(you givin up on the lectrics? ) Grahm bell gives an excelent tutorial on the math formulas for small piston port engines. Lots of working examples. Nothing on crank ballanceing though. But every thing else is in there. Google will get you a bunch of places for a free download.
Has any one found a better rod for rebuilding these with? or better said a good big end bearing? I wll research for a yz60 or like that con rod. I have machine capability so resizing for a different crank pin is not a huge problem.
Just fishin for info.