Air Filter Cleaning & Replacement Guide for 1990 Suzuki DR650S

Shop parts for a 1990 Suzuki DR650S Dirt Bike.

The 1990 Suzuki DR650S features a foam primary air filter along with a secondary filter for crankcase ventilation. Routine maintenance of these filters is crucial, as dirt buildup will restrict airflow, reduce performance, and risk engine wear.

Required Tools & Materials

  • Phillips-head screwdriver
  • Disposable gloves
  • Kerosene or air filter cleaner solution
  • Two buckets
  • Warm water
  • Motorcycle-specific air filter oil (non-aerosol or spray type)
  • Grease for seal (optional)
  • Replacement filter (if needed)

Removing the Air Filter (1990 DR650S)

  • Remove the left side panel.
  • Unscrew and remove the air box cover.
  • Locate and undo the white retainer clip and the filter cage screw.
  • Extract the foam air filter element for inspection.
    Note: Inspect for cracks or tears–if found, replace the filter for proper sealing.

Cleaning the Main Foam Air Filter

  • Fill one bucket with about 600 ml of kerosene or a dedicated filter cleaner.
  • Submerge the foam filter in the cleaner, gently squeezing it to release dirt–never twist or wring as this may cause damage.
  • Rinse thoroughly in clean water and let it air dry completely (overnight recommended).
  • Wash the inside of the air box while the filter dries.

Oiling & Reinstalling the Main Filter

  • Apply air filter oil evenly–either spray while holding about three inches away or use the liquid type (pour, then massage for full coverage).
  • Let the filter sit for 20 minutes and inspect for missed spots–reapply oil as needed.
  • Lightly grease the air box seal surface (optional) to ensure a tight fit.
  • Reinstall the foam filter, cage, retainer clip, and replace all covers.

Maintaining the Secondary Filter

  • Locate the breather hose filter behind the starter motor. To inspect or clean, cut off about one inch of hose at the carburetor end (if replacing).
  • Check the filter for dirt or obstructions, wash with warm water as needed, and let dry completely before oiling and reinstalling.
  • Secure the new secondary filter with a zip-tie to the adjacent wiring harness, keeping it slightly recessed below the airbox top for optimal function.

Installation Tips Specific to the DR650S

  • The filter is held in place by a white clip and a JIS (Japanese Industry Standard) machine screw–ensure not to over-tighten to avoid damaging the housing.
  • If installing a new filter, make sure the cup side of the retainer clip faces up for easier fitment and to prevent filter deformation.
  • The stock filter often lasts many miles, but replace it if the foam appears old, brittle, or cracked. 

Things to Note About Your 1990 DR650S

  • Older units may still retain their original air filters. If unable to confirm the age or condition, err on the side of replacement for best reliability.
  • Any time you perform an oil change, check for an oil drain washer—the DR650S does not always come with one pre-installed.
  • Properly seated and oiled air filters provide the best piston, ring, and valve protection. Always double-check fit and cleanliness before reassembly. 

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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.