Sprint Filter P08 F1-85 Air Filter for Racing – Honda CB400 Revo / Super Bol d’Or (2008–2026) OM184S F1-85

Racing, on this listing, is the name of a material grade. It is not an eligibility or a class: no championship is run for this 400, and no scrutineer will ever look at the cloth inside its airbox. What the designation records is that OM184S F1-85 is woven to the specification Sprint Filter supplies for racing use — 85 µm of filtration and a rated 15,000 l/m²/sec, against 80 µm and 5,050 l/m²/sec for the standard element in the same housing. The material arrives with the context stripped out. The buyer has to put it back.

Key Features

• P08 F1-85 racing weave: 85 µm filtration at a rated 15,000 l/m²/sec
• Dry polyester throughout, with no oil to be drawn downstream
• Deep pleating puts far more cloth into the same standard airbox volume
• Fits the CB400 airbox with nothing altered and no remapping required
• Serviced with compressed air and returned to use rather than discarded
• Built to last the life of the motorcycle, two years of guarantee from purchase

What the label assumes about the owner

A racing weave carries an assumption with it: that the airbox is opened often, on a schedule counted in running hours, by someone who inspects rather than waits. That assumption is what makes five extra microns of aperture a supervised decision instead of a standing one. Where it holds, the exchange is deliberate — flow bought, filtration given up, both quantified on the same data sheet. Where it does not hold, nothing about the cloth changes; only the supervision disappears, and a coarser filter stays in a road bike for the whole of its life. No filter makes a standard CB400 stronger, and this one is not sold on that claim.

Reading the step in this listing

Set against the standard element for this housing, the racing cloth here is close to four times the price — the steepest step of any Honda family in the catalogue. Sprint Filter prices the racing weave at almost the same level across the whole range, while the standard element moves with the size and shape of the housing it fills. This box takes the least expensive standard element in the brand’s listings, so the ratio is large chiefly because its base is small. The cloth is the same cloth Sprint Filter sells for every other machine.

Care and cleaning

Regeneration is dry work. Compressed air goes on the clean face of OM184S F1-85 and pushes outward, so deposits leave the way they arrived rather than being driven into the weave. When air alone is not enough, hand-warm water with a mild detergent lifts the rest; rinse until clear and dry it fully in open air. Heat guns, ovens, exhausts and flames are off limits, and it goes back in dry. The maintenance sheet from Sprint Filter is in the Downloads tab.

Fitment & Compatibility

OM184S F1-85 is listed for the Honda CB400 Super Four (1998–2006) and the CB400 Revo / Super Bol d’Or (2008–2026) — two machines, one housing, one reference. The same box also takes the standard OM184S and the finer OM184P14: the fitment is settled, only the specification is open. Check your build year against the compatibility list before ordering.