gas tank venting and the fitting "size"?

hello out there in GRiSO land.
i have pulled off the gas tank to paint it and found that previous owner must have had the tank off at some point in it's prior life. i was surprised to find that there were no vent lines and no vent fitting on the under belly just the female screw socket where they should have been screwed into? apparently the overfill and gas tank venting were just being open to the world right there on top of the engine? good thing never over filled gas tank. operationally it must make no difference if there are vent lines or not?
with all the said i wish to add vent line(s) and route to some place more appropriate, as you can imagine there are no spare parts currently available and 6 to 8 weeks wait time.

does anyone know of the size fitting that threads into the brass female that is imbedded in under-side on gas tank?
i was thinking of tiring to find a brass fitting with a nipple on the other end and just attaching some gas line gas for the routing.

thanks in advance for the help..

Does your bike still have the charcoal canister fitted? If so the tank vent should be connected to it. If it isn't I'd expect it to run a bit oddly at idle.

Not sure of the thread size on the nipples? I'd guess 8x1.25 but I can't be sure. Why not just buy a couple? It's not like they are big money. About $12 AU each which at current exchange rates should bake them about $8 US. Part # is GU30103730

no cannister, yes it does idle oddly, but not troubling. will source the vent fittings, just thought someone may know size just for reference.
thank you..

I found that the screw brass fittings can be bought from a radio control model shop, think they were for fuel tanks - trouble is can't remember size

as a follow up - found that they are 7mm - used bleeder screws and cut off the small pin hole end of threaded section - works great - $6.48 for the set..

Try and make the water drain hole [bleed screw] as big as you can as it blocks too easily, the petrol side isn't an issue.