How to Change the Coolant in a 2009 Yamaha TTR125

Shop parts for a 2009 Yamaha TTR125 Dirt Bike.

Changing the coolant on your 2009 Yamaha TTR125 is a key maintenance step to keep your engine running at the right temperature and protect its internals from corrosion and overheating. While the TTR125 is air-cooled and does not use conventional radiator coolant like liquid-cooled motorcycles, it relies on proper oil and the air-cooling system to keep temperatures in check. If you have a TTR125 LE or a model with a big bore kit or aftermarket upgrades that add a coolant system, or if you intended to ask about engine oil (which is often confused with coolant maintenance on this model), the steps below clarify what you should do.

Noteworthy for TTR125 Owners

  • The factory 2009 Yamaha TTR125 uses air-cooling only–there is no radiator or traditional coolant system from the factory. Check if your specific unit has been modified before sourcing parts or coolant.
  • Engine temperatures are managed by the cooling fins and proper oil levels. Excessive overheating often points to low oil, clogged fins, excessive mud buildup, or operating outside normal conditions.
  • If you are looking to service the engine's oil (commonly mistaken as coolant maintenance), follow the manufacturer intervals for oil changes and inspect for clogging or excessive dirt on the fins and around the cylinder head.

Step-By-Step: Maintenance for TTR125 Cooling System

  1. Inspect Cooling Fins: Make sure the cylinder and head fins are free of mud, grass, and debris. These fins are critical to heat dissipation in the Yamaha TTR125. Use a soft brush or compressed air to clean them.
  2. Check Engine Oil: Oil helps moderate engine temperature on air-cooled models. Warm up the bike, shut it off, and wait a minute. Remove the dipstick, wipe clean, reinsert without threading, then check the oil level. Top off as needed with the recommended oil.
  3. Change Engine Oil (if due):
    • Remove the oil drain bolt under the engine and allow oil to fully drain.
    • Replace the drain bolt and fill with fresh oil to the correct spec, referring to your owner's manual for the right volume and rating.
  4. Inspect for Aftermarket Radiator: If your TTR125 has been modified with a liquid cooling system, inspect the radiator or hoses for any leaks. If present, follow the standard coolant replacement steps:
    • Remove the radiator cap when the engine is cold.
    • Locate and loosen the drain bolt (often at the lowest point of the radiator or water pump).
    • Drain old coolant into a proper container.
    • Close the drain bolt, fill with manufacturer-recommended coolant, and "burp" the system by rocking the bike and running the engine briefly with the cap off to remove air pockets.
    • Top off as needed and replace the radiator cap securely.
  5. Dispose of Waste Properly: Used oil or coolant must be taken to a recycling center or auto parts store that accepts fluids. Never pour fluids on the ground or down a drain.

TTR125-Specific Tips

  • The TTR125 is exceptionally reliable with minimal upkeep needed, but regular oil changes and clean cooling fins are the key to engine longevity.
  • If you experience overheating, check for obstructed airflow, too slow riding in high ambient temps, or underfilled oil.
  • No need to purchase radiator coolant for the stock model–stick to top-tier motorcycle oil and air filter upkeep.

For all your maintenance parts, upgrades, and service intervals, trust MotoSport to keep your 2009 Yamaha TTR125 performing its best.

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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.