Regarding cantilever cranks, yes, I was referring to gas engines only and 20 cc or above. Glo engines are usually smaller engines compared with gas engines and usually have less reciprocating weight with aluminum rods, no heavy steel needle bearings and light weight pistons. Most gas engines have a lot more thrashing around inside with much heavier steel rods, needle bearings and much more robust pistons. Even if the cranks don't break on some of these engines, at high RPM, flexing can exist that can rob the engine of power. Add to that, many cantilever crank engines are light on counter weight and this shows up as increased vibration at high RPM. On gas engines, a crank supported on each side of the rod makes for a longer service life with less vibration. With few exceptions, most industrial or other heavy use 2 stroke engines don't use cantilever cranks.