How to Change the Oil in a 2018 Yamaha YZ250FX

Shop parts for a 2018 Yamaha YZ250FX Dirt Bike.

Changing the oil on your 2018 Yamaha YZ250FX is an essential maintenance task that keeps your engine running strong and extends its lifespan. Below is a comprehensive, MotoSport.com proprietary guide with all the steps, tools, and specific tips you'll need for a pro-level oil change.

Tools & Supplies Needed

  • Socket wrench set (12mm and 8mm sockets recommended)
  • Oil drain pan
  • Torque wrench
  • Flathead screwdriver
  • New oil filter (OEM or aftermarket equivalent)
  • New crush washer for the drain bolt
  • Rags or paper towels
  • Yamalube 10W-40 or 10W-50 (check manual for viscosity recommendation based on climate)
  • Funnel
  • Gloves
  • Parts tray (helpful for organizing bolts)

Step-by-Step Oil Change Process

  1. Warm up the Engine
    • Start your 2018 YZ250FX and let it idle for 3-5 minutes. This helps the oil thin and makes it drain faster and more completely.
      Tip: Never rev the engine hard when the oil is cold; just let it idle.
  2. Stabilize the Bike
    • Place the bike on a stand or level ground so it stays vertical during the process.
  3. Remove the Skid Plate (if equipped)
    • If your bike has an aftermarket or stock skid plate, use your socket or screwdriver to remove it for easier access to the drain bolt.
  4. Remove the Oil Filler Cap
    • Loosen and remove the oil filler cap to help the oil drain freely and avoid vacuum build-up.
  5. Drain the Engine Oil
    • Place your oil drain pan under the drain bolt, located beneath the engine block. Use your 12mm socket to loosen and remove the bolt.
    • Allow oil to fully drain.
      Model Note: The YZ250FX has an oil sight glass on the right side. Refer to it when filling after the change to ensure correct levels.
    • Inspect and clean the oil strainer (screen) if your model has one. Remove it according to your manual and rinse with brake cleaner or solvent, then reinstall.
  6. Remove and Replace the Oil Filter
    • The oil filter cover is on the right side of the engine. Use an 8mm socket to remove the bolts securing the cover.
    • Remove the old filter and the big cover O-ring. Clean the seating surfaces. Install the new O-ring (light coat of oil helps with sealing) and new filter, inserting it in the same direction as the old one.
  7. Replace the Crush Washer and Reinstall the Drain Bolt
    • Install a brand new crush washer on the drain bolt to prevent leaks. Tighten the drain bolt to Yamaha-recommended torque spec (check manual, typically around 18 ft-lbs).
  8. Refill with Fresh Oil
    • Using a clean funnel, pour fresh oil into the filler port.
    • 2018 Yamaha YZ250FX typical oil capacity (with filter change): 1.10 liters (1.16 US qt)–confirm exact amount in your manual.
    • Stop periodically to check the oil sight glass, aiming for the oil level to sit between the upper and lower marks when the bike is vertical.
  9. Start and Check for Leaks
    • Reinstall the oil filler cap securely.
    • Start the engine and let it idle for a few minutes. Shut it off and check for leaks at the drain bolt and oil filter cover.
    • Allow the oil to settle, then recheck level in the sight glass, adding a little oil if necessary.
  10. Final Cleanup and Disposal
    • Clean up tools and spilled oil. Properly dispose of used oil and filter at a recycling center or auto parts store.

2018 Yamaha YZ250FX Model-Specific Call-Outs

  • Oil Capacity: Approximately 1.10 liters including filter. Avoid overfilling.
  • Sight Glass: Use the right-side sight glass to check the oil level after refilling. Level should be checked with the bike upright, engine warmed, and after waiting a few minutes for oil to settle.
  • Drain Bolt Location: 12mm bolt underneath the engine. Always use a new crush washer for best sealing.
  • Oil Strainer: Clean the oil strainer screen at the bottom of the engine every oil change for optimal engine protection.
  • Filter Installation: Lubricate the filter’s O-ring with a bit of fresh oil to ensure a proper seal.
  • Tightening: Do not overtighten drain bolt or oil filter cover bolts—use a torque wrench for accuracy.

Extra Pro Tips

  • Record the date and hours on a sticker or log for easy service tracking.
  • If you ride in severe conditions (mud, sand, racing), change oil more often than the manual’s interval.
  • Always use a high-quality, motorcycle-specific synthetic or semi-synthetic oil for best clutch and engine performance.

Performing an oil change yourself not only saves money but also gives you a look inside your engine’s health every time you drain the oil. Stay ahead of maintenance—and keep your YZ250FX running at its best—by wrenching with confidence using this MotoSport.com guide.

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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.