Hi
CZ fork tubes are 35 mm from top to bottom if they are original or new , when you are having them re chromed remember that they have a taper at the top, where they tighten into the top clamp,
when re assembling slip an 8mm spring washer into the lower fork slider ,where the damper rod goes ,this make it easier to undo the damper rod bolt when you disassemble next time,if you are replacing the circlips that hold the oil seals in make sure the ends dont scrape your new tubes , two 35 47 10, or three 35 47 7 seals, try NAK seals,you can get them from that little bearing shop next to the Kawasaki shop in Albion,
cheers