I have a 98 300 xpress that has given me a bunch of problems in the year that I have owned it and recently I rebuilt the top end with a .75 over piston. And ever since I got it running again it smokes worse than before I rebuilt it. I did the rebuild because the compression was about 78psi hot and it had trouble starting. Now after the rebuild it has 131psi hot. I am on the 3rd tank of gas now and the first 1 was mixed 40-1 just like the manual states. I was not all that worried about the smoking with the first tank because it was running with the oil injection and mixed gas per the helms manual. But now after 1 tank of unmixed and just filled up the 3rd it is still smoking. I suspected the oil pump was over pumping so I disconected the cable and drained the oil tank. And filled the gas tank up with gas and smokeless 2stroke oil at a 40:1 ratio and after about half of a tank has been used it is still smoking. What could the cause of this be. Does it take a while for extra oil to be burned out of the case and such or what.