Air Filter Cleaning – Replacement Guide for 2018 Honda CRF150RB

Shop parts for a 2018 Honda CRF150RB Dirt Bike.

Keeping the air filter clean and in excellent shape is essential in protecting your 2018 Honda CRF150RB's engine and maximizing its performance. The right maintenance ensures optimal airflow, minimizes engine wear, and helps you get the most out of every ride. This proprietary MotoSport guide covers everything you need to know about cleaning and replacing the air filter on your 2018 CRF150RB, with tips specific to this model.

Understanding the 2018 CRF150RB Air Filter

  • The 2018 Honda CRF150RB uses a dual-stage foam air filter with a thick, flat sealing ring, designed to fit precisely in the air box for optimal dirt-blocking.
  • Each filter consists of two bonded foam layers: the coarse outer catches larger grit and sand, while the fine inner layer traps finer particles, allowing for maximum airflow and engine protection.
  • This model is particularly popular among youth and lighter riders looking for punchy power and premium handling, making filter maintenance especially important to keep performance sharp.

When to Clean or Replace Your CRF150RB Air Filter

  • Clean after every ride in dusty or sandy conditions, otherwise inspect every 5–10 hours of riding.
  • Replace the filter if it shows visible wear, tears, degenerated foam, or if cleaning does not restore pliability and color.
  • Plan to clean or replace the filter more often during races, long trail rides, or after riding in wet conditions.

Tools & Supplies You Will Need

  • Replacement foam filter (OEM or dual-stage aftermarket, specifically for 2018 CRF150RB)
  • No-toil or foam-filter specific cleaner and oil
  • Clean, lint-free rags
  • Rubber gloves
  • Phillips screwdriver
  • Sealable plastic bag (for oiling)

How to Remove, Clean & Reinstall the Air Filter

  1. Remove the seat: Release the seat latch and lift it away from the frame to access the air box.
  2. Unbolt and carefully remove the filter: Use a Phillips screwdriver to remove the air filter cover. Gently pull the filter out, taking care not to knock dirt into the intake.
  3. Inspect the air box: Wipe out any loose dirt with a damp rag.
  4. Pre-clean the filter: Lightly tap the filter to remove excess dirt away from the air box opening.
  5. Clean the filter:
    • Apply filter cleaner and gently massage the foam to break up oil and grime.
    • Rinse under lukewarm water. Repeat until thoroughly clean. Never use gasoline or harsh solvents, which can damage the foam.
    • Gently squeeze (do not wring) out excess water and let the filter air dry completely.
  6. Re-oil the filter:
    • Pour filter oil into a resealable bag, add the clean, dry filter, and work oil through both layers until every part is saturated but not dripping.
    • Squeeze out extra oil and let the filter stand to allow excess to drain.
  7. Reinstall the filter: Confirm the sealing surface is clean and that the foam sealing ring sits flush with the air box to avoid dust bypass.
  8. Secure cover and reinstall the seat: Ensure all fasteners are tight and the seat is properly latched.

Pro Tips for the 2018 CRF150RB Owner

  • Always keep a spare, pre-oiled filter ready for quick swaps, especially before races or multi-day events.
  • Compared to other models, the 2018 CRF150RB's air box design gives excellent access, making regular maintenance quicker and less messy.
  • If you ride in extremely wet conditions, inspect for moisture inside the air box as water intrusion can degrade filter performance.
  • Double-check the inner cage for cracks or missing gaskets, as the tight air seal is important for the CRF150RB's high-revving engine.
  • Log the dates, ride hours, and conditions of each clean or replacement to maintain a consistent maintenance regimen—proven to extend engine life.

When It–s Time to Replace

  • The dual-layer foam design for the CRF150RB is available in both OEM and reputable aftermarket options. Always check part compatibility by model/year.
  • Deteriorated or old filters can collapse or leak, severely increasing risk of engine damage due to dust or grit ingestion, especially under the high RPMs typical of the CRF150RB.
  • Replacing your air filter is a cost-effective way to maintain crisp throttle response and consistent power.

Routine air filter care is one of the simplest and most effective maintenance steps every 2018 Honda CRF150RB owner can perform. Make it part of every ride preparation for best results—your engine, and your lap times, will thank you.

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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.