a chopped piston with a titanium ring should come pretty close to the right weight. I cut an intake window into my piston and drilled two 1/4" holes next to the wrist pin to reduce weight and got it down to about 97g from 106g if I remember right. With a titanium wrist pin, that should drop right down to 89g, but I havent got that far yet, even now with the heavy pin I'm seeing far less vibrations than stock. You're right, they are balanced for the 50cc engines and thats what I was aiming for with this thread, but as far as I can see, noone has the actual weight. I imagine if I can match it, it'll run damn smooth.
Though if I get the hoca piston, iron rings, titanium pin and a silver race bearing, I should see the same 97g assembly weight, and crank more power and efficiency. I still have a long way to go with this motor, particularly because a lot of it was just pissin around learning how it works, just waiting on the money for the replacement parts and the *proper* aftermarket parts, to get this thing hauling. Though I have been thinking about case induction since I saw arrow's race motor had it, and now that someone's actually doing it with a nearly step-by-step guide, I may go that route later on. I still have some more measurements to do so I know my limits, because I want to improve transfer efficiency as well, the transfers in these engines are garbage, and most even let fresh mix straight out the exhaust (terrible shaping).