How to Change the Coolant in a 2026 Beta 390 RS: MotoSport Exclusive Guide

Shop parts for a 2026 Beta 390 RS Dirt Bike.

Regular coolant maintenance is essential for the performance and longevity of your 2026 Beta 390 RS. This exclusive MotoSport.com guide details each step to safely change your coolant and highlights key notes unique to this Beta model.

What You Need

  • Recommended coolant for aluminum engines (see Beta's manual for specs)
  • Distilled water for flushing (optional but recommended)
  • Sockets or screwdrivers for fairing and engine guard removal
  • Drain pan
  • Protective gloves and eyewear
  • Torque wrench
  • Rags for cleanup

Important Safety Notes

  • Only change coolant when the engine is cold to prevent burnsDanger of burning.
  • Wear gloves and protective clothing. Coolant is toxic; avoid skin, eye, and mouth contact.
  • Dispose of old coolant responsiblydo not pour it down drains. Use an automotive recycling center.

Drain the Old Coolant

  1. Place your 390 RS upright on stable ground.
  2. Remove necessary body panels or the engine skid plate for access. Use your tools to loosen and set aside the fasteners.
  3. Locate the radiator capdo not open it yet.
  4. Position a drain pan under the engine near the coolant drain bolt (typically on the water pump cover).
  5. Carefully loosen the drain bolt and allow the coolant to flow completely into the pan. If equipped, also loosen the bleed screw on the cylinder or radiator for better drainage.
  6. Once drained, reinstall the drain bolt with its sealing washer, torquing to the value prescribed in your owner's manual (usually 10Nm, but verify for your year/model).

Flush the System (Recommended)

  1. Reinstall the drain bolt and fill the radiator with distilled water.
  2. Start the engine and let it idle until it nears operating temperature or the fan cycles on. Shut off and cool completely.
  3. Repeat drain steps to remove the rinse water. Continue until the flush water runs clear, typically two flushes are sufficient.

Refill with New Coolant

  1. Ensure all drain/bleed bolts are secured and torqued.
  2. Pour the recommended coolant into the radiator until it reaches the base of the filler neck. If your model has a bleed screw, loosen it as you fill to release air, then retighten when coolant appears.
  3. Install the radiator cap securely.
  4. Start the engine and allow it to reach operating temperature, watching for leaks and ensuring the fan cycles on. This helps purge air from the system.
  5. Shut down and let cool. Once fully cooled, re-check coolant level and top off as needed.
  6. Check the coolant reservoir (if equipped) and fill to the indicated line.

Model-Specific Tips for the 2026 Beta 390 RS

  • The 390 RS is known for a compact, high-performance engine that runs warmer compared to larger displacement Betaskeeping the cooling system in top shape is crucial for performance and engine longevity.
  • If you ride technical trails or at low speeds, consider installing a radiator fan kit, as these bikes can heat-soak in slow terrain. Maintaining fresh coolant optimizes fan effectiveness.
  • Consult your owner's manual for coolant capacity and recommended type, and always use products designed for aluminum engines to prevent corrosion.
  • Check hoses and clamps for leaks or aging during each coolant change, as vibration on single-cylinder dirt bikes can loosen fittings over time.

After Service: Final Checks

  • Inspect for leaks and monitor the coolant level after your next rideair pockets can release after a few heat cycles, requiring a small top off.
  • Examine both the radiator and reservoir. The coolant should always be visible at the base of the neck when cool; the reservoir should be on the marked line.

Changing the coolant is a fast, rewarding service you can perform at home–keeping your 2026 Beta 390 RS running at peak performance ride-after-ride. For replacement parts, coolants, and specialty tools, MotoSport carries everything you need for your BetaShop parts for a 2026 Beta 390 RS Dirt Bike.

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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.