How to Change the Coolant in a 2012 GAS GAS TXT PRO 125
Keeping your GAS GAS TXT PRO 125 running at optimal performance means routine maintenance of its essential systems. Coolant replacement is a key part of care–especially for trials bikes that operate in challenging conditions. This step-by-step guide walks you through draining, flushing, and replacing the coolant in your 2012 TXT PRO 125.
Important Model Notes
- Alloy Cooling System: Only use coolant formulated for lightweight alloy motors to avoid internal corrosion and preserve cooling performance.
- 2-Stroke Engine: The 125 cc 2-stroke single needs an unobstructed, clean cooling system–especially under low-speed, high-output trials use.
- Servicing Access: For the best access to radiator and related components, remove the fuel tank by unscrewing the upper mounting bolt, sliding the tank upward, and disconnecting the fuel hose at the petcock. Work with a cool engine to prevent scalding.
Tools & Supplies You Need
- Correct type of coolant for alloy engines
- Drain pan
- Phillips and Allen wrenches
- Clean water (preferably distilled) for flushing
- Protective gloves & rags
Step-by-Step Coolant Change Procedure
- Ensure Engine Is Cold: Never open the radiator cap or drain coolant while hot, as pressurized steam can cause severe burns.
- Remove the Fuel Tank:
- Turn fuel valve off and disconnect the fuel line at the petcock.
- Unscrew the upper tank mounting bolt and carefully lift the tank off to reach the radiator fill cap and hoses.
- Drain Old Coolant:
- Locate the lowest point of the cooling system, typically a drain bolt on or near the water pump housing, or disconnect the lowest radiator hose.
- Position a drain pan underneath, remove the bolt/hose, and let coolant fully drain.
- Flush the System (Recommended):
- Reconnect the drain and fill the radiator with distilled water.
- Briefly run the engine (with radiator cap off), then shut off, drain again, and repeat if coolant was heavily contaminated.
- Refill with New Coolant:
- Install the drain bolt/hose securely.
- Slowly fill the radiator with the correct coolant until it reaches the base of the filler neck, allowing air bubbles to escape.
- Bleed Air from the System:
- With the radiator cap off, start the engine and let it idle. As the engine warms, trapped air may bubble out.
- Top off the coolant as needed during this process.
- Install the radiator cap before the coolant begins to overflow.
- Heat Cycle and Final Level Check:
- Run the engine up to operating temperature, let it cool completely, then check coolant level again.
- If needed, top up at the radiator and in any expansion tank.
- Reinstall the Fuel Tank:
- Place the tank back into position, reconnect the fuel line, and securely refasten the upper mounting bolt.
Tips for GAS GAS TXT PRO 125 Owners
- Check the coolant level often, especially after the first few heat cycles following a change. This prevents overheating from unnoticed air pockets.
- Avoid mixing coolants from different manufacturers, which can reduce corrosion protection and cooling efficiency.
- Inspect hoses and radiator for leaks or aging when you have the tank off.
The 2012 GAS GAS TXT PRO 125 is engineered for high agility and reliability in trials riding–maintaining the cooling system protects performance and longevity on demanding courses. For parts, upgrades or replacement components, MotoSport has everything you need to keep your bike ready for the next challenge.
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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.