If you are talking about the tube going from the valve cover to the back of the air cleaner tube it is part number 67068. Should be able to order one through any good repair shop.
no i am talking about the emulsion tube which seems to also be the main jet it is the seat for the fuel adjustmenr the tube screws in and fits in a hole on theother side of the air barrel then the fuel adjustment screws into that it was bent and when i straightened it it broke but now i think i will solder it because i have a drill bit that fits and if solder gets in the tube i can drill it out