Air Filter Cleaning – Replacement Guide for 2018 Yamaha YZ85

Shop parts for a 2018 Yamaha YZ85 Dirt Bike.

The 2018 Yamaha YZ85 is engineered for aggressive performance and off-road reliability. Keeping its air filter serviced is crucial to maintain engine life, throttle response, and maximize your bike's power output. On the YZ85, the air filter is easily accessible, making regular cleaning or replacement straightforward for most riders.

Why Air Filter Maintenance Matters for Your YZ85

  • Engine Protection: A clean filter traps dirt & prevents debris from entering the engine, reducing the risk of costly damage.
  • Peak Performance: Airflow consistency is vital for crisp throttle response – a clogged filter suffocates horsepower.
  • Model Note: The YZ85's high-revving two-stroke engine is particularly sensitive to air restriction. Failing to service the filter will rapidly impact performance.

Proprietary MotoSport Air Filter Cleaning Procedure

  1. Preparation
    • Park the bike on a stable surface, ensure the engine is cool.
    • Gather gloves, socket wrench, recommended air filter cleaner, foam filter oil, and a clean bucket.
  2. Accessing the Air Filter
    • Remove the number plate bolts using a socket wrench.
    • Lift and remove the seat to expose the air box.
    • Locate the wingnut securing the filter cage – unscrew and gently slide the air filter away from the cage.
      (On the YZ85, take care not to drop debris into the air boot while removing the filter.)
  3. Inspection
    • Visually inspect the air filter for tears, excessive wear, or degraded foam.
      If damaged, discard – replace with an OEM or high-quality aftermarket filter.
    • Clean out any loose debris or dirt in the air box area with a clean, damp rag.
  4. Cleaning the Filter (if reusable)
    • Soak the foam filter in proprietary MotoSport air filter cleaner or a recommended product.
    • Gently massage the dirt out, do not twist or wring the foam to avoid tearing.
    • Rinse in clean, warm water, repeating as needed until no residue remains.
    • Allow the filter to air dry completely – do not use compressed air or direct heat.
  5. Oiling the Filter
    • Apply MotoSport foam filter oil thoroughly, ensuring full penetration.
    • Massage oil into all portions of the foam so no dry spots remain.
    • Avoid using aerosol spray oils – liquid oil coats more evenly and offers better protection.
    • Wipe away any excess oil.
  6. Reinstallation
    • Apply a thin layer of lithium soap-based grease on the filter's mounting flange for improved seal.
    • Insert the filter, reinstall the cage and wingnut, ensuring a snug fit with no gaps.
    • Replace the seat and secure the number plate.

2018 YZ85 Specific Considerations

  • The air box on the YZ85 is more exposed compared to larger models; always inspect for mud or debris intrusion after wet, dusty, or sandy rides.
  • Owners report easier filter access, but also note that careless removal can allow foreign material into the intake tract. Cover the air boot when servicing to prevent contamination.
  • Given the bike's racing pedigree, air filter checks should be performed every ride or after every few hours of aggressive riding.
  • The stock filter is foam – only clean with foam-approved solvents & oil.

Replacement Intervals

  • Replace the air filter if you notice tears or significant stiffness in the foam.
  • For racers or frequent riders, consider a spare filter to minimize downtime – swap filters when one is drying after cleaning.

Final Tips

  • Always use gloves when handling filter oil – it's sticky and hard to clean off skin.
  • Document your filter maintenance dates for optimal engine care.
  • Invest in quality foam oil – cheap substitutes risk engine life.

MotoSport supports your 2018 Yamaha YZ85 with all maintenance essentials – keep your ride at peak performance with regular air filter care.

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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.