Sprint Filter P08 F1-85 Air Filter for Racing – Honda CB400X (2019–2026) CM220S F1-85

The word Racing in a part name is a description of intent, not a certificate. Nothing about the P08 F1-85 is homologated, approved or type-tested for road use, and nothing about it needs to be: it is a filter element that sits inside the standard airbox of a Honda CB400X and changes nothing a technical inspection looks at. No bodywork moves, no exhaust changes, no mapping is touched, and the airbox keeps its original lid, inlet and volume. What changes is the fabric inside it — a dry polyester racing medium flowing 15,000 l/m²/sec at a filtration of 85 microns, where the road-going P08 flows 5,050 at 80.

Key Features

• The racing medium: filtration at 85 microns, air flow of 15,000 l/m²/sec
• Dry polyester with no oil in it, so no film can reach a hot-film sensor or the throttle bodies
• The medium presents about twice the filtering area of a normal performance element
• Sits inside the standard CB400X airbox — nothing modified, nothing remapped, nothing to declare
• Cleaned from the clean side with compressed air, washed when needed, used again
• Two years of warranty on an element designed to last the life of the motorcycle

An internal change, and therefore a reversible one

Because the element is entirely inside the airbox, the CM220S F1-85 leaves no trace on the outside of the motorcycle and no entry in any document. It can be taken out and the original element put back in an afternoon, which is worth knowing for a bike that might be sold, inspected periodically or ridden in more than one country. That is a practical point rather than a legal opinion — rules on modification differ by market, and the responsibility for what is fitted stays with the owner. It is simply true that this particular change is internal, reversible and invisible.

Whether it belongs on a CB400X at all

Being honest about it: the X is the touring-shaped member of this family, and the racing medium is not the obvious choice for it. A bike used for distance on public roads meets more dust than a circuit does, and the F1-85's wider aperture is the wrong direction for that. The standard P08 covers road and track sensibly, and the P14 at 14 microns is the one for dusty routes. The F1-85 earns its place on a CB400X in one situation: when the bike has become a track machine, is serviced on a race schedule, and its engine is already breathing through more than the standard intake.

Care and cleaning

No oiling stage exists for this medium, out of the box or after a wash. Compressed air from the clean side, directed outwards, is the standard service. When a hard weekend has earned it, lukewarm water with a mild detergent, rinsed until the water runs clear, then dried right through in moving air; never with heat, never with a flame. It goes back in dry. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Honda CB400X from 2019 to 2026. The CM220S F1-85 covers six machines across Honda's 400 and 500 twin range from one shared airbox design; the complete list is in the Fitment tab.