kip they put those stickers on because they ran out of the orig ones lol the easiest way to really tell is the 50 box says ie40f and the 80 is ie47f how u like that thing? they are really slow till broken inOk, here is what I know now about my slant head Pizhou Yongxing "50" cc motor from Zoom. Despite the fact that the sticker states 68.5cc it is indeed a 48cc motor as ordered. the bore is 1.575" or 40mm. The stroke is 1.483" or 37.668mm. After doing the math for cubic centimeters I arrived at a value of 47.728cc. The piston is flat and originally came flush to the top of the jug but now rises above it by .023" because I replaced both gaskets with hand cut aluminum gaskets. The studs measured 6mm. Hopefully this data might be of use to others.