Air Filter Cleaning – Replacement Guide for the 1973 Honda CR250

Shop parts for a 1973 Honda CR250 Dirt Bike.

The 1973 Honda CR250, known as the Elsinore, stands out as a highly collectible and race-inspired dirt bike from Honda's golden era. Taking care of its air filter is essential for maintaining peak two-stroke performance and protecting the engine from dirt and debris. This MotoSport.com guide covers proprietary steps for cleaning and replacing the air filter, highlighting tips specific to this classic model.

Why Air Filter Maintenance Matters for Your 1973 CR250

  • Engine life: Dirty or clogged air filters allow abrasive particles into the engine, causing accelerated wear.
  • Performance: Proper airflow is required for crisp throttle response typical of the '73 Elsinore.

Before You Start

  • Work in a clean, dust-free area.
  • Have gloves, a parts tray, and dedicated air filter oil on hand.
  • The 1973 CR250 typically uses a foam air filter element housed in the side panelcheck for original or aftermarket fitment compatibility.

Removal of the CR250 Air Filter

  1. Remove the side number plate or airbox cover by loosening the retaining screws or clips.
  2. Carefully take out the filter, noting the orientation and seal arrangement.
  3. Inspect the filter for tears, brittleness, and saturation with debris or old oil.
  4. Wipe down the inside of the airbox and ensure the intake tract is clear.

Cleaning the Filter

  1. If using a reusable foam filter (original or modern replacement), gently tap to remove loose debris.
  2. Submerge in a bucket of dedicated air filter cleaner or a mild soap solution. Never use gasoline or strong petroleum-based solvents as these degrade the foam structure.
  3. Squeeze (do not twist) the filter to expel dirt. Repeat until water runs clear.
  4. Rinse thoroughly with clean water and allow to air dry completely away from direct heat or sunlight.

Oiling & Reinstallation

  1. Apply air filter oil evenly to the foam once dry. Work the oil gently through the foam to ensure complete coverage without over-saturating.
  2. Wipe excess oil from the filter's sealing edges to prevent slippage or poor sealing in the airbox.
  3. Inspect the airbox-to-carburetor boot for cracksa common issue on vintage bikes.
  4. Reinstall the filter, checking for a secure and airtight fit. Replace the airbox cover/side plate and tighten the fasteners evenly.

Replacement and Model-Specific Tips

  • If the foam is crumbling, permanently stained, or torn, replace it with a new pre-oiled air filter specifically designed for the 1973 CR250. Modern pre-oiled filters simplify installation and ensure optimal protection.
  • OEM-style filters and airbox rubbers are still available. Inspect all mounting rubbers and clamps for aging – fresh parts improve reliability and preserve vintage value.
  • Regular cleaning after every few rides, or more often in dusty environments, can double the life of your two-stroke engine.

1973 Honda CR250 Owner Insights

  • This model's airbox is relatively easy to access but can be prone to water and mud infiltration – always check the airbox for residue after wet rides.
  • Retain any functional original parts; restoration-quality replacement filters and hardware can be found through reputable dealers.
  • When storing the bike, remove and dry the filter/airbox to prevent deterioration during periods of non-use.

Maintaining your 1973 Honda CR250's air filter is simple but critical for legendary Elsinore performance on track or trail. MotoSport.com provides the genuine and aftermarket parts you need for every step—and every ride.

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Shop Intake Parts for a 1973 Honda CR250 Dirt Bike.

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.