The Racing Beat-designed Foam Air Filter Element for all 1971-85 Rotaries (except 1984-85 GSL-SE) consists of a polyurethane foam over a metal screen form that interchanges exactly with the stock element. The foam element can be re-used by periodically cleaning in solvent and re-oiling. While the element offers no significant increase in air flow when compared to a clean, stock paper element, as the paper element collects dirt its air flow capacity decreases dramatically while the foam element is nearly unaffected.