Dec 11, 2007· Here's what I have done to my sons pw50, Then head is milled 25 thouhs, had the ports cleaned up, bored over to 41mm, boyesen power reeds, fmf pipe, fmf powercore 2 silencer, moose air filter with 2 one inch wholes in the stock air box, and I'm using the stock jetting, 70 main and it is running awesome, check your spark plug and look at the color of the porclein tip, it should be light ...