Well i told you it works good on youtube one time. U asked about it in a vid and i told u how to do it. XD Fixed my lil chinese 49cc head, it wasnt flat and oil was spitting out the side. Just got a sheet of glass, very fine grit sand paper, wd-40 on the wet n dry and moved the head in a circular motion on the sand paper. I had to sand mine for about 5 minutes till it was good enough. When i put the head back on i still could see a gap between the head and the barrel n found the barrel top wasnt flat either. **** CHINESE QUALITY!!! I didnt bother sanding down the barrel but oil doesnt spit out of the side now so idk haha.