How to Change the Coolant in a 2013 Yamaha TTR125L

Shop parts for a 2013 Yamaha TTR125L Dirt Bike.

Regular coolant changes are essential maintenance for your 2013 Yamaha TTR125L, ensuring consistent engine cooling performance and long-term reliability. While the TTR125L uses a simple, air-cooled engine without a traditional liquid-cooling radiator like larger bikes, some variants may be fitted with an aftermarket oil cooling system or other auxiliary cooling systems that use a coolant solution. Confirm your specific model’s cooling setup before proceeding—if your TTR125L is stock and air-cooled, changing traditional motorcycle coolant is not required. If equipped with a liquid cooling system (rare on TTR125L but possible with modifications), follow this guide.

What You Need

  • Fresh, manufacturer-recommended coolant or coolant mix
  • Distilled water (if required for mixing)
  • Phillips or flat screwdriver and basic socket set
  • Drain pan
  • Rags and gloves for cleanup

Draining the Old Coolant

  • Ensure the bike is completely cool before starting–hot coolant can cause serious burns.
  • Locate the coolant reservoir and radiator cap, usually beneath a side panel or above the engine. On modified TTR125Ls with an aftermarket system, check the kit instructions for the fill location.
  • Remove the radiator cap to allow draining. Place the drain pan beneath the coolant drain bolt, usually at the water pump’s lowest point or at the base of the radiator, if equipped.
  • Remove the drain bolt and allow all coolant to fully drain. You may need to rock the bike gently to encourage complete drainage.
  • Inspect the coolant for any debris, rust, or oil, which may indicate other engine issues.

Flushing the System (If Needed)

  • For extremely dirty systems, flush with distilled water by replacing the drain plug, filling with distilled water, running the engine briefly, then draining again. Do not use tap water, as it can cause mineral deposits in the cooling system.
  • Repeat until the drained water runs clear.

Refilling with New Coolant

  • Replace the drain bolt and secure it tightly.
  • If using a coolant concentrate, prepare a 50/50 mix with distilled water unless otherwise specified by the coolant manufacturer.
  • Fill the radiator or coolant reservoir to the indicated level, pausing periodically to let air escape. Do not overfill.
  • Replace and tighten the radiator cap.

Burping the System & Checking Levels

  • Start the engine and let it idle with the radiator cap off for several minutes (if possible with your cooling setup) to allow any trapped air to escape. Watch for bubbling and top off coolant as the air is released.
  • Once the system is burped, reinstall the radiator cap.
  • Allow the engine to heat to normal operating temperature, then fully cool again. Re-check the coolant level and top off if needed–coolant will expand and contract as the system cycles.

Final Steps & Notes for TTR125L Owners

  • Reinstall any panels or guards you removed during the process.
  • Proper disposal of old coolant is critical–take it to a recycling center or auto parts store. Do not pour coolant down drains or onto the ground.
  • The TTR125L, in its stock form, is air-cooled and typically does not need coolant changes. These steps apply only to non-standard, liquid-cooled setup often found on highly modified versions. If your bike is air-cooled, focus on cleaning cooling fins and maintaining oil level for optimum thermal control.
  • Always refer to your owner’s manual or consult MotoSport’s extensive parts and advice database for specifics on your exact build and parts compatibility.

Stay on top of this simple maintenance and your TTR125L will run cool and strong for seasons of fun on the trail.

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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.