How to Change the Coolant in a 2011 GAS GAS TXT PRO 125
Maintaining the cooling system on your 2011 GAS GAS TXT PRO 125 is crucial for preserving engine healthespecially on a competition-oriented trials bike where performance and reliability are paramount. Follow this MotoSport-exclusive step-by-step guide for a complete coolant service, tailored to the specifics of the TXT PRO 125.
What Makes the 2011 GAS GAS TXT PRO 125 Cooling System Unique?
- Low coolant volume–the bike's compact radiator means less margin for error during refilling and air-bleeding.
- Cramped access–the trials frame places the radiators and coolant hoses in tight quarters, so patience and careful work are essential.
- 2011+ engine architecture–a wider frame and revised kickstart mechanism require attention to detail if you're working near other engine covers. Always confirm compatibility when ordering gaskets or covers related to the cooling system.
What You Will Need
- Fresh motorcycle-specific coolant (ethylene glycol-based, silicate-free, rated for aluminum systems)
- Drain pan
- Socket and wrench set
- Flathead and Phillips screwdrivers
- Funnel and clean rags
- Optional: distilled water (if flushing is necessary)
- Safety gloves and glasses
Step-By-Step Coolant Change Procedure
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Cool the engine completely. Never open the cooling system when hot—serious burns can result.
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Remove the radiator cap (usually under the left shroud or just above the engine). Loosen it slowly to relieve any residual pressure.
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Place a drain pan beneath the engine. Locate the water pump at the lower right side of the engine. The drain bolt (typically an 8mm or 10mm bolt) is on the water pump cover.
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Loosen and remove the drain bolt. Allow all the coolant to drain out completely. Inspect the bolt and crush washer; replace if damaged.
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Optional flush: For maximum cleanliness, fill the system with distilled water, reinstall the drain bolt, run the engine briefly, then drain again. Repeat until clear.
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Reinstall the drain bolt and torque to manufacturer specification. Do not overtighten—the water pump cover is cast aluminum and can crack.
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Refill with fresh coolant using a funnel at the radiator cap. Fill slowly until the radiator core is covered.
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Burp the system: Gently rock the bike side-to-side and squeeze the radiator hoses to help evacuate trapped air.
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Start the engine and let idle for several minutes. Watch the coolant level drop as any air escapes. Top off as needed.
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Allow the engine to heat cycle until the thermostat opens (if equipped)—typically the lower radiator hose gets hot, and the coolant may flow visibly.
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Shut down and allow the bike to cool fully. Once cool, recheck coolant level and top off if necessary.
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Reinstall the radiator cap securely. Double-check for leaks at the drain bolt and along all hose connections.
Final Notes for 2011 TXT PRO 125 Owners
- Inspect the radiator fins for damage or clogging; clean gently as needed.
- Never overfill—too much coolant can cause overflow during heat cycles.
- If coolant level continues dropping after bleeding, check for leaks or possible trapped air.
- With the 2011+ engine and frame changes, always check for clearance and proper routing of hoses, especially after service.
- Ensure compatibility of parts; the kickstart shaft and water pump covers differ from some earlier TXT PRO models.
- After your first ride following coolant change, let the bike cool and recheck the level one more time.
Proper cooling system maintenance ensures your TXT PRO 125 runs cool and strong for every trial and every challenge—on and off the podium.
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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.