How to Change the Coolant in a 2018 Beta 390 RR-S: MotoSport Guide

Shop parts for a 2018 Beta 390 RR-S Dirt Bike.

Keeping the coolant fresh in your 2018 Beta 390 RR-S ensures optimal engine performance and longevity, especially under demanding riding conditions where the bike is prone to generating heat. This step-by-step MotoSport guide will help you replace the coolant safely and effectively, while also sharing key model-specific tips every 390 RR-S owner should know.

Tools & Supplies Needed

  • Fresh coolant (use a high-quality brand rated for aluminum engines)
  • Basic hand tools (screwdriver, pliers, sockets)
  • Catch pan
  • Funnel
  • Protective gloves
  • Clean water (for flushing, optional)
  • Shop towels

Step 1: Prep the Bike

  • Allow the engine to cool completely. Opening a hot cooling system risks burns from steam or hot fluids.
  • Stand the bike securely on a level surface using the kickstand or a bike stand.

Step 2: Drain the Old Coolant

  • Remove the seat and right side shroud for easy access to the radiator cap.
  • Place your catch pan under the water pump or lowest radiator hose connection.
  • Slowly open the radiator cap to release pressure.
  • Locate the coolant drain bolt on the water pump or disconnect the lower radiator hose. Allow all coolant to drain completely.

Step 3: Optional – Flush the System

  • For optimal maintenance, flush the system with clean water to remove any old coolant residue.
  • Reconnect the drain, fill the system with clean water, run the engine for a minute, then drain again.
  • Repeat if fluid contains visible debris or discoloration.

Step 4: Reinstall and Fill

  • Reattach the lower hose or drain bolt securely. Double check hose clamps, as improper installation can cause leaks – especially important on the Beta 390 RR-S due to tight clearances near the radiator bottom.
  • Slowly add new coolant through the radiator neck using a funnel, filling to just above the radiator core.

Step 5: Bleed the Cooling System

  • Beta models like the 2018 390 RR-S typically do not include a radiator bleeder screw. Instead, use this technique:
    • With the radiator cap off, gently rock the bike side to side and tap radiator hoses to help trapped air escape.
  • Watch for air bubbles rising as the coolant settles. Top off coolant as needed.

Step 6: Reassemble – Run the Engine

  • Reinstall the radiator cap and bodywork. Start the engine and let it idle until it gets up to temperature (until the fan kicks on, if equipped).
  • Turn the engine off and let it cool completely. Remove the radiator cap and recheck the coolant level, topping off as necessary.
  • Check the overflow reservoir as well, keeping the fluid level between the min and max marks.

Step 7: Final Checks

  • Inspect for leaks around all hoses and the drain bolt. Pay close attention to the area near the gearshift side radiator hose – previous owners have noted improper seating can cause leaks if the hose or clamp isn't refitted fully.
  • Confirm the coolant level after your next ride and periodically thereafter.

Model-Specific Notes for the 2018 Beta 390 RR-S

  • This model uses a closed aluminum radiator system that benefits from a quality coolant formulated for aluminum. While standard coolant works fine if the system is well-maintained, those riding in consistently high heat or slow trails might consider a high-performance coolant for improved temperature control.
  • Factory fans are a common upgrade due to the bike's tendency to run hot in the woods or technical terrain. If your bike is fan-equipped, double check your wiring and operation after coolant service.
  • Unlike older Beta models, the 2018 RR-S no longer has a dedicated radiator bleeder screw – so fully burping the system is a must.

Pro Tips

  • Change coolant annually for best results or more frequently if riding in extreme conditions.
  • Always dispose of used coolant safely – it's highly toxic to animals and the environment.
  • Keep a small amount of spare coolant handy for topping off after your first post-service ride.

Routine coolant changes aren't just maintenance – they're insurance for performance and long engine life on your Beta 390 RR-S. Ride safe and enjoy the trails.

Related Shopping Categories

Shop Radiators for a 2018 Beta 390 RR-S Dirt Bike.

Shop Coolant for a 2018 Beta 390 RR-S Dirt Bike.

Shop Temperature Sensors for a 2018 Beta 390 RR-S Dirt Bike.

Shop Tools for a 2018 Beta 390 RR-S Dirt Bike.

Shop Radiator Hoses for a 2018 Beta 390 RR-S Dirt Bike.

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.