a fuel dot is used with a 3 line tank system....1 line from the muffler to the tank for pressure, 1 line from the clunk in the tank to the carb, and a 3rd line from a second clunk in the tank to a fuel dot. A fuel dot is just a collar around a hole in a cowl. The 3rd line is used for re/de fueling..and has a stopper in it when not in use to keep from venting pressure in the tank, and to hold the line in the fuel dot,
there are other ways to set up refuelers..but a fuel dot is not a refueler...its just a collar around a hole..
Hope I answered your question with out confusing you