[quote]ORIGINAL: Gray Beard
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Another question I just have to ask is what is different between tuning a YS and any other four stroke? I keep seeing people that have never owned a YS state this over and over. I really would like to know what you think is so hard about a YS and maybe I can inform you about the problem. The older YS engines were/are a balancing act between the high end and regulator that some people were never able to figure out. An inquiring mind really wants to know.
In my experience the fuel regulator is what gets most new YS owners in trouble. Since many of them are "supercharged" that fuel reg can be confusing. That being said, the newer ones seem to be set up pretty good from the factory and as long as you don't get overly fiddly with them, aren't much of a problem. I do know my .63 does NOT like to get too hot. Had it in a P-51 and it literally dropped the valve guides into the engine...twice. It will never be in a tighly cowled airframe again. But boy did it ever work awesome when it did!
My fuel of choice on all my 4 bangers is Powermaster YS/Saito 20/20. Sure glad I hoarded me a supply before they went away for a while...