Bill, those tubes hold another part in there, it looks like a bushing and it's for the needle. You should see a little bit of it sticking through the carb bore, right smack dab in the middle. They just push out. New ones come with new needles. (That's why it's called a needle kit. One needle, bushing and E clip.) If you already knew this, my apologies for insulting your intelligence!
Twostrokecrazy