Honda CRF 250R,450R Series (09-13) DNA Air Filter R-H4E09-0R

Yes and even better, the DNA filters have a filtering efficiency of minimum 98% (ISO 5011 test). Good quality OEM paper filters are from 97% to 99% and the foam filters are from 92% to 97%.

The percentage of dust that the filter retains during a laboratory test, following the ISO 5011 protocol.

It was brought to our attention, so we purchased the filters and tested them back to back at the same set pressure, with our DNA and the stock OEM filters. Well guess what, the data claimed were false, nothing to do with the reality! Of course the flow was higher than the stock but much lower compared to the DNA! No wonder they never compare it with the stock, as they can't claim 300% (!) increase in air flow over the stock OEM filter. Only data measured back to back the same time are comparable, don't forget we are measuring air! This is why we always publish the stock OEM data.

DNA has developed a unique filtering media that is perfect for off-road use. During the toughest rally in the world, DAKAR 2011 in Argentina - Chile, one of the factory Aprilia 450 Rally bikes, was racing with DNA filter. The results were very impressive compared to the rest of the team's bikes racing with foam filters. Every evening when the bikes were serviced, compared back to back the DNA filter and the foam filters, absolutely no dust had passed through and the engine was like new! Not to mention that one filter was enough for each day, compared to 2 or 3 foam filters per day the other bikes had to use. So this myth is busted!

Filtering efficiency is the amount of "dirt" the filter can maintain (stop) and protect the engine efficiently. For example, the DNA Filter for every 100 grams of dirt that it will receive, it will "trap" 98-99 grams, and this applies even to fine dirt as small as 5 microns.

DNA uses the most advanced computerized ROTRONICS flowbench available today. The complete procedure is computer controlled/automated, to avoid human error. Additionally, wa always test the DNA filters back to back, the same day and time, with the stock OEM filters and publish the results. Reading our data, you can immediately see the differences in air flow, between the 2 filters and what to expect by using the DNA filters.

In cases the air flow of the DNA Filter is extremely high we include with the filter special instructions.

No, you must never use the DNA filter un-oiled. The oil is a crucial part of the filtering media. You must always apply the Special DNA filter oil, not just any oil, after servicing the filter.

Race bikes must be kept always in top condition, especially the engine. Debris and flying bugs found at the track, plus rubber from the bikes' tires in front, can seriously damage the engine. DNA will provide the maximum air flow and at the same time maximum protection. We do not compromise filtering efficiency in order to increase flow; we increase air flow using our revolutionary FCd design, maintaining the 4 layer reliable DNA filtering media. If you want the highest air flow and filtering efficiency of 98% for your race engine, then your only choice is DNA.

The servicing intervals depend on the environment that the vehicle is used. Once a year or every 15.000 to 30.000 km is suggested, to keep your DNA filter in top condition. An easy way to check if the filter needs cleaning, is to see if the wire mesh that that is on the dirty side, is visible.
If you can see the mesh, you can continue using the filter. If the mesh is totally covered in debris, you must clean the filter.