How to Change the Oil in a 2021 Yamaha YZ250FX

Shop parts for a 2021 Yamaha YZ250FX Dirt Bike.

Changing the oil in your 2021 Yamaha YZ250FX is a key part of keeping your dirt bike running at peak performance. Below you'll find everything you need to know, straight from the MotoSport.com experts, to get the job done right and keep your YZ250FX in race-ready condition.

Tools and Supplies Needed

  • Engine oil (Yamalube recommended, viscosity SAE10W-40 or SAE10W-50, JASO MA standard)
  • New oil filter (model-specific)
  • Oil drain pan
  • 12mm socket or wrench (for drain bolts)
  • Ratchet or spanner
  • Gloves (recommended)
  • Funnel (for pouring new oil)
  • Shop towels or rags (for spill cleanup)
  • Torque wrench (recommended for precise bolt tightening)
  • Replacement crush washers (for drain bolts)
  • Flathead screwdriver (for removing oil filter cover, if necessary)
  • Optional: Measuring cup, clear oil container (to examine oil condition), and nitrile gloves for cleaner work

Step-by-Step Process

  • 1. Warm Up Your Engine
    Start your YZ250FX and let it idle for a few minutes. Warm oil flows better and carries out more debris. Then turn off the engine and let it sit for about five minutes to allow oil to settle.
  • 2. Position the Bike
    Set the bike upright using a stand. This keeps the engine level for proper draining.
  • 3. Remove Oil Filler Cap
    Loosen and remove the oil filler cap on top of the engine to vent the system–this ensures a smooth oil flow during draining.
  • 4. Position the Drain Pan
    Place an oil drain pan under the engine on the clutch side. For the YZ250FX, the main oil drain bolt is a 12mm bolt located at the rear base of the engine.
    Tip: Use a clear container to catch the oil so you can inspect it for contaminants such as coolant or excess metal shavings.
  • 5. Remove Drain Bolt(s)
    Carefully loosen and remove the main drain bolt using a 12mm socket. Allow the old oil to completely drain into the pan. Inspect the drain bolt for metal debris and replace the crush washer if needed.
    The 2021 YZ250FX also features an oil filter drain bolt just below the oil filter cover; remove this to drain excess oil from the filter cavity as recommended.
    If equipped, remove and clean the oil strainer screen.
  • 6. Remove and Replace the Oil Filter
    Using a ratchet or appropriate screwdriver, remove the bolts securing the oil filter cover (right side of the engine). Pull off the cover, being careful not to lose the O-ring. Remove the used oil filter and discard it.
    Clean the cover and O-ring. Replace the O-ring if it is brittle, cracked, or damaged. Install a new, model-specific oil filter into the housing. Reinstall the cover, tightening bolts evenly to prevent leaks.
  • 7. Reinstall Drain Bolts
    Once the oil has fully drained, reinsert the drain bolt(s) with new crush washers. Tighten to Yamaha–s recommended torque specification to avoid over-tightening or stripping the threads.
  • 8. Add New Oil
    Insert a clean funnel into the oil fill hole. Pour in the proper amount of new oil as specified in your owner–s manual (Yamaha YZ250FX typically requires approximately 1.1L with filter change).
    Check your manual for the exact specification for your year and model.
  • 9. Check the Oil Level
    Reinstall the fill cap loosely. Start the bike and let it idle for about 30 seconds, then shut off and let it sit for a minute to allow oil to settle. Remove the fill cap and check the oil level using the oil level sight glass or dipstick.
    Add oil as needed to reach the correct level; avoid overfilling.
  • 10. Final Inspection and Cleanup
    Double-check all bolts and the oil filter cover for tightness. Wipe off any oil spills and ensure there are no leaks. Properly dispose of the used oil and filter according to local regulations.

2021 YZ250FX-Specific Callouts