How to Change the Oil in a 2017 Yamaha YZ125

Shop parts for a 2017 Yamaha YZ125 Dirt Bike.

Changing the oil in your 2017 Yamaha YZ125 is a crucial maintenance task that keeps your dirt bike running at peak performance. This guide is brought to you exclusively by MotoSport.com and is designed to be comprehensive, step-by-step, and specific for the 2017 YZ125. Performing this job yourself saves money, increases your understanding of your machine, and ensures it's done right.

Tools and Materials Needed

  • Drain pan (to catch used oil)
  • 12mm socket and ratchet (for drain bolt)
  • 4mm Allen wrench (for check bolt)
  • Funnel (preferably a long-neck funnel)
  • Measuring cup (for oil volume accuracy)
  • Rag or shop towels
  • Replacement oil (recommended: 10W-40 with wet clutch compatibility, approximately 660 ml – 0.69 US quarts)
  • New drain bolt washer (recommended for best sealing and torque accuracy)
  • Torque wrench (recommended, but not strictly necessary)

Specifics for the 2017 YZ125

  • The oil fill cap is positioned beneath the exhaust pipe, so a long funnel makes the process much cleaner and easier.
  • The oil volume for a full change is 660 ml (0.69 US quarts).
  • The drain bolt uses a 12mm socket and should be torqued to 14 ft-lbs after reinstalling.
  • The oil type must be suitable for motorcycles with a wet clutch—look for gear oils or four-stroke engine oils that specifically note this compatibility.

Step-by-Step Oil Change Process

  1. Warm Up the Engine
    • Start the YZ125 and let it idle for 2–3 minutes. This helps suspend any contaminants in the oil and allows for a more complete drain.
    • Turn off the engine and secure the bike on a stand, making sure it is level.
  2. Drain the Old Oil
    • Locate the oil drain bolt underneath the crankcase.
    • Place your drain pan beneath the drain bolt.
    • Use a 12mm socket to carefully loosen and remove the drain bolt.
    • Allow all the oil to drain completely—this can take a few minutes.
    • If you have a new drain bolt washer, install it now to ensure a proper seal and torque cushion.
  3. Reinstall the Drain Bolt
    • Once the oil has drained, wipe the area clean with a rag.
    • Thread the drain bolt (with new washer) back in by hand to avoid cross-threading.
    • Tighten the bolt with your 12mm socket. If available, torque it to 14 ft-lbs for accuracy.
  4. Add New Oil
    • Remove the oil fill cap located above the clutch cover on the right side of the bike. This may be slightly obscured by the exhaust, so use a long funnel to avoid spills.
    • Pour in 660 ml (0.69 US quarts) of your chosen oil.
  5. Check the Oil Level
    • For the 2017 YZ125, you can use the oil check bolt (4mm Allen) to verify level after filling.
    • Add about half the required oil, then remove the check bolt. Slowly pour the rest in until you see oil begin to seep out of the check hole. This confirms the proper level.
    • Wipe off any drips and reinstall the check bolt and fill cap securely.
    • Clean around both bolts to ensure a dirt-free seal.
  6. Final Check
    • Start the engine and let it idle for a minute, then turn it off and check for any leaks around the drain or fill bolts.

Model-Specific Tips for the 2017 Yamaha YZ125

  • Drain bolt washer: Replacing the washer each oil change is highly recommended to ensure a proper seal and protect the threads on the crankcase.
  • Exhaust pipe proximity: Because the fill cap is tucked beneath the exhaust, a long and flexible funnel will prevent spillage and make the job much easier.
  • Oil recommendations: Use a gear oil or wet clutch-compatible four-stroke oil—avoid standard automotive oils that may not protect the transmission and clutch properly.
  • Oil volume: 660 ml (0.69 US quarts) is critical; too much can lead to leaks, too little impacts lubrication and clutch function.

Disposal and Environmental Responsibility

  • Dispose of used oil responsibly at a certified collection center.
  • Never pour oil onto the ground or into drains—protect both your bike and the planet.

With these steps, you can confidently change the oil on your 2017 Yamaha YZ125, ensuring smooth shifting and engine longevity on every ride. For more OEM parts, tools, and guidance, trust MotoSport.com—your authority for all things dirt bike maintenance.

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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.