Air Filter Cleaning – Replacement Guide for 2019 KTM 150SX

Shop parts for a 2019 KTM 150SX Dirt Bike.

The 2019 KTM 150SX is a high-performance two-stroke motocross bike designed for aggressive power delivery and precise handling. Regular air filter maintenance is absolutely essential to keep the engine running at its best and to prevent costly engine damage caused by dirt or dust ingestion. This guide, tailored to MotoSport.com customers, will help you properly clean and replace the air filter, with specific considerations for the 2019 KTM 150SX.

Unique Features of the 2019 KTM 150SX Air Filter Setup

  • Tool-free access: The 2019 KTM 150SX features a straightforward air filter removal system—just loosen a single long seat bolt, slide the seat back, and access the filter. The filter itself is held by two grommets and can be released with a simple pull; no tools required once the seat is off.
  • Quick-release filter cage: The KTM's air filter is mounted on a plastic cage designed for rapid removal and installation.
  • OEM recommended cleaning interval: KTM recommends checking and cleaning your air filter after every ride in dusty or muddy conditions for optimal performance and maximum engine life.

Step-by-Step: Cleaning or Replacing Your 2019 KTM 150SX Air Filter

Preparation

  • Park on a stand and let the bike cool completely.
  • Have latex gloves, air filter cleaner (petroleum- or biodegradable, matching the type of oil used), clean water, quality air filter oil, and a replacement filter if needed.

Removing the Air Filter

  • Loosen the single seat bolt found at the rear, then slide the seat back and lift it off to expose the air box.
  • Pull the air filter cover free from its two grommets.
  • Release the filter cage tabs and carefully remove the air filter to avoid dirt dropping into the air boot.
  • Inspect the filter and cage for rips, tears, or excessive wear. Replace if damaged.

Cleaning the Air Filter

  • Use a cleaner appropriate for the oil type on your filter: petroleum-based or biodegradable. Immerse the filter in the cleaning solution and gently massage to dissolve dirt and old oil.
  • Rinse the filter thoroughly with water and let it dry completely. Never wring or twist the foam aggressively, as this can damage it.
  • Clean the filter cage and air box with a suitable contact cleaner, wiping out all debris before reassembly.

Re-Oiling the Filter

  • Once dry, generously apply high-quality air filter oil throughout the foam, massaging it in to ensure total coverage. The filter should be uniformly blue or red, depending on the oil used—with no dry patches.
  • Install a bead of air filter grease at the filter’s sealing edge for extra protection and to prevent dust bypass.

Reinstallation

  • Reinstall the filter on the cage, ensuring it seats snugly with no gaps.
  • Reattach the filter and air box cover to the bike, then reinstall the seat and tighten the bolt.

Special Notes for 2019 KTM 150SX Owners

  • Never run the bike without a properly oiled air filter—this risks catastrophic engine damage.
  • Always inspect for any signs of intake boot leaks or poor filter seal. The KTM design makes this check straightforward during every filter service.
  • Use only high-quality, compatible filter oil. Using the wrong type can reduce filter efficiency or increase risk of airflow restriction.
  • Keep a spare, pre-oiled filter on hand for quick turnaround during race weekends or multi-day outings.

How Often?

In dusty or muddy conditions, clean the air filter after every ride. For moderate conditions, cleaning every two to three rides can suffice, but make it a habit to visually check after each ride—especially after motos where air filters see heavy exposure.

Proper air filter maintenance is the easiest way to protect your 2019 KTM 150SX’s engine and maintain peak performance. For all air filter parts, cleaners, and OEM replacements, rely on MotoSport to keep you riding at your best.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.