What filter is better for an (offroad) motorcycle filter if there isn't a paper type available. The only 2 options are K+N and a twin foam type filter (or stock junk). Some dirt riders claim the foam is better and others say the K+N is better.
I'd guess the oiled foam type would be better, simply because it would hold more dust before clogging. That's probably why they're so widely used on lawn mowers.....
Oiled foam is the way to go for off road. Easier to clean and they trap more dirt. All off road forums I belong to (ATV and Dirtbikes) unanimously vote for foam aswell.