BMC FM636-04 Air Filter. BMC Replacement Air Filter The know-how gained on the racetracks is directly incorporated into the production of the series filters. To offer the discerning motorcyclist a product that is tried and tested, delivers performance and is in a constant state of evolution. Made from the best materials that are currently available on the market. The filters are made from a single rubber frame to prevent any breakage. The filtering element is made of a special cotton fabric (4 layers) soaked in a low-sticky oil. It is encased in an aluminum mesh treated with an epoxy solution to make it resistant to gasoline fumes and oxidation. Furthermore, cotton has the advantage of being washable and reusable. These features guarantee that BMC sports air filters (replacement air filters) offer a higher airflow compared to the original paper filters, minimal pressure loss of the incoming air, and thus lead to better engine performance. Maximum air permeability (4 layers of cotton) – Higher absorption and filtration – Improved pressure drop ratio – Tested using international testing procedures. 1x BMC Air Filter. Product Type: Air Filter. You can send us a message by using the “Questions and answers” section towards the bottom of the page.