Moped Army

Those piston ports, I just use a dremel tool with an 1/8th inch carbide burr. The burr is the smallest I could find and I think its used to remove grout between ceramic tiles. I don't drill thew the piston and I'm carefull not to hit the lower ring land surface because that holds combustion pressure during the power stroke, Only the upper ring land surface is ported.
I'll be prepping more pistons soon and I'll take better pictures and hopefully I'll know how to post them.

Keeping the focus:
this mod takes advantage of stuffed crank motors and consumes some of the unwanted overpressurization in a way that improves horsepower and reliability beyond what has ever been achived.