How to Change the Coolant in a 2026 Honda CRF150R Big Wheel

Shop parts for a 2026 Honda CRF150R Big Wheel Dirt Bike.

Routine coolant changes are essential for the performance and longevity of your 2026 Honda CRF150R Big Wheel. Whether you race or ride for fun, keeping your cooling system in peak condition prevents overheating and avoids costly repairs. Here is MotoSport's step-by-step guide, along with key considerations specific to your CRF150RB.

What You'll Need

  • OEM-approved coolant (such as Pro Honda HP Coolant or another compatible high-performance motorcycle coolant)
  • Distilled water (for flushing, if needed)
  • Metric socket or wrench set (typically 8mm for the drain bolt)
  • Drain pan
  • Clean rags
  • Protective gloves
  • Funnel

Before You Begin

  • Ensure the engine is cool to prevent burns.
  • Work in a well-ventilated area.
  • This model's cooling capacity is approximately 0.76 liters (0.80 US qt); do not overfill.

Step-by-Step Coolant Change Process

  1. Remove the Radiator Cap: Locate the radiator cap on the left side of your CRF150RB. Open it to relieve internal pressure and allow smooth draining.
  2. Locate and Remove the Drain Bolt:
    • Find the water pump at the lower part of the right engine case.
    • The coolant drain bolt is the lower-most bolt with a copper washer.
    • Place a drain pan under the bolt, remove it, and let the coolant flow out completely.
  3. Drain the Old Coolant:
    • Allow gravity to empty the system. Tilting the bike gently from side to side can help evacuate remaining fluid.
  4. Flush the System (Recommended):
    • If the coolant appeared dirty, pour distilled water into the radiator, reinstall the drain bolt, and briefly run the engine, then repeat the drain process until clear water emerges.
  5. Reinstall the Drain Bolt:
    • Check the copper washer for good condition to prevent leaks; replace if necessary.
    • Torque the bolt to the manufacturer's spec – do not overtighten.
  6. Add Fresh Coolant:
    • Using a funnel, pour fresh coolant slowly into the radiator until it reaches the lower lip of the filler neck.
  7. Burp the System:
    • To release trapped air, gently rock the bike or squeeze the radiator hoses. You can briefly start the engine with the cap off, allowing bubbles to escape.
  8. Check and Top Off:
    • Add coolant if the level drops after "burping". Replace and secure the radiator cap.
  9. Dispose of Old Coolant Responsibly:
    • Coolant is toxic to pets & wildlife. Always take used fluid to a local recycling center.

Notes for the 2026 CRF150R Big Wheel Owner

  • The CRF150RB features a compact, high-output engine that's sensitive to overheating. Even small coolant losses can impact performance – inspect for leaks regularly.
  • For racing applications, ensure your coolant is both effective and race-legal; some tracks ban glycol-based coolants, so confirm local regulations if you compete.
  • Check your radiator guard and fins for mud or damage whenever you service coolant — clean and straighten as needed to optimize airflow.
  • Always double-check fluid levels after your first ride post-service. Air trapped during filling may work free, requiring a top-off.

Maintenance Tip

  • Your 2026 CRF150R Big Wheel is designed for high-performance off-road use. Observe Honda's maintenance intervals but consider more frequent coolant changes in harsh conditions or extended racing to maximize engine reliability.

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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.