I just bought two Twin Air filters to replace the stock ones I had that fell apart. I rode for the first time last weekend with the new filter a total of 50 miles in dusty conditions with four other bikes. After removing the filter today I saw a lot of fine hazy dust in the air boot, more than I would expect from any filter. I use the proper amount Maxima FFT oil and I grease the filter lip. There was no sign of lip leakage or an leak on the air boot. After pulling the filter cage you could see a dust build up on the backfire screen as the dust passed through the filter. I am wondering if the reduced size of the Twin Air could cause this by reducing the amount of foam area? Has anyone found that they have problems with the Twin Air on their WR passing dirt? I used UNI filters for years on my old bikes and never had this problem. I paid too much money to screw up my engine on crap filters. Thanks to all.