Sprint Filter P08 F1-85 Air Filter for Racing – Bimota KB399 (2026) PM164S F1-85

The KB399 is a chassis argument rather than an engine argument. Bimota's contribution is the frame, the geometry and the suspension; the engine and its airbox come from a series-production motorcycle and are shared with ten others. That division is worth holding on to when choosing parts, because it says where the bike's limits actually are. On a machine like this the rider runs out of chassis long after they run out of engine, and an air filter is nowhere near either limit on a standard specification. The P08 F1-85 is here for the KB399 that has moved past standard: 15,000 l/m²/sec of air flow, filtration at 85 microns.

Key Features

• Straight swap in the standard airbox — no modification, no remap
• Filtration at 85 microns, a wider aperture than the road medium
• Racing medium at 15,000 l/m²/sec, roughly three times the standard P08
• Washable and reusable — the whole service is compressed air from the clean side
• Dry polyester, never oiled — nothing to reach the throttle bodies or sensors
• The warranty is two years; the element is built to last the life of the bike

Series intake, small-series everything else

There is a practical advantage hidden in that split. The parts unique to a Bimota are the ones that take time to obtain; the airbox and its element are ordinary, in production, and available on the same terms as for any of the eleven machines that share them. An owner planning to use the bike hard can stock the thinking rather than the parts — and a washable element removes even that, since it is designed to last the life of the motorcycle rather than to be reordered between meetings.

What the flow is worth on a standard engine

Nothing, and it is better to say so. The engine in a standard KB399 is not restricted by its air filter, and fitting the racing medium to it means accepting a coarser 85 micron weave in exchange for flow the engine cannot draw on. The standard P08 at 80 microns is the correct part for a road-ridden example, and the P14 at 14 microns for dusty conditions. The F1-85 earns its place once the intake path has been opened and mapped and the bike is serviced on a racing schedule — at which point it is the only one of the three that makes sense. Until then the honest place to spend on a KB399 is the half of the motorcycle Bimota actually built — tyres, suspension setup, the time to use the chassis properly. The intake is the part of this bike that came from a production line precisely because it did not need reinventing.

Care and cleaning

The routine belongs in the garage, not a counter: compressed air from the clean side, outwards, and back in dry. When a meeting has earned it, lukewarm water and a mild detergent reset it: rinse until it runs clear, then dry fully in air, never with heat or a flame. There is no oiling stage, on any of the three media. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Bimota KB399 for 2026. The same PM164S F1-85 element covers eleven machines sharing this airbox design; the complete list is in the Fitment tab.