Animated service guide
Dirt Bike Air Filter Service, Animated
The oiled foam filter is the only thing between trail dust and your piston, rings and valves. Fine dust that gets past a dry, torn or badly sealed filter wears the top end from the inside. Clean it, oil it, grease the rim and lock it in place. Fitting a new filter uses the same oil and grease steps.
The animated guide loads here. Every step is also written out below.
Looking for the full article? How To Clean A Dirt Bike Air Filter: Step By Step From The Manuals covers this job in depth. This page is the animated, step-by-step version used in the MotoMind app.
Before You Start
Tools
- Two tubs or buckets
- Rubber gloves
- Plastic bag
- Clean rags
- Soft brush
- Intake cover or a clean rag to block the intake
Parts And Supplies
- Foam filter cleaner
- Foam filter oil
- Grease for the sealing rim
- Spare or new filter if yours is damaged
Safety
- Never clean the filter with gasoline. It damages the foam and glue, and Honda warns of fire and explosion.
- Never start the engine with the filter out.
Step By Step
Clean around the airbox
Wash the bike first, but keep water away from the intake. Then brush loose dirt off the airbox and seat area before you open it, so nothing falls in when the cover comes off.
- Soft brush
- Rag
Careful. Honda says not to point water at the air cleaner. Water in the airbox can get into the engine.
Pull the filter, block the intake
Take off the airbox cover, release the retaining tab or bolt and lift the filter out with its cage. Pull it straight out so dirt on the outside doesn’t drop inward. Block the intake right away with a cover or a clean rag.
- Intake cover or clean rag
Shop tip. Pull the filter and look at the grease on the rim before you wipe anything. A track of dirt through the grease shows exactly where it leaked.
Inspect the foam
Look over the whole filter for tears, holes and seams coming apart. Squeeze it gently and check it springs back. A torn filter goes in the trash, because a split seam is a straight path to the engine.
How often Bike Spec Source KTM / Husqvarna / GASGAS SX, SX-F, XC, TC, FC, MC, EX (race) Every 15 h KTM 450 SX-F 2024 owner’s manual, PDF p. 41 and p. 28 (also every 24 months); KTM 250/300 SX and XC 2024 OM, PDF p. 36 KTM XC-W, EXC, 450 / 500 EXC-F, XCF-W, XW-F, Husqvarna TE (enduro) Every 15 h Also every 24 months, XW-F included. KTM 250 XC-W / 300 EXC / 300 XC-W 2026 OM, PDF p. 55; KTM 450 XCF-W / EXC-F 2025 OM, PDF p. 54; Husqvarna TE 250/300 2026 OM, PDF p. 55 Yamaha YZ / YZ-F (race) Every race (2.5 h) Yamaha YZ250F 2026 owner’s service manual, p. 3-3 Honda CRF-R (race) Each race (2.5 h) Honda CRF250R 2025 owner’s manual, maintenance schedule note 1 (RX about 3.5 h per race; after every moto in dust) Honda CRF450X, CRF250F, CRF125F, CRF110F (trail) 600 mi or 6 months Non-competition schedule, more often when wet or dusty. Honda CRF450X 2025 owner’s manual, PDF p. 45 and 47; CRF250F 2025 OM, PDF p. 51 to 52 Honda CRF450RL (on-road schedule) 600 mi or 4 months More often in wet or dusty areas. Honda CRF450RL 2025 Off-Road Handbook, PDF p. 37 Use your manual as the longest gap. In dust or sand, clean it after every ride.
Shop tip. Rotate two or three filters. Clean them all at once, oil them, and keep the spares sealed in bags so a fresh one is always ready.
Check the clean side and the boot
Look inside the filter cage and wipe the intake boot with a clean finger or white rag. Dirt only on the outer foam means the filter did its job. Dust inside the boot means air got around or through the filter, so find out why before you ride again.
Shop tip. If you find dust in the boot after a long dusty ride, a compression or leak-down check against your own baseline tells you if the top end paid for it.
Wash it in filter cleaner
Soak the filter in foam filter cleaner and work the dirt out by squeezing it under the surface. Change to clean cleaner if the first tub turns to mud. Then rinse it the way your cleaner’s instructions say.
- Foam filter cleaner
- Two tubs
- Gloves
What to wash it in Bike Spec Source KTM / Husqvarna / GASGAS Filter cleaning liquid KTM 450 SX-F 2024 owner’s manual, PDF p. 82 Yamaha YZ / YZ-F Filter cleaner or kerosene Yamaha YZ250F 2026 owner’s service manual, p. 3-17 Honda CRF-R No gasoline or solvents Honda 2004 CRF450R owner’s handbook, air cleaner service Use a foam filter cleaner. Never gasoline or low flash point solvent.
Careful. Never use gasoline. KTM, Yamaha and Honda all say it damages the foam or the glued seams, and it is a fire risk.
Press it out, never wring
Squeeze the filter between your palms to push the cleaner and water out. Never twist or wring it. Twisting tears the foam and splits the glued seams. Let it dry completely before you oil it.
- Clean rag
Shop tip. Twin Air says not to speed up drying with compressed air or a hair dryer. Give it time, or swap in a spare that is already done.
Oil it in a bag
Put the dry filter in a plastic bag, pour in foam filter oil and knead it through the bag until the foam is one even color with no dry patches. Press out the extra in a clean rag. It should be wet but not dripping. Oil a brand new filter the same way.
- Plastic bag
- Foam filter oil
Filter oil Bike Spec Source KTM / Husqvarna / GASGAS Foam filter oil KTM 450 SX-F 2024 owner’s manual, PDF p. 82 Yamaha YZ / YZ-F Foam filter oil Yamaha YZ250F 2026 owner’s service manual, p. 3-17 Honda CRF-R Pro Honda Foam Filter Oil Honda 2004 CRF450R owner’s handbook, air cleaner service Use an oil made for foam filters, not motor oil or gear oil.
Careful. Too much oil makes the bike run rich and hard to start. Too little lets fine dust straight through.
Clean the airbox, check the boot
Wipe out the inside of the airbox, working dirt away from the intake. Check the intake boot and its clamp for cracks, splits and a tight fit, because a crack after the filter lets dirt in unfiltered.
- Clean rag
Grease the sealing rim
Spread a full, even ring of grease on the filter’s sealing rim, the face that seats against the airbox. The grease fills any gap so air can’t sneak around the foam.
- Grease
Sealing rim grease Bike Spec Source KTM / Husqvarna / GASGAS Long-life grease KTM 450 SX-F 2024 owner’s manual, PDF p. 83 Yamaha YZ / YZ-F Lithium-soap grease Yamaha YZ250F 2026 owner’s service manual, p. 3-18 Honda CRF-R White lithium grease Honda 2004 CRF450R owner’s handbook, air cleaner service Use the grease your manual names. A light colored grease shows any dirt that got past.
Shop tip. Honda’s old handbook suggested white grease for a reason. Any dirt that gets past the seal shows up as a dark track at the next clean.
Refit it and lock it
Pull the intake cover out, then seat the filter on its cage with any markings facing up. Lock the retaining pin, tab or bolt so the rim presses evenly all the way round. Refit the airbox cover and any breather hose that routes through it. In dust, check far more often than the schedule. KTM says about every 30 minutes, and Honda says clean it after every moto.
Use the how often from the table above.
Careful. KTM warns that a filter not mounted correctly lets dust and dirt into the engine. Check the rim is seated before the cover goes on.
Sources
Log It And Know When It Is Due Next
MotoMind logs engine hours and every service job with notes, parts and cost, and shows each task as upcoming, due or overdue. Available to download on iOS.
