air relief in filter

[CHR!S/DVK]

i recently got myself a set of original kadron air filters and noticed that one of the bottom parts of the housing has an air relief tube(see picture).
as this bottom is a selfmade part i would like to replace it by an original one.
the replacement part i found doesn't have this air relief tube.

my question is, what i the use of this air release? is it meant to be connected to a breather box?
i have seen other air filter which had it.
is it essential, so that i cannot replace it by a disclosed original one?

[Bruce]

That tube is meant to connect to the stock vent at the oil filler.  If you have that vent connected to your breather box, connect it to your air cleaner.

[CHR!S/DVK]

That tube is meant to connect to the stock vent at the oil filler.  If you have that vent connected to your breather box, connect it to your air cleaner.

thanks for you reply bruce, the air cleaner on my stock carb is also connected to the vent of the oil filler, but is this connection essential?

[Diederick/DVK]

this fitting is often seen on IDFs and DRLA carb that run air filters.

and doesn't your breather box have 4 fittings?
i'd say left rocker cover, oil filler, right rocker cover, right side air filter, bro. it would allow you to hook things up nicely tucked away, too!

[Zach Gomulka]

You don't "need" it, but it may help prevent oil from exiting the crankcase at the pulley.