If you take off your K&N and look closely through the 3 mesh layers
(there's no foam) you will note that you can see between the wires. How
well can this filter small particles? It may keep out coarse sand, but dust
can go straight through.

Use them at your own risk! There's no way K&N will pay for your worn-out
bores/pistons/bearings etc (dust will get past the rings into the cases and
therefore the oil as well).

I ran a Honda 750 Four/900 without filters, only velocity stacks (I bought
it that way, and when I put filters on it the VW-style head oil leaks
coated and clogged them; the oil would collect in the W-section alloy back
wheelrim and when I stopped it would pool at the bottom and overflow onto
the ground!). That bike was FAST, but yes, the bores wore.

Andrew Grebneff
Dunedin, New Zealand
VW & mollusc nut
1984 VW Caravelle (currently SVX engine; waiting for a Porsche trans)
1985 Mitsubishi Galant Sigma 2.0 (FWD), for sale
1986 CE80 Toyota Corolla 1.8DX diesel (extaxi)
1989 CE96 Toyota Corolla 1.8DX diesel wagon
1989 CT170 Toyota Corona Select 2.0 diesel (taxi)