How to Change the Coolant in a 2021 GAS GAS TXT RACING 300
Shop parts for your ride now!The 2021 GAS GAS TXT RACING 300 is a specialized trials dirt bike designed for expert performance and reliability. Regular coolant changes are essential for optimal engine performance and longevity, particularly for a high-performance trials bike where low-speed operation and extended idling can make engine temperature management critical. This step-by-step procedure is tailored to the unique design of the TXT RACING 300 so you can confidently maintain your machine.
What Makes the TXT RACING 300 Unique?
- Light clutch pull and reliable transmission – ideal for technical trials riding and frequent gear changes.
- Intermittent fan operation – active cooling keeps engine temperature stable during low airflow conditions.
- Compact frame – access to critical components like the radiator and hoses may require removal of bodywork or the gas tank for service.
Coolant loss is rare when the cooling system functions correctly, but dirty or depleted coolant can cause overheating and potential engine damage. DOT-appropriate, high-performance coolant is recommended for consistent results and protection.
What You'll Need:
- Fresh coolant (ethylene glycol-based, or as specified in your owner's manual)
- Distilled water (if diluting concentrate)
- Drain pan
- Socket set or screwdriver (for radiator cap and hose clamps)
- Funnel
- Clean rag
- Gloves and eye protection
Step-by-Step Coolant Replacement Guide
- Let the engine cool completely.
Never open the radiator cap or drain coolant when the engine is hot—serious burns can result. - Remove the seat and gas tank (if necessary).
On the TXT RACING 300, cramped frame geometry sometimes requires removing the seat and the fuel tank for easier access to the radiator and hoses. - Position the drain pan.
Place a pan under the engine to catch the old coolant. - Drain the coolant.
Locate the lower radiator hose or dedicated coolant drain bolt on the water pump. Loosen the hose clamp and carefully disconnect the hose from the water pump, or remove the drain bolt if equipped. Allow the coolant to fully drain.
Pro tip: A small metal shim may be present behind the brass drain bolt on some models—do not lose this when draining. - Flush with distilled water (optional but recommended).
Reattach the hose/bolt, fill the system with distilled water, and run the engine for a minute (without the radiator cap) to flush debris. Let cool, then fully drain. - Reinstall drain bolt or hose. Ensure a snug, leak-free fit. Replace any worn hose clamps if needed.
- Refill with fresh coolant.
Using a funnel, slowly add new coolant to the radiator up to the recommended level. Gently rock the bike side to side to help dislodge air bubbles. Some owners use a 60/40 mix of coolant and distilled water for optimum heat transfer, but always follow the specifications in your owner's manual for your climate conditions. - Bleed the cooling system.
Start the engine and let it idle with the radiator cap off until the thermostat opens and air bubbles stop emerging. Top up as necessary. Replace the cap securely. - Check for leaks and reassemble.
Inspect all connections for leaks. Reinstall the gas tank and seat. - Dispose of old coolant responsibly.
Never pour coolant down the drain or on the ground—take it to a recycling or hazardous waste center.
Noteworthy Tips for 2021 TXT RACING 300 Owners
- Fan activation is normal, especially at low speed—the system is designed to regulate temperature automatically.
- Avoid using just water alone, even in emergencies. Always use a recommended blend or premixed coolant engineered for off-road motorcycles.
- Keep an eye on coolant level and color. Any drop in level or discoloration can signal a minor leak or head gasket issue which is not common but should never be ignored.
Proper maintenance of your 2021 GAS GAS TXT RACING 300 cooling system ensures you can focus on mastering technical sections without worry—ride with confidence and keep your trials machine running strong.
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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.