i just got a 95 kx125 with a fully rebuilt engine and the previous owner said he richnend up the mixture for break in I was riding and I got into 3rd gear and the bike just shut off so I pushed it back and I noticed like gassy oil puddle underneath where the pipe and silencer meet. So I took them off and noticed a that the gassy oil would run out of the pipe. So is that because he ran it rich? Should I let it air out overnight? I tried to start it and it would only run off of carb cleaner after that burnt off it would shut off