Sprint Filter P14 Air Filter for Dusty Conditions – Honda GB350 / GB350S (2021–2026) SM289P14

A GB350 is very often the only motorcycle in the household: the commute, the errands, the family visit and the weekend all fall to the same machine. That has one consequence for the choice of filter medium that gets overlooked. The element is a standing decision, taken once and then left to cope with every kind of air the bike happens to meet — nobody swaps media at the roadside when the surface turns to gravel or the road runs alongside a field being harvested. The sensible basis is therefore not the average day but the dirtiest week of the year, provided the engine has flow to spare. A 350 cc single does, which is what makes the Sprint Filter P14 SM289P14 defensible here at 14 microns instead of the P08 weave's 80.

Key Features

• Dry special non-woven, filtering to 14 microns, with no oil involved at any stage
• Where the standard P08 weave passes 5,050 l/m²/sec, this one is rated at 1,800 — retention bought with air
• Around double the filtering surface of other performance elements
• A straight swap in the standard airbox: no modification, no remap, homologation unaffected
• Blown clean from the clean side and put back in — the element is reused, not replaced
• A two-year warranty runs from the purchase date

Averages hide the week that does the damage

Dust does not arrive evenly across a year. Months of clean, damp tarmac can put less through an element than a single fortnight behind roadworks, on a dry track to a campsite, or on a road bordered by fields in late summer. Because the medium cannot be matched to the day, it has to be matched to the worst conditions the bike is genuinely expected to see. A machine used for everything meets those conditions sooner or later, and it meets them without warning.

What that costs, and when it is the wrong answer

The finer medium is not a free upgrade. Retention and flow move against each other: a tighter path holds back more and passes less air per square metre per second, 1,800 against 5,050. Neither figure makes one filter better than the other — the P08 is aimed at road and track air, this one at dust. On a GB350 or GB350S the trade lands well because the engine never asks for the P08's reserve, while the dust is real. If the bike is ridden mostly on clean sealed roads at a decent pace, the P08 is the more balanced choice and this is the wrong page.

Care and cleaning

Compressed air, from the clean side, blown outwards: that is the service most weeks. For anything heavier, lukewarm water with a mild detergent, rinsed until the water runs clear, and then open air until the element is properly dry — heat and flame both ruin it, so neither goes near it. It is refitted dry, since the SM289P14 has no oiling stage. Sprint Filter’s maintenance sheet is in the Downloads tab.

Fitment & Compatibility

Made for the Honda GB350 and GB350S from 2021 to 2026. The same SM289P14 element covers five machines built around this 350 cc single; the complete list is in the Fitment tab.