Lady flyer I disagree with you that anyone that disagrees with you about the YS engines is a below average sport flier or never run one. You are totaly out of line in both points. Your opinion on the YS engines is just that your opinion, and we all have one. I for one have been flying RC since 1970 and have flown quite a few 2 strokes and 4 strokes over the years and that includes the YS engine. The YS engine is a good engine for what it was built for. Power and performance, and with that comes some some benefits and some problems. I for one fly for fun and performance and the absolute demand for power is not a factor with me. With that pressurized fuel system which works great can be also a major cause of problems over time. You develop a air leak in that system and you can have real headache trying to find it. I have seen fellow flyers ready to pull their hair out trying to figure out why their YS engine won't run. I for one will say this for the average sport flyer that does not need or demand the absolute in power and performance go with something other than YS. This is from experience with the YS engines and others that I have flown and is my opinion which we all have.