Bills: Great news on that tile-cutting burr, that is what I need. Where did you get it? What do you think. Maybe just making the exhaust port wider and leave the timing alone would be best. What happens if you cut the botttom of exhaust port to get more flow? On that throttle....the shaft broke and now the control knob and shaft has to be held in. If you take it out the air mixture goes way off. I am going to take that one back for full refund. The last dealer I took it too cannot get parts. MTD will pay him 1/2 hour for paper work. Bottom line.....NO PARTS for the MB290 0r YM290= Yard Man.