Just came across something pretty cool on ciao nl. It looks like there exists/existed another small case half kit with induction through a hole in the crank, they call it the "TURBO / “ATG side inlet". This specific setup appears to have come with a special crank that not only utilizes a larger bearing for a much larger hole in the crank shaft on the small side . . . but implements these series of "slits" in the side of the crank to, as they put it, "mix the gasoline with the air well and thus get better combustion".
This is super interesting, photos attached. I guess these slits maybe help to grab and "swing", in a way, fuel around the crankcase to better homogenize the air/fuel mixture?
I wonder how much more effective this is, and if it's only significantly more effective when you have such a larger side intake pumping more fuel. This one looks like it's maybe even 19mm, it's huge. Would a rotary intake only setup benefit from something like this? Pretty cool, I have never seen these before that's for sure. It's pretty badass how this half uses such a larger bearing and cup in the small half to allow for such a bigger hole in the shaft. I guess it's only possible when you are requiring a specific unique crank.