How to Change the Coolant in a 2007 Yamaha TTR125L

Shop parts for a 2007 Yamaha TTR125L Dirt Bike.

Regular maintenance is essential for top performance on your Yamaha TTR125L, and changing your coolant is a key part of that. Coolant protects your engine from overheating, freezing, and corrosion–so a fresh fill ensures your bike runs smoothly season after season. Below is a step-by-step guide tailored specifically for TTR125L owners.

What You Will Need

  • Fresh coolant (check your manual for type)
  • Distilled water (if flushing system)
  • Drain pan
  • Socket set (10 mm common)
  • Rags & gloves
  • Funnel
  • Replacement sealing washer (recommended)

Step-by-Step Coolant Change Process

  1. Let the engine cool completely. Never remove the radiator cap while the engine is hot due to risk of serious burns.
  2. Remove the radiator cap. Loosen the cap on your coolant reservoir or radiator. This releases pressure and lets air in as the old coolant drains out.
  3. Locate and remove the drain bolt. The drain bolt on the TTR125L is typically at the lowest point on the engine side cover or water pump cover. Position your drain pan underneath, then unscrew the bolt and let the coolant flow out completely.
  4. Inspect and clean. Check the condition of your drain bolt and sealing washer. Replace the washer if it looks worn. Take a moment to inspect for debris or corrosion in the drained coolant.
  5. Flush the system (optional, but recommended). For a neglected or unknown coolant system, use a 50/50 mix of distilled water and coolant, or just distilled water, to flush out old contaminants. Fill the radiator, run the engine several minutes, shut off, let cool, then drain again.
  6. Reinstall the drain bolt with a fresh washer. Hand-tighten and then snug with your socket–do not overtighten.
  7. Add new coolant. Use a funnel to slowly fill the radiator until coolant is visible at the filler neck. Fill the coolant reservoir to the "full" mark if equipped.
  8. "Burp" the system to remove air. Start the engine and let it idle, with the radiator cap off (if safe). Cycle the throttle and carefully rock the bike side to side to work out any air bubbles. Top off coolant if the level drops.
  9. Secure everything and check for leaks. Replace the radiator cap, reinstall any covers or panels you removed, and inspect for leaks around the drain bolt and hoses.
  10. Take a short test ride, then recheck levels. Once the engine returns to ambient temperature, check your coolant level again and top off if needed.

TTR125L Owner Tips – Model Notes

  • The TTR125L is air-cooled, meaning it does not use liquid coolant with a traditional radiator. If you have the standard TTR125L model, coolant changes are not required. However, always check your manual–if your bike is a modified variant with an aftermarket liquid cooling kit, follow the instructions above.
  • Always maintain good airflow across the cylinder fins to avoid overheating on this air-cooled bike.
  • Keep an eye on oil level and service intervals, as oil also plays a role in temperature regulation.

Maintaining your TTR125L is straightforward and crucial for years of fun. For all your OEM and aftermarket parts, MotoSport stocks the essentials to keep your Yamaha at 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.