typo I suppose ?
SK I agree on power gain, but Putting a bigger bore piston is not being very good in alteration if it is not done by a professional way, now by professional way what I mean is that ZPF engines come with cromium enameled pistons/Cylender and they donot go bad for 50k(km) if used like a comuter (as it is actually a comuter)
when we bore out a bigger piston then what happens is that Piston is named no enameled (worse can be if its local) also the enamel layer is now gone and this time the piston and Cylender are gong to grind way fastly then orignal and would may work below 10k(km) before going bad and start to smoke secondly this time you would definatly notice more heating becuase metal grind is more and oil and air cooling will be noticed failing to support in summer specially...
I keenly noticed this problem in few CG and a couple of RPs then I discussed it with the chinese friend who helped in bring in the engines, I want to see who much time in actual will the feaveo's bike will last.. lets hope for the best.