I have used my kit foam filter for all of my miles. I do occasionally rinse it out and re-oil it with 10-30 oil.
I tried a thicker foam filter, but found it to constricting so went back to the thin one.
In one instance I used cheese cloth oiled with motor oil. Works well also, the dirt sticks to the oil, when it gets to dirty to breath, throw away and re-oil some cheese cloth. Not to many layers though, these little motors like free flowing air flow.
you seem confused... dax sells engines, they do NOT manufacture them
unless you spring for a better carb or make your own filter, this is the best you're gonna get
there are a couple of filter how-to's here
do a search and check them out
i know that howell makes the engines im saying i couldnt beleve that filter, i do however love my bike now it has the engine. thanks for all ure help guys and y doesnt daxs website have a shopping cart.