How to Change the Coolant in a 2008 Yamaha TTR125

Shop parts for a 2008 Yamaha TTR125 Dirt Bike.

If you want your 2008 Yamaha TTR125 to run cool and perform at its best, changing the coolant should be part of your regular maintenance routine. Unlike many motocross bikes, the TTR125 uses a simple, air-cooled enginemeaning it does not use liquid engine coolant like a water-cooled motocross bike. Instead of topping off a radiator, your priority is to check and change the engine oil regularly, keep the cooling fins on the cylinder free from dirt, and make sure the bike is not running overly lean or with a clogged air filter.

However, if you have a modified version, a pit bike kit with a supplemental oil cooler, or are referencing the overflow for a carburetor or other fluids, here is a general guide for fluid change on a TTR125:

  • Locate the appropriate drain bolt: For engine oil, the drain bolt will be on the underside of the engine case. For any external oil cooler kit (if equipped), there may be a separate drain plug.
  • Remove any skid plates or guards: Accessing the drain plug is easier without interference.
  • Drain the oil/fluids completely: Place an oil catch pan under the plug and let all fluid drain. For additional coolers, disconnect the lines to let any trapped fluid escape.
  • Clean and replace the crush washer (if present) before re-installing the drain bolt and torque it to factory specification.
  • Fill with fresh oil: Use the manufacturer-recommended oil type and volume. For a TTR125, use high-quality 10w-40 motorcycle oil.
  • Start the engine and let it idle for a few minutes to circulate the oil. Shut it off and check the oil level again once it has settled.
  • Inspect for leaks: After warming and rechecking levels, ensure there is no leaking fluid.

If you are searching specifically for a coolant flush or radiator service, it is important to know that the stock Yamaha TTR125 is air-cooledthere are no radiators, coolant hoses, or reservoirs to service. If your TTR125 is running hot or showing signs of overheating, focus on:

  • Cleaning dirt from the cylinder and head cooling fins
  • Verifying proper carburetor tuning and air filter cleanliness
  • Maintaining correct oil levels and performing timely oil changes

Pro tip for TTR125 owners: The simplicity and reliability of an air-cooled engine are perfect for beginners, making the TTR125 easy to own and maintain. Always use the correct oil and clean those cooling fins regularly. For any aftermarket parts, maintenance kits, or OEM replacements, MotoSport offers everything you need to keep your ride ready for the next adventure.

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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.