RE: ys engines
Even the two stroke YS's all with the same pump system Were superb engines. The YS pump system is a hugh advantage for sport flyer or competior of any discipline. Fuel tanks can be put anywhere you want them high or low, close or far away, multi engine tanks in the fuselage. The ability to put the fuel on every airplane (any airplane) on the CG alone is worth the price of admission.
John