How to Change the Oil in a 2021 Honda CRF450RW

Shop parts for a 2021 Honda CRF450RW Dirt Bike.

Tools and Supplies Needed

  • 8 mm socket
  • 10 mm Allen key (for drain plug)
  • Torque wrench (recommended for correct spec on reassembly)
  • Drain pan
  • Funnel
  • Measuring cup (for accurate oil fill)
  • Clean rags
  • Rubber gloves (optional for cleanliness)
  • Contact cleaner (optional, for cleaning up spills)
  • Replacement engine oil (Honda GN4 10W-30 or equivalent, per owner's manual)
  • New oil filter and O-rings (Honda OEM recommended)

Preparation Steps

  • Warm up the engine by starting the bike and letting it run for 1–3 minutes. This helps the oil thin out, ensuring it drains completely. Do not overheat—just let the motor idle and warm the cases.
  • Ensure the bike is safely supported and on level ground. A stand is recommended for stability.

Step-by-Step Instructions

  • Remove the Skid Plate
    Most 2021 CRF450RW models use a factory skid plate held by two 10 mm collared bolts. Remove these with your 10 mm socket; aftermarket or carbon skid plates may use a different fastener, so inspect what's on your bike and use the appropriate tool.
    Call-out: Don't lose the collars or hardware, and note aftermarket plates may require extra steps for removal.
  • Locate the Drain Plug
    The drain plug is located in the same position as on previous CRF450R/RX models (2017 and newer, as well as 450X/L models). It is accessible after the skid plate comes off, and it requires a 10 mm Allen wrench to remove.
    Call-out: Many owners overtighten this plug—if it is hard to loosen, apply steady force, but do not use excessive aggression to avoid stripping.
  • Drain the Oil
    Position your drain pan under the drain plug. With the bike warm, remove the drain plug using the 10 mm Allen. Be cautious, as hot oil may flow quickly. Allow all oil to drain— this may take several minutes. Inspect the old oil for metallic shavings or discoloration, which could indicate engine wear.
    Tip: If possible, tip the bike gently side-to-side to purge any residual oil.
  • Remove and Replace the Oil Filter
    Locate the oil filter cover on the side of the engine. Remove the cover bolts (8 mm socket typically required). Pull out the old oil filter, noting the direction for correct reinstall. Install the new oil filter in the same orientation. Replace O-rings with new ones from your oil change kit if available, lubricating them with fresh engine oil before fitting.
    Model-specific tip: Always verify the correct oil filter number in your owner's manual.
  • Reinstall the Drain Plug
    Clean the drain plug and inspect or replace the washer if damaged. Thread the plug in by hand to prevent cross-threading, then torque to factory specification. Do not overtighten—the plug is often aluminum and prone to damage.
    Call-out: Torque spec may vary; consult your owner's manual.
  • Add Fresh Oil
    Using the recommended oil and a funnel, pour in the specified quantity for the 2021 CRF450RW (typically just under 1 quart, but check your owner's manual for exact capacity). Add oil slowly to avoid spilling.
    Model-specific tip: Overfilling can result in oil blowing out the breather, while underfilling can harm the engine. Double-check level once filled.
  • Check for Leaks and Final Oil Level
    Reinstall skid plate and any covers. Start the bike and let it idle for 1 minute. Shut it off, wait a minute, then check the oil level per the manual's instructions. Top off if necessary. Wipe any spills or drips and recheck for leaks around the drain plug and oil filter cover.
    Call-out: Always perform a final check before your next ride.

Model-Specific Call-Outs for 2021 CRF450RW

  • The drain plug location and removal procedure are nearly identical to other 2017–2021 CRF450R/RX models, as well as the 450X and L/RL variants, using a 10 mm Allen.
  • Overtightening the aluminum drain plug is a common mistake; always use a torque wrench for reinstallation.
  • Change oil at least every 15 hours of use, or more often under race or hard riding conditions.
  • Honda recommends GN4 10W-30 oil or equivalent and genuine Honda oil filters for best engine life.
  • Check your owner's manual for exact oil capacity and torque specs, as aftermarket skid plates or modifications may affect some procedures.

MotoSport.com Pro Tip

For convenient and guaranteed fitment, order the Tusk four-stroke oil change kit or Honda-authorized oil change kit from MotoSport.com, which includes the exactly matched filter, O-rings, and factory-recommended oil in one package. Keep a log of your change intervals, and always use your own judgment if riding in especially dusty or high-heat conditions—early oil changes are cheap insurance for your high-performance engine.

Related Shopping Categories

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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.