How to Change the Oil in a 2021 Kawasaki KLX140R F 21/18

Shop parts for a 2021 Kawasaki KLX140R F 21/18 Dirt Bike.

Changing the oil on your 2021 Kawasaki KLX140R F 21/18 is a straightforward but essential maintenance task that will keep your dirt bike running smoothly and extend its engine life. Follow this proprietary guide from MotoSport.com for a comprehensive, step-by-step oil change procedure.

Tools & Supplies Needed

  • 17mm wrench (for the drain plug)
  • 8mm socket and ratchet (for the oil filter cover bolts)
  • New oil filter – OEM recommended (Kawasaki part #52010-1053)
  • New drain plug washer (Kawasaki part #11061-0421)
  • 10W-40 4-stroke engine oil (1 quart, fully synthetic recommended)
  • Oil drain pan
  • Oil funnel
  • Clean shop rags
  • Brake cleaner (optional, for cleanup)
  • Torque wrench (optional, for precise bolt tightening)
  • Gloves (optional)

Preparation

  • Start the bike and let it warm up for 2–3 minutes. This helps the oil drain more completely by thinning it out.
  • Turn the engine off, place the bike on a level surface using a stand if available, and make sure it’s stable.

Step-By-Step Oil Change Instructions

  1. Drain the Old Oil
    • Place the oil drain pan under the engine’s drain plug.
    • Use the 17mm wrench to loosen and remove the drain bolt (located at the bottom of the engine).
    • Remove the old drain plug washer and let all the oil drain fully.
  2. Remove and Replace the Oil Filter
    • On the right side of the engine, locate the oil filter cover. It’s held in place with three 8mm bolts.
    • Use the 8mm socket and ratchet to remove these bolts, then gently take off the cover.
    • Remove the old oil filter. Check for the O-ring that sits under the cover—make sure it’s in good condition, clean, and properly seated. Replace it if damaged.
    • Install the new oil filter in the correct orientation (the open side of the filter faces outward).
    • Reinstall the oil filter cover and tighten the 8mm bolts to specification (do not overtighten).
  3. Install New Drain Plug Washer and Refit the Drain Plug
    • Fit a new drain plug washer to the bolt and reinstall it. Tighten securely (recommended torque: 22 Nm or 16 ft-lbs).
    • Wipe any oil residue from the area.
  4. Add Fresh Oil
    • Remove the oil fill cap on the right side of the engine.
    • Use an oil funnel to pour in one quart (946 ml) of 10W-40 motorcycle oil. This is the recommended amount for a full oil and filter change on a 2021 KLX140R F.
    • Reinstall the oil cap snugly.
  5. Final Checks
    • Start the engine and let it idle for one minute. Check for leaks around the drain plug and filter cover.
    • Turn off the bike and let it sit for several minutes to allow oil to settle.
    • Check the oil level using the dipstick. Add a small amount if needed to reach the correct level.
    • Wipe down and dispose of old oil and filter properly, according to local environmental laws.

Model-Specific Call-Outs for the 2021 Kawasaki KLX140R F 21/18

  • The KLX140R F uses a simple, externally accessible oil filter and drain plug—no need to remove the exhaust or skid plate for access.
  • Tighten all bolts to recommended torque using a torque wrench to avoid damaging threads, especially the drain bolt and oil filter cover bolts.
  • Always use a new crush washer on the drain bolt to help prevent leaks.
  • Oil capacity is 1 quart (946 ml) when changing the oil and filter together.
  • The correct oil specification is 10W-40, 4-stroke motorcycle oil.
  • After the change, always inspect for leaks around the oil filter cover and drain bolt before riding .
  • The KLX140 series (including the R/L/G/RF and relevant “F” models) share the same basic oil change procedure and part numbers for oil filters and washers between 2010 and 2021 models.

Pro Tips

  • Dispose of used oil and filter at a certified recycling center.
  • Record the date and hours for your next scheduled oil change. For most trail riders, change your oil every 10–15 hours of aggressive riding, or every three months.
  • If the old oil looks especially dirty or metallic, consider checking other engine components for wear.

Changing your oil regularly is the single best step you can take to ensure your 2021 Kawasaki KLX140R F delivers strong, reliable performance on the trail.

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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.