How to Change the Coolant in a 2021 GAS GAS MC 85

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The 2021 GAS GAS MC 85 is designed for competitive youth motocross racing, and keeping the cooling system in top condition is vital for reliable performance. Use these step-by-step instructions for changing the coolant – an essential part of cooling system maintenance – to prevent overheating and protect the engine.

What You Need

  • Correct type of engine coolant (refer to your manual or use a high-quality premix that is safe for aluminum engine components)
  • Drain pan
  • Allen wrenches or sockets (as required for drain bolt and radiator cap)
  • Funnel
  • Rags and safety gloves

Before You Begin

  • Ensure the engine is completely cool before opening the cooling system. Hot coolant can cause severe burns.
  • Work in a well-ventilated area and avoid skin contact with the coolant.

Step-by-Step Guide

  1. Remove the radiator cover: Locate and remove the fasteners securing the radiator cover on either side to access the radiator cap and main cooling lines.
  2. Drain the old coolant:
    • Position your drain pan under the right-side engine case, where the coolant drain bolt is located (usually on the water pump).
    • Remove the radiator cap first to break the vacuum and assist draining.
    • Remove the drain bolt and allow all coolant to drain out. Carefully loosen any bleeder screws near the cylinder head, if equipped, to help with draining and bleeding air.
  3. Inspect and flush the system (optional):
    • If the coolant is especially dirty, flush the system using distilled water. Pour distilled water into the radiator, reinstall drain bolt, run the engine briefly, then drain.
  4. Reinstall the drain bolt: Replace the copper washer if necessary to avoid leaks. Tighten the drain bolt securely but do not overtighten.
  5. Add new coolant:
    • Use a funnel to slowly pour new coolant into the radiator or main fill port. Fill until coolant is level with the bottom of the radiator neck.
    • Loosen the cylinder head bleeder screw briefly to allow any trapped air to escape, then retighten when only coolant flows.
    • Gently squeeze radiator hoses to help evacuate remaining air bubbles.
  6. Reinstall the radiator cap:
    • Double-check that all bolts, screws, and the radiator cap are securely back in place.
  7. Run the engine and recheck:
    • Start the MC 85 and let it idle for a couple of minutes. Watch for leaks and monitor the coolant level.
    • Shut off the engine, allow it to cool completely, and check the coolant level again. Top off if necessary to ensure it sits at the correct level.
  8. Replace radiator cover and check for proper operation.

Important Notes for the 2021 GAS GAS MC 85 Owner

  • Do not use tap water when mixing coolant as minerals can cause deposits and corrosion inside the system.
  • The MC 85’s high-revving two-stroke engine runs hot under load – keeping the coolant fresh is especially crucial after muddy races or long practice sessions.
  • If the bike has overheated or the coolant looks contaminated, inspect the water pump and hoses for leaks or worn parts; replace as needed from MotoSport.
  • Always properly dispose of used coolant; it is poisonous and must not be poured onto the ground or into drains.

Maintenance Tips

  • Check coolant level before every ride, especially during racing season or after extreme riding conditions.
  • Follow the service manual intervals for routine coolant changes – typically every 12 months or after extended storage.
  • If you ride in freezing temperatures, make sure the coolant provides adequate antifreeze protection.

Keeping the cooling system in excellent shape ensures your 2021 GAS GAS MC 85 runs at its best all season.

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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.