RE: Spark ignition on YS170 DZ
When four cycle model engines first hit the scene-there were x spurts claiming they needed NO oil and some claiming 5% and some 10% on and on and on
going from OS-to Ys to Enya and Saito, we found that overall as competition engines that is run at max power a lot in paternplanes - a good all around oil content was 20% synthetic This was starting in early 1980s and after switching to gasoline and spark engines for larger models the same old discussions started again.
Less oil means more power
the answer to this is B U L L S H I P
aircooled engines require MORE lube than liquid cooled engines .and reducing oil to some measly amount just narrows the window on heat tolerance.