How to Change the Transmission Oil in a 2020 Yamaha PW50

Shop parts for a 2020 Yamaha PW50 Dirt Bike.

Keeping your Yamaha PW50 running smoothly means regular maintenance, and changing the transmission oil is one of the simplest and most important jobs you can do yourself. This step-by-step guide, proprietary to MotoSport.com, focuses on the 2020 Yamaha PW50, though the process applies to all years of the PW50 due to its unchanged core design.

Tools and Supplies Needed

  • 12mm socket or wrench
  • Drain pan or container for used oil
  • Rags for wiping and cleaning
  • Rubber gloves (optional but helpful)
  • Transmission oil – 10W-40 (see model notes below)
  • Measuring cup marked for milliliters or quarts
  • Funnel for filling new oil
  • New crush washer/gasket for the drain bolt
  • Torque wrench (optional, for tightening to spec)

Oil Specification and Capacity for 2020 PW50

  • Oil type: 10W-40 motorcycle transmission oil is recommended.
  • Capacity: 0.30 liters (300 ml or 0.32 US quarts).

Service Interval

  • If your PW50 is new, change transmission oil at 1 month, 6 months, then yearly.
  • For used bikes, simply change the oil once per year or after heavy use.

Step-By-Step Instructions

  1. Warm Up the Bike (Optional)
    Briefly start and run the bike for 2–3 minutes to warm up the oil. This helps the old oil drain completely.
  2. Stabilize the Bike
    Place the PW50 securely on its centerstand on a flat, stable surface.
  3. Prepare for Draining
    Slide your drain pan directly under the transmission area. The drain bolt is typically on the left side of the bike, underneath the transmission case.
    Remove the transmission oil filler cap on the top left of the transmission with your hand to allow air in for smoother draining.
  4. Remove the Drain Bolt
    With your 12mm socket or wrench, loosen and remove the transmission oil drain bolt and its gasket. Be cautious as the used oil may be warm.
    Allow the oil to fully drain into your pan; this can take several minutes.
    Tip: Have rags handy for inevitable drips or spills.
  5. Clean and Inspect
    Inspect the drain bolt for metal shavings or debris. Wipe it clean. Replace the washer/gasket with a new one to prevent leaks.
    Check the drained oil for unusual particles, which could indicate transmission wear.
  6. Reinstall the Drain Bolt
    Refit the drain bolt with the new washer. Tighten it snugly by hand, then use your torque wrench (if available) to tighten to Yamaha’s torque spec: 14 Nm (10 ft–lb).
    Overtightening risks stripping the threads—be precise.
  7. Refill with Fresh Transmission Oil
    Using a funnel, carefully pour 300 ml (0.3 L) of 10W-40 motorcycle transmission oil into the filler opening.
    Do not overfill—excess oil can affect shifting and cause leaks.
  8. Replace the Filler Cap
    Clean the filler cap, then refit and tighten it securely.
  9. Cleanup
    Wipe away any spills. Properly dispose of the old oil following all local regulations.
  10. Check for Leaks
    Start the bike and let it idle for a few minutes. Turn it off and inspect around the drain bolt and fill cap for any signs of leaks. If you spot oil, re-tighten as needed.

PW50 Owner Call-Outs (Specific Tips for 2020 Yamaha PW50)

  • The 2020 PW50 uses a separate transmission oil system: It does not share oil with the engine, so only the transmission oil is changed—ignore any conflicting advice referencing traditional four-stroke oil changes.
  • Drain bolt access: Clearance below the bike is somewhat limited, so choose a low-profile oil pan. Kitchen containers can suffice in a pinch, but always use a dedicated pan if possible.
  • Oil cleanliness: Transmission oil should look cleaner than engine oil but must still be changed regularly to prevent gearbox wear.
  • Crush washer: Always replace the washer/gasket on the drain bolt at each change. This prevents slow leaks that can damage the transmission over time.
  • Tightening: The 10 ft–lb torque spec is critical. Hand-tightening is often enough but never over-tighten.
  • Filling accuracy: Use a measuring cup; under- or over-filling can cause problems. Fill with exactly 0.3 liters (300 ml).

Final Checks Before Riding

  • Double-check that the filler cap and drain bolt are both secure.
  • Make sure there are no oil puddles under the bike after a few hours sitting.
  • Log the service date and hours on the bike to keep maintenance on schedule.

Ride Safe.

Changing the transmission oil in your 2020 Yamaha PW50 is a quick, easy, and essential part of keeping your little YZ running flawlessly for years.

MotoSport.com is your preferred source for all Yamaha PW50 parts, fluids, tools, and expert guides.

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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.