Sprint Filter P037 Air Filter for Wet Conditions – Yamaha YZF-R3 (2015–2026) K44S-WP

Read the installation line before anything else on this page. The K44S-WP is not a panel that changes places with the original: the catalogue records that it requires modification of the airbox, with the housing repositioned to receive it. That single line moves the part out of the category of Saturday-morning servicing and into the category of preparation — something done once, deliberately, by someone who has already decided what this YZF-R3 is going to be used for.

Key Features

• Water-repellent woven polyester, used dry, rated at 37 microns
• Rated throughput of 4,500 litres per square metre per second
• The repellency belongs to the cloth: nothing is sprayed on it and nothing is oiled
• Roughly double the filtering surface of other performance filters
• Fitting requires the airbox to be repositioned — allow for that work before ordering
• Washable, reusable, and warranted for two years from the date of purchase

What repellency is answering

A wet element is not simply a dirty one. Water taken up into a medium changes the restriction while the machine is being ridden, and it changes it in the unhelpful direction at the moment the weather is at its worst. A repellent weave addresses precisely that: the cloth sheds water instead of holding it, so the resistance a rider has on a soaked motorway stays near the one measured dry. It is a weather part. No element of any kind, in this housing or any other, makes a standard R3 noticeably stronger — what this one offers is an intake restriction that does not climb when it starts to rain.

A retention figure that belongs to a different test

Sprint Filter quotes 91.8 per cent retention for the P037, and it is worth saying plainly what that number is. It was measured with 37 micron particles, while the 93.13 per cent published for the standard P08 was measured with 100 micron ones. Two tests, two particle sizes, and no arithmetic that runs between them: the smaller percentage here does not describe a coarser filter. The figures that do compare directly are the ratings themselves — 37 microns against 80, and 4,500 litres per square metre per second against 5,050.

Care and cleaning

Servicing the K44S-WP is dry work despite the name. Compressed air on the clean face, worked outwards, is the routine. Water and a mild detergent lift what air leaves behind, rinsed until it runs clear — the cloth sheds water, it is not harmed by it. Drying happens in open moving air only, never with a heat gun, a radiator or a flame, and the element goes back in dry and untreated. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Listed for the Yamaha YZF-R3, model years 2015 to 2026, and for that machine alone. Because the installation involves repositioning the housing, measure the job against your own motorcycle before ordering; the Fitment tab carries the model years.