Sprint Filter P08 F1-85 Air Filter for Racing – Honda Grom (2021–2026) SM224S F1-85

Honda reworked this machine for 2021, and one of the changes has a quiet bearing on any conversation about intake flow: the gearbox gained a ratio. More ratios means less of the ride spent labouring between them and more of it spent in the upper part of each gear, which is where an engine draws hardest. So the newer Grom does spend a slightly larger share of its time near its peak demand than the machine it replaced. That is a real shift, and it is worth being precise about what it changes — the share, not the ceiling. SM224S F1-85 is the racing cloth for the airbox of this generation.

Key Features

• P08 F1-85 racing specification: 85 µm filtration at a rated 15,000 l/m²/sec
• Dry polyester, no oil at any point, so nothing is carried onto the intake sensors
• Deep pleating puts far more cloth into the same standard airbox volume
• Fits the 2021-onward housing unaltered — no cutting, no adapter, no remapping
• Regenerated with compressed air and refitted instead of being replaced
• Made to last the life of the motorcycle, two years of guarantee from purchase

A bigger share of a fixed number

The ceiling is set by capacity and revs, and no gearbox changes it. A 125 asks for the air a 125 can use, and the standard element for this housing already passes more than that at 80 µm and 5,050 l/m²/sec. Riding nearer the top of each gear means the engine spends longer close to its own maximum demand; it does not raise that maximum. The extra flow of the racing weave is therefore drawn on more of the time than it would have been on the earlier bike, and still not to its limit. No element makes a standard Grom stronger.

The cost side, stated once

Five microns of extra aperture is what buys the flow, and unlike the flow it is in effect continuously — at idle, in traffic, on every ride, for as long as the element stays in the airbox. That is the shape of every step across this range: finer cloth holds more and passes less, coarser cloth the reverse, and neither is a rank above the other. Where a machine is used competitively and inspected on a schedule counted in running hours, the exchange is supervised and defensible. Where it is a road bike, the standard SM224S is the better answer and the finer SM224P14 is the answer for dusty roads.

Care and cleaning

Compressed air on the clean face of SM224S F1-85, directed outward, returns most of the load to where it came from. Where more is needed, hand-warm water with a mild detergent will lift it; rinse until the water runs clear and dry the element fully in still air. No heat guns, no exhausts, no flames, and it goes back into the housing dry with nothing applied to it. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

SM224S F1-85 covers the Honda Grom from 2021 to 2026 and the MSX125 over the same years — two names, one housing. Earlier Groms and MSX125s take a different reference, so read the build year rather than the badge and check it against the compatibility list on this page before ordering.