How to Change the Oil in a 2021 Honda CRF150R

Shop parts for a 2021 Honda CRF150R Dirt Bike.

Changing the oil in your 2021 Honda CRF150R is crucial for performance and longevity. This guide is proprietary to MotoSport.com and will help you perform this maintenance task like a pro by detailing the required tools, step-by-step instructions, and specific model call-outs.

Tools and Materials You’ll Need

  • Honda GN4 4-stroke oil or a high-quality equivalent (about 600ml with filter replacement, 550-560ml without filter)
  • New oil filter (HI-FLOW HF116 is a popular aftermarket option if you want a cost-effective alternative)
  • O-ring for filter cover (replace if pinched or worn)
  • Ratchet and sockets (8mm and 12mm sockets required for drain bolts)
  • Flathead screwdriver (for O-ring replacement if needed)
  • Oil drain pan
  • Clean rag
  • Funnel
  • Gloves (to protect your hands from hot oil and grime)

Preparation Steps

  • Ensure the bike is on a stable, level surface, ideally using a stand.
  • Warm up the engine for a few minutes to let the oil flow out easily, but don’t let it get hot.
  • Turn off the engine and let it cool for a minute so you can safely handle bolts and parts.

Step-by-Step Oil Change Guide

  1. Remove the Oil Drain Bolt
    • Locate the engine oil drain bolt under the engine (be careful not to confuse it with the nearby transmission drain bolt).
    • Place your oil drain pan directly underneath the bolt.
    • Using a 12mm socket, loosen and remove the bolt. Let all old oil drain out completely.
  2. Remove and Replace Oil Filter (Every Other Oil Change)
    • The oil filter is on the right side of the engine behind a small cover held by bolts.
    • Remove the bolts and cover.
    • Pull out the old filter and check the O-ring. If the O-ring is pinched or damaged, replace it to avoid leaks.
    • Install the new filter, ensuring the O-ring seats properly.
    • Reinstall the cover and bolts, tightening them evenly.
  3. Replace the Drain Bolt
    • After oil has drained, wipe the area clean and reinstall the drain bolt. Be careful not to overtighten, as the threads can strip easily.
  4. Add New Engine Oil
    • Remove the fill cap/dipstick on top of the engine.
    • Using a funnel, pour in about 590-600ml if the filter was replaced. If you did not replace the filter, use 550-560ml.
    • Pour slowly to avoid spills and allow air to escape.
  5. Check Oil Level
    • Insert the dipstick, but do not screw it in. Wipe, reinsert, and check the oil level.
    • If necessary, add oil until you reach the correct level.
  6. Start and Inspect
    • Start the engine and let it idle for a minute, then shut it off.
    • Check for leaks, paying close attention to the oil filter cover and drain bolt.
    • Recheck oil level, top off if needed.

2021 CRF150R Model-Specific Call-outs

  • Dual oil systems: The CRF150R uses separate oils for the engine and transmission—make sure you are servicing the engine side for oil changes and not confusing the drain/fill locations. The transmission oil needs regular changes as well, but this is a separate process.
  • Oil and filter change intervals: Honda recommends changing the engine oil and filter every 15 hours or 6 races, whichever comes first. More frequent changes (every 6 hours for oil, and every 12 hours for the filter) are common among riders for optimal protection, especially under heavy or racing use. Always follow your manual and adjust intervals based on riding style and conditions.
  • Be careful with O-ring installation: Ensure the oil filter O-ring is seated properly every time. An improperly seated or pinched O-ring will cause leaks and possible engine damage.
  • Thread caution: The aluminum cases are soft—overtightening the drain bolt is a common mistake. Only tighten to the manufacturer’s specified torque.
  • Recommended oil specs: Use only high-quality 4-stroke motorcycle oil, such as Honda GN4, or equivalent, rated for wet clutches. Do not use automotive oil.

Additional Tips

  • Dispose of used oil and filters responsibly at a certified recycling center.
  • Keep a log of oil changes to maintain your bike’s reliability and value.
  • If you ride in extremely dirty, wet, or high-rpm conditions, consider shortening the interval.
  • Always check the manual or a certified dealer if unsure—every MotoSport.com customer deserves precise, professional guidance.

Oil changes are one of the best DIY maintenance tasks for keeping your CRF150R running strong—ride safe, ride prepared, and trust MotoSport.com for your dirt bike maintenance needs.

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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.