limit to DIY I guess. thanks . Will replacing a burned valve take a long time. I would like to think its as simple as removing the cover, remove worn vavle and drop in new valve. When a valve is replaced is there something else a mechanic should do as good practice before putting everything back together? thanks in advance.

There is a limit, and those limits are increasing every year. This requires partially disassembling the engine to replace a valve. I answered your other question and asked a few questions, did you read my answer?