Hi:

I second the YS 110 in the UCD 60, mine is just great. Bottom line with the YS is its a great engine, period. People who have problems with them typically do not follow simple instructilons regarding the care and maintenance of the engine. Nothing unusual. Use the correct fuel and oil, in line filter and keep the valves adjusted, once after breakin and once a year. Have had around 10 of them through the years, never a problem. Best 4 banger out there, period. Best power by far, best throttle response, idle etc. Break in correctly, take the time to set idle and throttle correctly and fly foreaver. If someone bad mouths a YS, its because they are one of the clutz out there that will screw up any engine, even a 2 stroke. Never fails. (The guy that adjusts his needle after every flight, and never gets it quite right). You do not have to run the 20/20 fuel, I rely on 15% power Master for everythilng I run includilng Jett pylon engines. Must have the 20% oil. The OS is a just ok engine in my book, no longer have anything to do with them since their continueing screw ups on cylinder pealilng which still is not good. Any engine builder who sells on the high end and does not build them correctly does not deserve your backing. Many of the much less expensive engilnes such as Thunder Tiger and, Magnum, Super Tiger do it correctly and do not attempt to save 50 cents by reducilng the number of head bolts, or bearing quality. If you really want a outstanding 2 stroke engine, spend the money on a Sports Jett. Yea, costs twice as much and worth every penny. My Jett 35 is on its 4th club raceilng season, my 50 on its 3rd. Just keep getting better each year rather than falling off. Figure it out, they are my least expensive engines of all the 2 strokes based on performance and longevity. ENJOY