Sprint Filter P08 Air Filter for Road & Track – Kove NK321R (2021–2026) PM242S

The NK321R and the faired 321RR share this part number, which tells you the airbox is common to both. What is not common is the working week. A naked machine of this size is the one that gets used on Tuesday morning as well as Sunday afternoon: short trips, traffic, cold starts, kerbside parking, the whole unglamorous duty cycle that decides how a filter element actually ages. Grit from a city road arrives in small daily instalments rather than in one memorable dust cloud, and it is that steady arrival, not any single dramatic event, that this element is answering.

Key Features

• Dry polyester weave rated at 80 microns — the same medium Sprint Filter specifies for road and circuit use
• Published flow figure of 5,050 l/m²/sec for the material itself
• About double the filtering area of a comparable performance element, achieved by the pleat geometry rather than a bigger box
• Completely dry in service: no oiling step to remember, none to get wrong
• Cleaned and refitted rather than thrown away, for as long as the motorcycle lasts
• Covered by a two-year guarantee

The maintenance item you are most likely to skip

Filters get neglected because nothing announces their condition. A commuting machine collects its dirt gradually and gives no signal at any point along the way; the first evidence is usually a service invoice with a new paper panel on it. Swapping to a washable element changes the shape of that problem rather than the physics of it — the job becomes fifteen minutes with an air line instead of a parts order, which is precisely the kind of job that actually gets done. To be clear about what it buys: intake resistance that is lower and, more usefully, that stays where you put it between cleanings. It does not make a standard NK321R noticeably more powerful, and any description that says otherwise is selling something.

Why nothing here is oiled

Oiled cotton gauze works by wetting the fibres so particles stick. It filters well when freshly serviced and it depends entirely on that service being done correctly, with the right quantity, evenly, and left to cure. Get it wrong on a modern fuel-injected machine and the surplus has somewhere to go — forward, into a tract full of sensors. The Sprint Filter approach removes the variable rather than managing it: the polyester is dry when it leaves the factory and dry every time it goes back in.

Care and cleaning

Blow the PM242S through from the clean side outwards with compressed air, which reverses the path the dirt took getting in. Heavier deposits come out with warm water and a mild detergent, followed by a thorough rinse. Let it dry in still air on its own time; heat and open flame will damage the weave and are never appropriate. Fit it dry. The maintenance instructions are available under the Downloads tab.

Fitment & Compatibility

Covers the Kove NK321R from 2021 to 2026, fitting the standard airbox with no changes. Two machines use this element in total, the NK321R and its faired 321RR sibling; the Fitment tab carries the full list.