nev..
Terrarist
Hi Nev,
Could you please post a few pic's of your Pre-Filters. And maybe a brief description of how they fit inot the bike.
Thanks!
glitch_oz must take all credit because this is his solution.
First the stock air filter holder is trimmed down.

This is to allow for the fact that there is now a crankcase breather pod also sharing the space inside the original air filter space.

The pre filter is a swimming pool filter designed for the skimmer basket. These cost about $6 for a 5 pack.

The sock fits over the holder quite neatly

Screw the holder door back on

and give it a squirt of filter oil before putting it back in place.
When it turns black, that one goes in the bin and a new one goes on.