the CP top fuel piston weighed 862 grams, I gotta get rid of a lot of weight from it. This milling removed 60 grams. At least 150 grams left to remove.
I made these buttons for the gudgeon pin ( instead of circlips) -guaranteed to never fall out. note use of an aluminium rod to hold the piston on the milling bed,

So now its finished, and weighs 679 grams. now time to start balancing the flywheels
