How to Change the Oil in a 2021 Honda CRF450RL: A Complete MotoSport.com Guide

Shop parts for a 2021 Honda CRF450RL Dirt Bike.

Changing the oil in your 2021 Honda CRF450RL is a crucial part of maintaining engine performance and longevity. This robust step-by-step guide provides all the tools, techniques, specific call-outs, and tips you need, specifically tailored for the CRF450RL model year.

Tools & Materials Needed

  • 10 mm socket or wrench (for skid plate bolts)
  • 10 mm Allen key (for drain plug)
  • 8 mm socket or wrench (for side engine cover bolts)
  • Ratchet and suitable extensions
  • Torque wrench (for reinstalling drain plug and cover bolts)
  • Oil drain pan
  • Funnel
  • Clean shop rags
  • Latex or nitrile gloves (optional, for less mess)
  • Contact cleaner (optional, for cleanup)
  • Measuring cup (for precise oil volume)
  • New oil filter (Honda OEM or equivalent)
  • New crush washer or O-ring for drain bolt (recommended)
  • Engine oil (10W-30 API SJ or higher, 1.2 quarts or 1.1 liters required)

Step-by-Step Process

  • Warm Up the Engine
    • Start your CRF450RL and let it idle for about 3 minutes. This ensures the oil is warmed up, which helps it drain more thoroughly and carries out more contaminants.
  • Remove the Skid Plate
    • Locate the skid plate; it’s typically attached with three 10 mm bolts (one on each side and one underneath the bike).
    • Remove all bolts with a 10 mm socket or wrench and set the skid plate aside.
  • Drain the Engine Oil
    • Find the oil drain plug underneath the engine (requires a 10 mm Allen key).
    • Position your oil catch pan directly under the drain bolt.
    • Slowly remove the drain plug, taking care not to drop it into the pan.
    • Allow oil to fully drain—this may take a few minutes. Tilting the bike side-to-side gently can help evacuate old oil.
  • Remove the Side Engine Cover and Filter
    • Locate and remove the left side engine cover using an 8 mm socket or wrench. This exposes the oil filter.
    • Carefully extract the used oil filter and note its orientation for proper installation of the new filter.
  • Inspect and Clean
    • Check the condition of the used oil and filter for unusual debris—excessive metallic particles can indicate abnormal engine wear.
    • Inspect and, if necessary, replace the drain plug crush washer or O-ring to prevent future oil leaks.
    • Wipe down the drain plug, filter housing, and surrounding area using clean rags and optional contact cleaner.
  • Install the New Filter
    • Lubricate the rubber seal of your new oil filter with a drop of fresh oil.
    • Insert the filter into the housing, matching the orientation of the filter noted during removal.
  • Reinstall Side Engine Cover
    • Secure the cover with the original 8 mm bolts—use a torque wrench set to factory torque spec (consult owner’s manual).
  • Reinstall Drain Plug
    • Thread the drain plug (with new crush washer/O-ring) by hand to avoid cross-threading, then tighten with the 10 mm Allen key.
    • Use the torque wrench to tighten to Honda’s specification (typically around 18 lb-ft, but always confirm with the manual for the exact spec for your model year).
  • Refill With Fresh Oil
    • With the bike upright and level (off the stand), pour in 1.2 quarts (1.1 liters) of 10W-30, API SJ or higher engine oil using a funnel.
    • Wait a few seconds for the oil to drain down and then check the oil level with the dipstick without threading it in. Add more oil if needed, but do not overfill.
  • Reinstall Skid Plate
    • Replace the skid plate and secure it with its three original bolts.
  • Start the Engine and Check for Leaks
    • Start the bike and let it idle for approximately one minute, then switch it off and check for oil leaks at the drain plug, filter, and cover.
    • Allow a minute for the oil to settle, then recheck the oil level and adjust if necessary.

2021 CRF450RL Model-Specific Tips & Call-Outs

  • Honda recommends oil changes every 600 miles, but owners often safely stretch intervals to 1,000–1,200 miles if using high-quality oil and filter and the bike isn’t raced hard. Always follow Honda’s conservative schedule for optimal engine life.
  • The drain plug can be very tight: Use a quality Allen key and maintain positive pressure to avoid stripping the plug. Replace the plug or washer as needed.
  • Oil capacity is 1.2 quarts (1.1 liters)—do not exceed this amount as overfilling can cause excessive crankcase pressure or leaks.
  • Use only 10W-30 API SJ or higher engine oil. Lower spec oils or incorrect viscosity lead to premature wear or clutch issues.
  • Always torque bolts to factory specification using a torque wrench to avoid stripping engine casings or oil leaks.
  • Check for oil leaks after first ride and inspect the oil level once more; topping off as needed will ensure the bike’s longevity and peak performance.

Final Thoughts

Routine oil changes are the single most important maintenance task to preserve the life and performance of your CRF450RL. If you ever have questions or trouble, consult your Honda factory service manual or reach out to MotoSport.com professionals for help with parts and expert guidance.

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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.