I did some research on fuel filters, and micron filtration sizes. It was... Interesting.
Some sources claimed that fuel filters should be rated to catch down to 20 microns (diesel applications), others stated that 70 microns was sufficient. Then there was one that discussed using two filters, with the primary catching 20 microns, and the secondary catching particles as small as 2 microns! [This extreme level of filtration seemed to only apply to boat engines, which needed that high level of filtration due to water contamination issues -- don't ask...]
Never mind the filter efficiency rating issue.I came away thinking that any fuel filter that is rated at 70 microns, is likely good enough for motorcycling (paper media, surprisingly, is usually rated at
70 microns -- I thought paper was one of the best/finest filter medias to use... I was wrong), and anything rated to catch smaller than 20 microns, will need two filters, and that is more than I want to bother with. I found one source that stated fuel injection systems, on cars, only filter down to 70 microns, and it
implied this was finer than what a carburetor system would need?
When I looked up some filters I have at home, I could not find a micron rating for them. From what I read, it is a complicated thing, requiring high-$ equipment to determine the micron size a given media will catch, and how efficiently (they use glass beads, of a known size, counting how many, of each size, slip through). If they don't publish it, it might be a good idea to send the manufacturer/seller a question on the micron rating, and efficiency of his product, or move on to another filter... You could also try your luck, and see what happens. Like I said, paper media is typically rated at 70 microns (good enough for 50 PSI fuel injection systems). As always, YMMV. Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII