its an oil connector. it shows in the description of the carb u gave in another post. it probably works without it connected. jsut make sure u seal it off. else dirt and such can get in.
heres a link to the one most people use
http://www.euroscooters.nl/shop/product ... cts_id=155
i reckon your tomos aint working properly as u didnt adjust the sproeiers(dont know the english word for it.)
http://www.euroscooters.nl/shop/product ... ts_id=1764
those are sproeiers. they change your fuel/air ratio. if u dont have the proper ratio yout moped wont start, or atleast run bad.
i reckon with such a setup u need del'orto sproeiers and most likely it will be between size 65-70. depending on your exhaust. i really suggest u try to find a moped shop where they can do this for u if u dont have anyone to help you out. its hard to get the proper one.
grtz,
xander
EDIT: basic rule for adjusting yer sproeiers. after driving a few minutes on topspeed and u stop then the bougie should be coffee brown. but when your letting it run idle(stationair) your color will change so u cant totally depend on the color if u havnet driven a long while with it.