i bought a vernier calliper its not very precise but is ok for up to .5mm accuracy ,, tomorrow i will pry engine again to check the bore stroke,confirm the installation of rings was done correctly previously,clean the oil filter screen,and also will adjust its valve clearance,, also will try to install a new bigger carb,,, and the carb installation will b a really painful job,, cause on one hand jets r not up-to specs , and have different threads and availability is very scare,,its a 22mm carb,, couldnt find pz22 carb installed in hero,, but found one in the same shape as of 70 but bigger venturi,,22mm,,,all of its jets ,tube,needle etc r unlabelled,,infect the only label on it is a funny adulteration of keihin name,,,,