How to Change the Oil in a 2021 Honda CRF450X: A Complete MotoSport.com Guide

Shop parts for a 2021 Honda CRF450X Dirt Bike.

Keeping your Honda CRF450X engine running at peak performance means regular oil changes. This guide will walk you through the entire oil change process, highlighting tools required, step-by-step instructions, and specific call-outs for the 2021 model. Following these directions ensures longevity and reliability on the track or trail.

Tools and Supplies Needed

  • 8mm and 10mm sockets
  • Ratchet
  • 10mm Allen key
  • Torque wrench
  • Drain pan
  • Rags
  • Rubber gloves
  • Contact cleaner (optional, for cleanup)
  • Funnel
  • Measuring cup (for precise oil amount)
  • New Honda oil filter
  • Honda 20W-50 4-stroke engine oil
  • Replacement crush washer
  • Replacement O-rings (inspect and replace if worn)

Recommended Oil Change Interval for the 2021 CRF450X

  • Honda recommends changing the oil and filter every 15 hours of use or after every 6 races, whichever comes first.

Step-by-Step Oil Change for the 2021 Honda CRF450X

  1. Warm Up the Engine
    • Start and let your CRF450X idle for 1 to 2 minutes. This warms the oil, allowing it to drain more thoroughly.
    • Turn off the engine and allow a minute for the oil to settle in the pan.
  2. Prepare the Bike
    • Place the bike on a level surface using a stand.
    • Remove the left side engine guard using an 8mm socket to access the oil filter cover.
  3. Remove the Oil Filler Cap
    • Unscrew the oil filler cap on the crankcase. This lets air in for a smoother, faster drain.
  4. Drain Old Oil
    • Position the drain pan below the engine–s drain bolt (located at the lower rear of the crankcase).
    • Using your 10mm socket or Allen key (depending on bolt style), remove the oil drain bolt and its crush washer.
    • Let the oil drain completely (several minutes, more if the oil is cold).
  5. Remove and Inspect the Oil Filter
    • Take off the oil filter cover (typically held with two 8mm bolts). Set aside carefully.
    • Remove the old oil filter. Inspect the rubber O-ring for wear – replace if needed.
    • Tip: On Honda thumpers, ensure the oil filter–s rubber ring faces toward the engine. There may also be a small spring behind the filter; make sure it–s not lost or misplaced.
  6. Install New Oil Filter
    • Lightly oil the rubber seal of the new filter.
    • Insert it into place, double-checking for orientation and spring placement.
    • Replace oil filter cover, tightening the two bolts to 9 foot-pounds with a torque wrench.
  7. Reinstall Drain Plug
    • Replace the old crush washer with a new one.
    • Install and torque the oil drain bolt securely (refer to your service manual for the exact torque value).
  8. Refill Engine Oil
    • Using a funnel, add Honda 20W-50 4-stroke oil to the fill port. Refer to your owner–s manual for the exact oil capacity, but expect around 1 quart (referencing the CRF450R, which is very similar)
    • Replace the filler cap.
  9. Check Oil Level
    • With the bike upright, check the oil level through the sight glass below the filler cap. If it–s below the center, add more oil as needed.
    • Be careful not to overfill.
  10. Inspect for Leaks and Test Run
    • Start the bike and let it idle for a few minutes. Watch for leaks at the oil filter and drain plug.
    • Shut off and let the oil settle for a couple minutes. Re-check the oil level in the sight glass and top off if necessary.
  11. Reinstall Left Side Engine Guard
    • After verifying no leaks, reinstall the guard using your 8mm socket.

2021 Honda CRF450X-Specific Callouts and Tips

  • Use genuine Honda parts: Aftermarket oil filters and O-rings may fit but can leak or compromise engine health.
  • Torque is crucial: Do not overtighten the oil filter or drain bolts. Use a torque wrench as instructed in your shop manual.
  • Oil window (sight glass): Unlike dipstick models, the CRF450X uses a sight glass for checking oil level – make sure the bike is upright and level.
  • Dispose of oil properly: Always recycle your used oil and filters in accordance with local regulations.
  • Inspect related components: Take the opportunity to check the skid plate, shift lever, and clutch cable for wear or looseness while doing your oil change.

Final Advice

  • Never ignore an oil change — engine damage and costly repairs will follow.
  • Keep track of your oil changes in a maintenance log for peace of mind and improving resale value.
  • Refer to your owner–s manual for interval recommendations, specs, and diagrams unique to your model and year.

Related Shopping Categories

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Shop Oil Fillers and Drain Plugs for a 2021 Honda CRF450X 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.