Sprint Filter P08 F1-85 Air Filter for Racing – Voge Trofeo AC (2021) CM251S F1-85

Lay the four media for this airbox next to one another and something appears that cuts against instinct. The standard weave and this racing element each carry all nine machines on the housing. The 14-micron mat carries four; the 7-micron mat, five. It is the short lists that carry information: a material listed selectively has been matched to a condition somebody had in mind, whereas a material listed everywhere has merely been cut to an outline. Here, the broadest coverage is the thinnest recommendation.

Key Features

• Dry polyester with a mesh figure of 85 microns
• Rate through unloaded material given as 15,000 l/m²/sec
• Same outline as the standard part; the series airbox closes on it and the fuelling is left alone
• Retention put at 95.22 per cent in a comparison using 100-micron particles
• Around twice the cloth area of a typical performance filter
• Oil-free for its whole life, serviced with an air line, two-year guarantee

Two figures, pulling apart

They move in opposite directions and by wildly unequal amounts. Five microns of extra opening buys a rate three times higher, so the pair cannot be collapsed into one quality score. Nor does the published retention settle anything: 95.22 per cent is a result against particles bigger than either opening, which describes behaviour at the coarse end and says nothing about the fraction where the difference in mesh would actually appear. A single test at a single particle size is not a league table.

The case for this particular bike

Slim, and better admitted. The extra rate is only called upon with the throttle held open and the engine working near the top, which is a small slice of what a Trofeo AC does, while the wider mesh stands open through all of it. The element asks a little under two and a half times what the standard weave asks and expects paddock servicing habits in return. And nothing that drops into a series airbox makes a series motorcycle noticeably stronger — this included.

Care and cleaning

An air line across the clean face, pushing outward, is the routine; on a circuit that means between outings rather than between services. Film that stays put lifts in lukewarm water with a drop of mild detergent, rinsed until the run-off stops clouding. Drying is patient and cool — moving air, nothing warm, no flame — and the CM251S F1-85 is refitted dry and bare. Its maintenance sheet is filed under Downloads.

Fitment & Compatibility

Against the Voge Trofeo AC 500 of the 2021 model year. Nine entries share this part number across the Brivido, Valico and Trofeo families; the full list with years is in the Fitment tab.