Sprint Filter P08 F1-85 Air Filter for Racing – Honda CMX1100 Rebel (2021–2024) PM235S F1-85

There is a real argument for a high-flow element on a big cruiser, and it is not the one people expect. A machine of this weight, geared the way it is, is ridden with the throttle wide open far more often than a sports bike is: away from lights, up a slip road, overtaking two-up with luggage. Full throttle is ordinary here rather than exceptional. The question of what the intake costs is therefore a fair one, and PM235S F1-85 is the answer Sprint Filter offers — 85 µm of filtration at a rated 15,000 l/m²/sec, where the standard element for the same housing is 80 µm at 5,050.

Key Features

• P08 F1-85 racing weave: 85 µm filtration at a rated 15,000 l/m²/sec
• Dry polyester with no oil at any stage, so nothing is carried down the intake
• Deep pleating puts considerably more cloth inside the standard airbox volume
• Fits the Rebel housing unaltered; no cutting, no adapter, no remapping
• Cleaned with compressed air and returned to service instead of discarded
• Built for the life of the motorcycle, with two years of guarantee from purchase

Wide open, but not for long

The argument does not survive a look at how long those openings last. A flow rating is a continuous figure: so many litres per square metre per second, measured against cloth that is being drawn through without pause. What a heavy twin does is different: hard demand in short bursts, separated by long stretches at part throttle. Reserve reached for a few seconds at a time sits unused for the rest of the ride, while the five extra microns of aperture are in circuit every hour the engine runs. That is the shape of the trade on this machine, and it does not favour the racing cloth.

When it is nevertheless the right part

There is a case, and it is narrow enough to describe plainly. A machine used in a competitive or timed context, serviced on a schedule counted in running hours, and inspected by someone who opens the airbox as a matter of routine, meets the conditions the specification assumes. Under that regime a coarser weave is a supervised choice rather than a standing one. Outside it, the standard PM235S is the better answer, and choosing it is not a compromise: finer cloth holds more and passes less, a trade in both directions rather than a ladder. No element makes a standard CMX1100 stronger.

Care and cleaning

Compressed air goes on the clean face of PM235S F1-85 and pushes outward, so deposits leave the way they arrived. When air alone is not enough, hand-warm water with a mild detergent will lift the rest; rinse until clear and dry it fully in still air. No heat guns, no exhausts, no flames, and the element goes back dry with nothing applied to it. The Sprint Filter maintenance sheet is in the Downloads tab.

Fitment & Compatibility

PM235S F1-85 is listed for the Honda CMX1100 Rebel from 2021 to 2024 — one machine on this reference. The same housing takes the standard PM235S, so the fitment is settled and only the specification is open. Check the build year against the compatibility list on this page before ordering.