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.
Step 1 = trimming the original filter-holder http://www.cafehusky.com/threads/pottering-around.39580/page-2#post-410742 Step 2 = replaced the initial pantyhose material with a poolfilter sock (denser mesh) sprayed with a bit of air filter oil 5 filter pack from the hardware store @ ~$6.50 Step 3 = re-insert OEM air-filter "drawer/ holder" as per usual. Edit: oops, just saw Nev's already replied in the meantime.
One of the finest examples of parts bin engineering I have seen. Really nice work. I modded my filter to fit a BMWF800R cleanable filter. To be honest this is prob adequate as a filter, let alone a pre filter
Important to some :L You don't even have to touch the dirty filter. Just peel up one corner of the pool sock, lift and dump in the bin. At ~$1each and the 5-minute job done every 2-3000km, one might only have to check the Pod filter every 10.000 or so.
And the irony is that because of the OEM filter cover mounting, removing the filter door to replace the pre-filter is way more difficult than getting to Pod filter in the airbox. I have ditched two of the bolts holding the filter door on. I have mine only held on by the top bolt. I haven't really noticed any dust getting in past that door. I got a biro, cut about 1/2" off the tube, bought a hex bolt about 1/2" longer (I think I ended up with a 40mm bolt) than the originals for the filter door, and use the biro tube as a spacer.
