Sprint Filter P037 Air Filter for Wet Conditions – Bimota KB998 Rimini (2025–2026) PM154S-WP

The P037 is the water-repellent member of the range, and the word describes the cloth, not the airbox. Rain rarely reaches a panel through the ducting in any quantity; what reaches it is damp air, spray thrown up from the road, and the water used to wash it. A repellent finish means the weave keeps working while it is wet and gives the water back afterwards — which is precisely what a paper element cannot do.

Key Features

• Dry woven polyester with a water-repellent treatment; no filter oil is involved at any stage
• 37 microns of filtration at a rated 4,500 l/m²/sec
• Retention measured at 91.8 % of 37-micron particles — a different test from the P08's 93.13 % at 100 microns
• Roughly twice the filtering cloth of other performance elements
• Replaces the paper panel in the series airbox directly: no cutting, no remapping
• Washable and reusable for the life of the machine, with two years of warranty

Two percentages that will not line up

It is tempting to put the retention figures side by side and take the larger one. They are not on the same scale. The 91.8 % quoted here was measured against 37-micron particles; the 93.13 % quoted for the standard weave was measured against 100-micron particles. A finer challenge is a harder test, so the smaller number does not describe a coarser filter, and the two cannot be subtracted from one another. What can be compared without ambiguity is the specification itself: 37 microns against 80, at 4,500 l/m²/sec against 5,050 — a substantial gain in retention for a modest reduction in flow.

Wet weather as a maintenance question

A paper panel that has been through heavy rain does not come back. The fibres swell, the pleats lose their shape, and whatever resistance it gained it keeps until it is thrown away. That is the case this medium answers: washing belongs to the routine here rather than being a repair, and the element returns to service when it is completely dry. None of which is a power claim. An element in an unmodified airbox does not make a standard KB998 Rimini noticeably stronger, and this one trades a little flow against the standard weave in exchange for finer retention.

Care and cleaning

Start with an air line held to the clean face of the PM154S-WP and directed outward. For a wash, use lukewarm water and a mild washing-up detergent and rinse until nothing more comes away. Then dry it by time and moving air alone — never a heater, a hot-air gun or a flame, since heat destroys the medium and the repellent finish with it. Refit it dry, with nothing sprayed on afterwards, and make sure the lid seats on its seal. The maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Cut for the series airbox of the Bimota KB998 Rimini of 2025 and 2026 and listed for that machine alone in the Fitment tab. The same housing also carries the standard P08 and the racing F1-85, both of which cover the Kawasaki ZX10R Ninja + ABS as well, and the 14-micron P14.