[link=http://www.novarossi.it/eng/products/engines/rex/plane/features.php?name=R50F&display=public]Rossi[/link] (Novarossi Rex) are now doing something similar with their crankshafts for plane engines but it's a common feature in car engines. The car guys are mad keen on doing things to their engines in the hopes of gaining more power and they'll cut away indiscriminately at the crankshafts grinding channels in the crank web and knife edging the leading edge of the counterweight (similar to that Rossi crank) but giving no thought to balance issues. I must admit I've always had my doubts that there's anything to gain from it because even at very high revs (30K or so) the diameter involved is very small. However if Rossi and Cyclon are doing it then there must be something to it.