How to Change the Coolant in a 2016 Honda CRF125FB

Shop parts for a 2016 Honda CRF125FB Dirt Bike.

Changing the coolant in your 2016 Honda CRF125FB is a fundamental part of routine maintenance, preserving your engine life and ensuring optimal performance on and off the track. As a lightweight trail bike, the CRF125FB is built for reliability, but regular coolant changes protect your cylinder head and water pump, especially during hard riding or warm conditions. Here is a step-by-step guide, made just for MotoSport customers, to get your bike ready for more miles ahead.

Tools & Supplies Needed

  • Silicate-free motorcycle coolant (premixed, or mix as instructed by the bottle)
  • Phillips screwdriver
  • 8mm & 10mm sockets with ratchet
  • Drain pan
  • Rubber gloves & eye protection
  • Rags or paper towels
  • New sealing washer for the drain bolt (recommended)
  • Optional: distilled water if flushing system

Preparation & Safety

  • Ensure the engine is completely cool before beginning to avoid scalding injuries.
  • Place the bike upright on a stand for stability.
  • Work in a well-ventilated area and use gloves since coolant can irritate skin.

Removing Plastics & Getting Access

  • Remove side panels or shrouds as needed to access the radiator cap and radiator. Most require only basic hand tools and a few screws.
  • Locate the radiator cap on the left side of the bike. If your model has a radiator guard, remove it as needed.

Draining the Old Coolant

  • Place a drain pan beneath the water pump's drain bolt at the lowest point of the cooling system (typically on the right side of the engine).
  • Protect paint from spills–coolant can stain.
  • Slowly open the radiator cap to relieve any pressure. Always do this with a rag over the top, and release any hissing pressure before fully removing the cap.
  • Remove the drain bolt and let the coolant drain completely.
  • If equipped with a reservoir bottle, drain it by disconnecting the hose or temporarily removing the tank. Some models allow you to tip the bike slightly to encourage complete drainage.

Optional: Flushing the System

  • For neglected cooling systems, flush with a 50/50 mix of distilled water and vinegar. Reassemble the system, fill, run the bike until warm, then drain. Repeat flush with distilled water only, then drain.

Refilling with Fresh Coolant

  • Install a new sealing washer on the drain bolt and tighten it securely.
  • Fill the radiator slowly with fresh, silicate-free coolant, using a funnel to avoid spills.
  • Gently squeeze radiator hoses to work out any air bubbles as you fill. Fill until coolant is visible at the neck.
  • If your CRF125FB has an overflow reservoir, fill it to the upper line.

Bleeding Air from the System

  • Leave the radiator cap off.
  • Start the engine and let it idle for a few minutes–watch for the coolant level to drop as air escapes.
  • Rev the engine gently a few times and add coolant as needed until the level stabilizes.
  • Turn off the engine, allow it to cool, and top off again if necessary.
  • Install the radiator cap securely and reinstall any plastic covers or panels.

Cleanup & Disposal

  • Wipe up any spills immediately, as antifreeze is toxic to pets and wildlife.
  • Dispose of used coolant at a recycling center–never pour it down the drain or onto the ground.

Model-Specific Notes for the 2016 CRF125FB

  • This model uses a simple, air-assisted single radiator system with minimal plastic removal, making coolant changes quick compared to race bikes.
  • Always use silicate-free coolant to prevent corrosion of the aluminum components.
  • The cooling capacity is modest–avoid overfilling. Reference your owner's manual for exact coolant volume.
  • Check hose clamps and connections for leaks after your first post-service ride.
  • 2016 CRF125FB radiators are vulnerable to damage from tip-overs–inspect for bent fins or leaks while performing this service.

Changing your coolant every two years or sooner if you ride in severe conditions keeps your Honda CRF125FB performing at its best, whether you are hitting the trails for weekend fun or pushing through a long race day.

Related Shopping Categories

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Shop Radiator Hoses for a 2016 Honda CRF125FB Dirt Bike.

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.