Has anyone tried a JR50/FA50/OR50 piston in a Minarelli V1 yet? The V1 piston is about 39mm and the Suzuki piston is standard at 41mm. I put them both on the same wrist pin and they are almost identical except bore size. The crown height is the same, the skirt length is the same, and the transfer cut outs are too.
I know there is not much material in the cylinder wall by the transfer ports but it would seem that 1mm on each side could be removed. It might be a way to bring worn out cylinders back to life, and get a 51cc engine.