If you fiddle with YS engines as if they are like 2 stroke, you will have a problem. You only need to know a few basic things about YS to derive maximum benefit; yes YS are different; they have to be to produce so much power and torque for minimum weight. I fly YS (most of the time) all sizes without any problem. There is enough information on the YS manufacturers support forum for anyone to tune YS engines. Inspite if someone does not follow, there are several (including myself) who will advise om how to resolve any issues.