Sprint Filter P08 F1-85 Air Filter for Racing – Zontes ZT 250-R (2019–2021) SM277S F1-85

Three elements are catalogued for this airbox and their part numbers are almost the same. The leading characters name the housing that all of them fill; whatever trails behind names the material folded into it. On a ZT 250-R that trailing string is the entire distance between a road specification and a racing one, and it is the hardest-working detail anywhere on the label.

Key Features

• Racing specification: dry polyester rated at 85 µm, with a published flow of 15,000 l/m²/sec
• The most open medium Sprint Filter offers for this housing, and the highest flow figure in its range
• Retention measured at 95.22 % on 100-micron particles, ahead of the standard weave at 93.13 %
• Identical fit to the road element beside it: series airbox, no cutting, no adaptor, no remap
• Dry from manufacture, washed and refitted rather than thrown away, with no oil at any stage
• Specified for the working life of the motorcycle; two years of warranty from the date of purchase

The suffix is the specification

Search by model and three results come back. All of them fit, all are dry, all are washable, all carry the same warranty. Photographs will not separate them and neither will the fitting instructions. The medium does: 80 µm at 5,050 l/m²/sec for the standard weave, 14 µm at 1,800 for the nonwoven, and 85 µm at 15,000 for the racing cloth described on this page. Order the wrong string of characters and nothing goes wrong mechanically — the part seats, seals and lasts. It simply filters to a specification nobody meant to buy.

The smallest capacity on a nine-machine list

This 250 asks less of the housing than anything else the code covers; the rest of the list climbs to 350 and runs to 2026. A racing cloth is drawn for intake demand a road-registered quarter-litre machine has no way to generate, and it is catalogued at close to three times the standard element in the very same box. Nothing about the ZT 250-R argues for it, and no drop-in element makes a production motorcycle faster anyway — the useful claim is a smaller one, and it does not depend on which medium is chosen. If the airbox is being opened for maintenance rather than competition, the plain code is the correct order, and there is no shame in the cheaper suffix being the right answer.

Care and cleaning

An air line does the routine work: hold it against the clean face and drive the load back out along the path it took coming in. Where a deposit is greasy rather than powdery, lukewarm water with a mild detergent releases it, and rinsing continues until the run-off is clear. Ambient moving air is the only permitted dryer — heat guns, radiators and naked flames all deform polyester — and the SM277S F1-85 returns to the housing dry, with nothing applied to it. Sprint Filter files the maintenance sheet under the Downloads tab.

Fitment & Compatibility

Catalogued for the Zontes ZT 250-R of 2019 to 2021. Eight further Zontes machines in the 310 and 350 classes carry the identical code, nine catalogue entries in all. Confirm the year range first, then confirm the suffix.