How to Change the Coolant in a 2011 Yamaha TTR125L

Shop parts for a 2011 Yamaha TTR125L Dirt Bike.

Proper coolant maintenance is essential for the longevity and reliable performance of your 2011 Yamaha TTR125L. Unlike many air-cooled smaller dirt bikes, the TTR125L's engine relies on effective engine heat management, and a regular coolant flush will help prevent overheating, corrosion, and early component wear. Below is a proprietary guide from MotoSport on how to change the coolant in your TTR125L, including tips and model-specific considerations.

What You Will Need

  • Fresh, motorcycle-specific coolant (avoid automotive coolant, since additives may be unsuitable for your bike)
  • Drain pan
  • Socket wrench with 10mm socket
  • Flathead screwdriver
  • Rags for cleanup
  • Funnel
  • Distilled water if a flush is needed
  • Screwdriver or wrench for plastic panels if removal is necessary

Before You Start

  • Make sure the engine is completely cool before beginning the coolant change.
  • Prepare your work area with plenty of ventilation and keep coolant away from children & pets, as it is toxic.
  • If your TTR125L has been ridden in especially muddy or dusty conditions, consider removing the side panels for better access to the radiator and overflow reservoir.

Step-by-Step Guide

  1. Locate the Radiator Cap. On your TTR125L, the radiator cap is typically found on the left side behind the shroud. Remove the shroud or side panel if necessary using the appropriate tool.
  2. Remove the Radiator Cap. Loosen the cap slowly to relieve any residual pressure – do this carefully to avoid burns from hot steam if the engine is not completely cool.
  3. Position the Drain Pan. Place a drain pan directly under the water pump area in line with the engine’s lower hose or at the lowest point on the engine block.
  4. Remove the Drain Bolt. Use a 10mm socket to remove the coolant drain bolt, usually located at the bottom of the water pump cover. Let the coolant drain completely.
  5. Optional: Flush the System. If you haven’t changed your coolant in several years or the old coolant appeared rusty or milky, flush the system by filling with distilled water, running the engine briefly, and draining again.
  6. Check the Overflow Reservoir. On some TTR125L models, there is a small overflow tank hidden behind a panel. Remove the side panel and disconnect the reservoir. Drain it and clean if needed.
  7. Reinstall the Drain Bolt. Once everything is drained, reinstall and torque the drain bolt. Do not overtighten, as this can strip the threads.
  8. Fill with Fresh Coolant. Slowly pour new coolant into the radiator filler neck using a funnel. Fill to just below the filler neck.
  9. Bleed the System. To remove air pockets, gently rock the bike side to side and slowly squeeze the radiator hoses by hand. Reinstall the radiator cap.
  10. Fill the Overflow Reservoir (if equipped). Fill to the “Full” mark.
  11. Start and Run the Engine. Let the bike idle with the radiator cap installed to circulate coolant. Watch the temperature and check for leaks. Let the engine cool, then recheck and top off coolant in both the radiator and reservoir.

Tips for TTR125L Owners

  • The TTR125L has a robust air-cooled design but relies on efficient engine cooling – neglecting coolant maintenance leads to faster engine wear.
  • Always use coolants specified for off-road motorcycles; incorrect coolant types can damage seals and internal passages.
  • Inspect hoses and clamps for cracks or leaks every time you change your coolant. Replace weak components immediately.
  • Dispose of old coolant responsibly – do not pour it down the drain or onto the ground.

Wrap-Up

Coolant changes on the TTR125L are straightforward and can be performed with basic tools. Regular maintenance every two years or 24 engine hours (whichever comes first) will keep your bike running cool on every ride. For OEM and high-quality replacement parts, trust MotoSport to keep your Yamaha in peak condition.

Related Shopping Categories

Shop Radiators for a 2011 Yamaha TTR125L Dirt Bike.

Shop Coolant for a 2011 Yamaha TTR125L Dirt Bike.

Shop Temperature Sensors for a 2011 Yamaha TTR125L Dirt Bike.

Shop Tools for a 2011 Yamaha TTR125L Dirt Bike.

Shop Radiator Hoses for a 2011 Yamaha TTR125L 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.