Sprint Filter P14 Air Filter for Dusty Conditions – Honda CB350RS (2020–2026) SM289P14

The RS is the version of this family that leaves the tarmac: block-pattern tyres, an upright seat, and owners who take unsealed roads because the bike invites it. What matters for a filter is that a dust cloud is not one substance. The coarse grit a wheel throws up is heavy enough to fall back out of the air within seconds, while the fine fraction stays in suspension and drifts. The dust an airbox actually meets is therefore weighted towards the small end of the range — which is precisely the end a coarse medium passes. That is the case for the Sprint Filter P14 SM289P14 on this model: 14 micron filtration where the standard P08 weave works at 80.

Key Features

• Minutes with a compressor and it is done — no oiling kit in the luggage, no drying time to wait out
• Rated at 14 microns, a dry special non-woven, and never oiled, so nothing can travel downstream
• 1,800 l/m²/sec against the P08’s 5,050: finer medium, more held back, less air through
• Roughly twice the filtering area of other performance elements
• Goes straight into the standard airbox — no modification, no remap, homologation as it was
• Built to see out the motorcycle’s service life

The part of the cloud you cannot see settling

Watch a vehicle leave a gravel road and the visible plume drops away quickly. What remains hanging is the material light enough to stay airborne, and it is still there when the next rider arrives. Sitting in traffic on a dry unsealed surface, or riding at the back of a group, an engine breathes mostly that lingering fraction rather than the shower that fell out of the air long before. A medium chosen against the dust you can see is being chosen against the wrong sample.

The exchange, stated plainly

Retention and flow always move in opposite directions. A 14 micron non-woven presents a tighter path than an 80 micron weave, and a tighter path passes less air per square metre per second: 1,800 against 5,050. Neither medium is better than the other, they are aimed at different air. What makes the trade sensible on a CB350RS is that a low-revving 350 cc single never calls on the flow the P08 holds in reserve, so the reserve is not something the rider loses — while the dust on a farm track is very much something the rider meets. The other side of it: a finer element loads faster, so on a gravel season look at it more often rather than waiting for the service book.

Care and cleaning

One pass with compressed air from the clean side, working outwards, puts most gravel-road dust back where it came from. When that is not enough, wash the element in lukewarm water with a mild detergent and rinse until the water runs clear. Then leave it in open air until it is dry through — no heat, no flame, no shortcuts — and refit it dry. The SM289P14 has no oiling step, and neither has any Sprint Filter medium. The maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Honda CB350RS from 2020 to 2026. The same SM289P14 element covers five machines built around this 350 cc single; the complete list is in the Fitment tab.