Fuel filter on micron size?

Not all 4 strokes are created equal. I could say 150 micron is the norm but what does that even mean? Some higher end models could use 60 micron fuel filters. But then again what does that mean? The design of the filter matters as much as its porosity. As far as grade and additives that is best left up to the manufacturer of the engine itself. A higher grade may be perfect for manufacturer X but that same grade may cause manufacturer Z's engine to become too hot.

A micron is 1 millionth of a meter, or .00003937 of an inch. The micron rating of a filter determines the particle size able to pass through it. Different engine manufacturers recommend the micron rating for filters used on their units. Sometimes it's ppm, or particles per million, referring to contaminants of a certain volume. For example, gasoline engines can run on larger particles if their carbureted, where injectors will not accept them. The viscosity of liquids being filtered also determine micron ratings. Luckily the filter manufacturers did all the engineering for us and know what to supply for each system. So I try to always buy a good name brand filter. Unfortunately small engine filters are usually just a screen with unknown mesh size and we use them because their small and convenient. I recently started buying leaded higher octane fuel for my motorbicycles and immediately they run better and idle smoother. My hoses stay more flexible, it doesn't ruin the paint on my tanks, they start easier and get better mileage. I use sediment bowls on some of my bikes with good results, but I also like a valve with an internal screen to keep from sending debris from the bottom of the tank to my engine. Hope this all makes sense.

Higher micron rating means larger holes in the media and less filtering, where higher mesh rating means smaller holes and more filtering.