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

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

The Beta 390 RR-S is a standout in the dual-sport world, known for its Italian engineering, lightweight feel, and rugged reliability. To keep your 2018 engine and transmission running smoothly, regular oil changes are crucial. This model features two separate oil systems–engine and transmission–making the process unique compared to single sump dirt bikes. Below you'll find the MotoSport.com step-by-step guide, including proprietary tips for the best care.

What You Need

  • Beta oil change kit (includes oil filters, o-rings)
  • Liqui Moly 10W-50 or Beta-recommended oil
  • Drain pan
  • 13 mm socket for engine drain bolt
  • 8 mm socket for oil filter cover bolts

Prep – Unique to Beta 390 RR-S

  • Remove the skid plate to access the drain bolts.
  • This model uses two drain bolts: one for the engine, one for the transmission.
  • Beta RR-S bikes use a split lubrication system–engine and transmission oil is filled and checked independently.

Step-by-Step Instructions

  1. Warm up the bike for a few minutes. Letting the oil flow ensures a more complete drain and removes particulates.
  2. Remove the skid plate and place your drain pan under the bike.
  3. Remove the oil filter cover: Use an 8 mm socket, pull the cover, then remove the oil filter and cover o-ring.
    Tip: Leave the oil filter cover off to promote better oil drainage.
  4. Remove the engine oil drain bolt (13 mm socket) and allow oil to fully drain into pan.
  5. Remove the transmission oil drain bolt and let transmission oil completely drain.
  6. Install new o-rings on both drain bolts and the oil filter cover.
  7. Replace oil filter making sure the open end faces the engine. Put in new oil filter cover o-ring and reinstall cover. Tighten filter cover bolts to 10 Nm.
  8. Reinstall drain bolts. Torque engine drain bolt to 15 Nm, transmission drain bolt to 20 Nm.
  9. Refill with oil:
    • Engine: 750 ml Liqui Moly 10W-50
    • Transmission: 750 ml Liqui Moly 10W-50
    Replace oil filler cap o-rings too.
  10. Start the bike for 2 minutes, then check oil levels:
    • Engine oil: Check while running–the level should be in the middle of the sight window.
    • Transmission oil: Check with the check bolt–level should be at the bottom of the threads.
    Add or remove oil as needed to reach correct levels.
  11. Reinstall the skid plate and check for leaks.

Important Beta 390 RR-S Owner Notes

  • This bike uses two independent oil systems–always service both the engine and transmission sides for every oil change.
  • Beta recommends checking engine oil level while the bike is running–this is unlike most other brands, so do not check when off.
  • Oil sight glass readings may vary after riding due to oil circulation; check as specified above for reliable measurement.
  • Overfilling either sump can cause performance issues or leaks; never exceed 750 ml per side.
  • If your riding style is aggressive or you ride in harsh conditions, consider shorter intervals between oil changes to prolong engine life.

Your 2018 Beta 390 RR-S is designed for performance and longevity when maintained properly. Regular oil changes are the key to keeping your dirt bike delivering reliable power on the trails and roads alike.

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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.