Picked up an Evolution .40 still with the flywheel ring. It surprised me a bit with a run of 16,900 with no muffler, and 15,000 with the stock pretty muffler. I took it apart and noticed that the crank is blended on the bore. I think that is a good detail for a cheap motor to have. I radiused the top sharp corner with the little grinder. I can not remember if that was done before or after the test. I ran another Supertiger that I got that day that said G.40, and it did 15,000 with the muffler. It was an odd muffler, not the new one or the one that pivots.