How to Change the Oil in a 2018 Yamaha PW50: A MotoSport.com Exclusive Guide

Shop parts for a 2018 Yamaha PW50 Dirt Bike.

Changing the transmission oil in your 2018 Yamaha PW50 is a key maintenance task that improves longevity and performance, preventing premature wear. This dirt bike uses a separate transmission oil (not engine oil, as it is a two-stroke with premix or oil injection). The process is straightforward, takes under 20 minutes, and can be mastered by beginner mechanics with basic tools. Follow this proprietary step-by-step MotoSport.com guide to ensure the job is done right.

Tools and Supplies Needed

  • 12mm socket wrench
  • Drain pan for old oil
  • Measuring cup (for 0.30 L/0.32 qt oil)
  • Funnel
  • Fresh transmission oil (Type and spec per owner's manual – see below)
  • Crush washer or gasket (recommended, replace every oil change)
  • Rubber gloves (optional, for clean handling)
  • Rags or shop towels (for cleanup)

Recommended Transmission Oil & Quantities

  • Yamaha recommends: Refer to your owner's manual for the exact oil type. Most commonly, a high-quality 10W-30, 10W-40, or Yamaha Transmission Oil is specified. Do not use "CD" diesel spec oil or "ENERGY CONSERVING II" or higher specification oils, as this may cause clutch slippage.
    Amount: 0.30 L (0.32 US qt, 0.26 Imp.qt)

Step-by-Step Procedure

  1. Warm Up the Bike
    Start and idle the PW50 for a couple of minutes. This helps the oil drain faster and more completely by thinning it. Then, turn off the engine and ensure the bike is secure on level ground. Never perform oil changes with the engine running.
  2. Prepare Your Workspace
    Place your drain pan under the transmission drain bolt. Consider placing an absorbent mat or rags under the work area to catch any accidental drips.
  3. Remove the Transmission Oil Fill Cap
    Locate the oil fill cap on the right side of the transmission case. Remove it and set aside, keeping the area clean—this step ensures the oil drains freely.
  4. Remove the Drain Plug
    Using your 12mm socket wrench, carefully loosen and remove the transmission oil drain bolt at the bottom of the right engine case. Allow all oil to drain completely into your pan.
    Callout: The PW50 uses a crush washer or gasket on the drain bolt—always inspect for damage and replace it to prevent leaks, as recommended by Yamaha .
  5. Clean and Inspect Components
    Wipe down the drain bolt. Check the O-ring or crush washer for any nicks, flattening, or damage, and replace if necessary .
  6. Reinstall the Drain Plug
    Install the clean drain plug with a new crush washer/gasket. Tighten to the specified torque: 14 N·m (10 lb·ft) .
    Do not overtighten, as you can strip the threads in the soft aluminum case.
  7. Add New Transmission Oil
    With a funnel, pour in exactly 0.30 liters (0.32 US qt) of fresh, recommended oil through the fill port .
    Tip: Re-check the owner’s manual for your region to confirm quantity, as some versions may differ slightly.
  8. Replace and Tighten the Oil Fill Cap
    Make sure the fill cap O-ring is in good condition, then reinstall and snug the cap.
  9. Inspect for Leaks and Test
    Start the engine and let it idle for several minutes. While idling, inspect the drain and fill cap areas for leaks. If a leak is noticed, turn off the engine immediately and check that everything is properly torqued and sealed .
  10. Dispose of Used Oil Responsibly
    Pour the old oil into a sealed container and take it to a recycling center, auto shop, or hazardous waste facility.

Special Notes for the 2018 Yamaha PW50

  • Service Intervals: For new bikes, change the transmission oil after one month, then again at six months. For subsequent intervals, change once per year under normal use .
  • Oil Compatibility: Do not use oils with chemical additives or energy-conserving ratings, as this can lead to clutch slippage and potential damage .
  • Separate Injector Oil: The engine uses a separate two-stroke injector oil system, which must be checked and filled independently. This guide covers only the transmission oil. Always ensure the two-stroke injector oil tank is topped up and use Yamaha’s recommended injector oil .
  • Drain Plug Location: The transmission drain bolt is easily accessible at the bottom right of the engine. Always use a 12mm socket for removal .

Common Pitfalls & Pro Tips

  • Never overtighten the drain bolt—aluminum threads strip easily.
  • Replace the crush washer every time for leak-free operation.
  • Exact Filling: Use a measuring cup for oil—overfilling or underfilling affects clutch/performance.
  • Keep It Clean: Ensure dirt doesn’t enter the transmission while open—wipe around fill/drain ports first.
  • Record the Service: Note the date/mileage of the oil change for your maintenance log.

Conclusion

Following this exclusive MotoSport.com guide for changing the oil in your 2018 Yamaha PW50 ensures reliable operation and extends the life of your cherished mini dirt bike. Stick to Yamaha’s recommended oil specs, use the right tools, and pay attention to detail. If you require transmission oil, crush washers, or maintenance supplies, MotoSport.com offers OEM and high-quality aftermarket options to keep your PW50 performing at its best.

Related Shopping Categories

Shop Motor Oil for a 2018 Yamaha PW50 Dirt Bike.

Shop Oil Filters for a 2018 Yamaha PW50 Dirt Bike.

Shop Oil Drain Pans for a 2018 Yamaha PW50 Dirt Bike.

Shop Tools for a 2018 Yamaha PW50 Dirt Bike.

Shop Oil Fillers and Drain Plugs for a 2018 Yamaha PW50 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.