How to Change the Coolant in a 2020 Honda CRF125F

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Regular coolant changes are essential for the longevity and performance of your 2020 Honda CRF125F. This MotoSport guide will walk you through the process step-by-step, highlighting any special notes unique to this specific year and model. Always consult your owner's manual for proper maintenance intervals and specifications before you begin service.

Tools & Supplies Needed

  • Fresh coolant (Honda-compatible pre-mix or as specified)
  • Socket set & hand tools
  • Drain pan
  • Funnel
  • Rags and gloves

Preparation & Safety

  • Make sure the engine is completely cool before starting. Opening the radiator cap when hot can cause serious burns.
  • Work in a well-ventilated area and properly dispose of used coolant according to local regulations.
  • Keep the motorcycle upright to ensure all coolant drains completely.

Step 1: Remove the Left Side Cover

On the 2020 CRF125F, you must remove the left side cover to access the radiator and cooling system:

  • Remove bolt A and bolt B, along with the collar. Keep track of these small parts.
  • Gently pull the prong out of the rubber grommet, then remove the boss from the shroud's corresponding hole.
  • Carefully maneuver the left side cover away and set it aside for reinstallation later.*

Step 2: Access the Radiator Cap

  • With the side cover off, locate the radiator cap on the left side of the frame. Remove it by turning it counterclockwise.
  • This step allows air into the system and helps coolant drain freely.

Step 3: Drain the Old Coolant

  • Place a drain pan below the water pump area (lower engine left side).
  • Locate the coolant drain bolt on the water pump housing (typically a 10mm bolt).
  • Remove the drain bolt and allow all coolant to drain from the system.
  • If equipped, remove the small cylinder head drain bolt as well for a more thorough flush.
  • Inspect and replace any sealing washers as needed to prevent leaks.

Step 4: Flush the Cooling System (Optional)

  • If the coolant was especially dirty or contaminated, pour distilled water through the radiator neck and let it drain out fully before installing the bolts.

Step 5: Reinstall Drain Bolts

  • Reinstall the drain bolt(s) and tighten securelydo not overtighten, as this could strip threads.

Step 6: Fill with New Coolant

  • Using a funnel, slowly pour fresh coolant into the radiator. Fill until the fluid reaches the bottom of the filler neck.
  • Move the handlebars side to side during filling. This helps any air bleeds escape from the cooling system.

Step 7: Bleed the System

  • Reinstall the radiator cap and start the engine. Let it idle for several minutes, then shut off and let it cool.
  • After the bike is cool, remove the cap and top off with coolant if necessary. Repeat this process until the coolant level remains steady.

Step 8: Reinstall the Side Cover

  • Slide the top of the cover under the seat edge. Align the prong with the grommet, the boss with its shroud hole, and reattach bolts and collar firmly.*

Step 9: Inspect & Test

  • Check for leaks around drain bolts and the radiator cap. Make sure the system is free of air bubbles and the coolant stays at the correct level.
  • Dispose of your old coolant responsibly.

Special Notes for 2020 CRF125F Owners

  • This model's radiator is relatively compact. Keeping it clean and free of mud buildup is especially important for optimal cooling in tight off-road situations.
  • Always use a coolant blend compatible with aluminum engines to avoid internal corrosion.
  • If you notice high engine temperatures or overheating, inspect coolant levels and radiator fins for blockages after each ride.
  • Do not run the bike without coolant; the engine relies on liquid cooling for all operating conditions.

Stay safe, ride with confidence, and rely on MotoSport for all your parts and maintenance supplies.

— MotoSport Service Team

* Based on 2021 CRF125F owner's manual, which covers the same procedure for side cover removal and installation.

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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.