WHAT IS IT? Twin Air’s dust cover fits over your air filter to act as an air defense system that catches and knocks down dirt particles before they reach your last line of defense. By using a more porous, coarser and thinner foam, the Twin Air dust cover helps keep your actual air filter cleaner for a much longer time. This is especially valuable on sand tracks and in dusty conditions. The coarse foam acts as a pre-filter that extends service intervals.

WHAT’S IT COST? $18.95.

CONTACT? (800) 749-2890 or www.twinair.com.

WHAT STANDS OUT? Here’s a list of things that stand out with Twin Air’s dust cover.

(1) Mounting. Consider the Twin Air dust cover to be an additional stage to your existing air filter. It slips over the outside of the stock air filter, which is most likely a Twin Air anyway, in seconds. Since it is just a cover, it does not tuck around the cage, but simply encases the surface area of the filter underneath it. To install it on our 2017 KTM test bike, there were holes that aligned with the KTM filter cage pins. On a Honda, Yamaha, Suzuki or Kawasaki, it is held in place by the central mounting bolt.

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(2) Oiling. If you are racing on a dusty or sandy track, you should oil the Twin Air dust cover with the same oil filter oil you use on your primary air filter. Don’t worry about the oil making it hard for air to get into your engine—the larger pores of the dust cover flow air much more efficiently than the foam in your air filter. If you are using the Twin Air dust cover in loamy or tacky conditions, as a fail-safe you could oil it with a light coat of spray-on air or fabric filter oil or even with light-grade lubricating oil like Maxima MPPL. If you are racing on a perfectly manicured racetrack, you can run the Twin Air dust cover dry. It will still help keep your air filter cleaner

(3) Rain. Twin Air does not recommend oiling the dust cover in the rain or on a track with puddles or water crossings. Why not? The oil actually increases the water’s ability to migrate through to the primary filter. Water can dissolve air filter oil and leave spots where dirt can get attached. In rainy conditions, just run the dust cover dry.

(4) Performance. Keeping a clean filter in your bike is the most important thing you can do for the life of your engine, but it also one of the most tedious tasks. It is a messy job that is best done with rubber gloves and surgical precision. The Twin Air dust cover lessens the need for constant air-filter changes. Most MXA test riders run a Twin Air dust cover over their air filters in practice and the first moto and then remove it for the second moto. This reveals a perfectly clean filter. Because it is a thin sheet of foam, dirt particles vibrate off of it quicker than with the denser foam of your regular air filter. We confess that there are MXA test riders who leave the dust cover on for two or more races because it works well enough that the air filter beneath it is still clean. Amazingly, they don’t feel guilty about not having to clean their air filters on a weekly basis because the dust cover does a remarkable job of warding off dust, sand and dirt. A visual inspection of how dirty the dust cover is can be used to determine when to inspect your primary air filter.

WHAT’S THE SQUAWK? In tight airboxes, the Twin Air dust cover does take up more space, but we never noticed any loss of power from decreased dead air space. At $18.95, the dust cover may seem expensive, but given that you will save money on air filter oil and time changing filters, we think the price is about right. Plus, if handled carefully, the Twin Air dust cover will last for years.

MXA RATING: Considering how much riders hate the drudgery of cleaning air filters, the idea of a large pore pre-filter is a no-brainer, but not just for the chronically lazy. Using Twin Air’s dust cover for practice only, or for practice and the first moto makes sense for any racer who cares about his engine.

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