How to Change the Coolant in a 2021 Sherco 300 SEF FACTORY

Shop parts for a 2021 Sherco 300 SEF FACTORY Dirt Bike.

Routine coolant changes are critical to keeping your 2021 Sherco 300 SEF FACTORY running cool and maintaining engine reliability. This model features a liquid-cooled four-stroke powerplant and a high-performance aluminum radiator system–proper service is essential due to the tight tolerances and advanced materials. Below you will find a step-by-step proprietary MotoSport guide for changing your coolant with special notes for your specific dirt bike.

What You Need

  • Approved motorcycle coolant (Minerva Perma Universal D 4 or comparable, rated to at least –25°C)
  • Basic socket set
  • Screwdrivers
  • Drain pan
  • Torque wrench
  • New bleed screw and drain bolt gaskets (recommended)
  • Clean funnel
  • Shop towels
  • Personal protective gear (gloves, eyewear)

Preparation

  • Ensure your Sherco 300 SEF FACTORY is on a level surface using a bike stand. Allow the engine to cool completely before servicing.
  • Remove the radiator shrouds if easier access to the fill and bleed screws is needed.

Draining the Coolant

  • Place your drain pan under the water pump area on the lower left side of the engine.
  • Carefully loosen the radiator cap to release any built-up pressure.
  • Remove the coolant drain bolt at the water pump housing. Allow coolant to completely drain into your pan. Properly dispose of old coolant at an approved collection center–never pour it down a drain or on the ground.

Flushing (Optional Yet Recommended)

  • If the old coolant appears dirty or contaminated, briefly refill the system with distilled water, reinstall bolts, run the engine to circulate, then drain again before proceeding.

Filling the Cooling System

  • Reinstall and torque the drain bolt with a new gasket to the specified 6Nm.
  • Remove the radiator cap and the bleed screw (M6x8) located on the left radiator tank.
  • Slowly pour coolant into the radiator fill until liquid emerges bubble-free from the bleed screw. Once bubbling stops, reinstall the bleed screw with a new gasket and torque to 8Nm.
  • Continue to fill until the fluid nearly reaches the top of the radiator, or until the level is at the indicator mark if equipped.

Final Checks

  • Reinstall the radiator cap securely.
  • Start the engine and let it idle for several minutes with the bike upright. Blip the throttle a few times to clear any air bubbles–stop the engine and let it fully cool.
  • Check the coolant level again. Top off as necessary until it is at the LEVEL mark.
  • Visually inspect all hoses and hose clamps for leaks or cracks. Tighten or replace as needed.

Important Model-Specific Notes

  • Only use approved coolant types–water or automotive antifreeze can cause corrosion or overheating.
  • The Sherco 300 SEF FACTORY cooling system capacity is approximately 1.1 liters.
  • If you notice coolant weeping from the pump housing, the water pump seal may be faulty and must be replaced; this requires additional disassembly including clutch cover removal. Avoid operating the bike if coolant loss is detected–engine damage can occur quickly.
  • Routinely check radiator fins for bends or blockage, as this model's radiator design is compact and may impact cooling if airflow is restricted.

By following this proprietary MotoSport process, you maintain your Sherco's legendary reliability & protect its competition-winning power. Happy riding.

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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.