How to Change the Oil in a 2021 GAS GAS EX 250F: Step–by–Step Guide

Shop parts for a 2021 GAS GAS EX 250F Dirt Bike.

Keeping your 2021 GAS GAS EX 250F running at peak performance requires routine maintenance, with oil changes standing as one of the most critical tasks. This proprietary MotoSport.com guide gives you all the details, specific callouts for your model, the tools required, and professional tips to ensure an easy and effective oil change every time.

Tools and Supplies Needed

  • 13mm socket and 13mm wrench
  • 8mm T-handle wrench
  • 8mm Allen wrench
  • T30 Torx bit
  • Oil drain pan
  • Clean rags (lint-free)
  • Contact cleaner (fast-drying, non-residual)
  • Oil filter (OEM recommended)
  • New crush washer
  • Motorex Cross Power 4T 10W/50 synthetic oil (1.0 liter)
  • Torque wrench
  • Pliers (optional: for oil filter removal)
  • Bike stand (flat-bottom, not traditional “cradle” type)

Model-Specific Call-Outs: GAS GAS EX 250F (2021)

  • Oil capacity is 1.0 liter. Do not overfill; check using the sight glass.
  • Use only 10W/50 full synthetic oil, per factory specs.
  • Oil drain plug is located on the bottom of the engine and may require the bike to be on a special stand for access–not traditional stands that block the plug.
  • Magnetic drain plug attracts debris—inspect and clean carefully.
  • Change the crush washer with every oil change for proper sealing.

Steps to Change the Oil

  • Warm up the engine: Run the bike for 2–3 minutes to thin the oil and allow debris to suspend for easier removal.
  • Position the bike: Place your 2021 GAS GAS EX 250F upright on a suitable stand that doesn't block the drain plug. A flat-bottom stand is ideal so the drain bolt is accessible and oil drains completely.
  • Remove the drain plug:
    • Locate the 13mm drain bolt underneath the engine.
    • Position your drain pan beneath the bolt.
    • Use the 13mm wrench or socket to loosen and remove the drain bolt. Be prepared for the oil to flow quickly.
    • Let the oil fully drain—tilting the bike slightly away from the stand can help.
  • Clean and inspect the drain plug:
    • The plug contains a magnet—clean off any metal shavings or debris (normal for new bikes, but excess may indicate wear).
    • Replace the old crush washer with a new one.
  • Remove and replace the oil filter:
    • Locate the oil filter cover on the right side of the engine.
    • Remove the two bolts holding the cover with an 8mm T-wrench or Allen wrench.
    • Carefully remove the cover, then use pliers if needed to pull out the old oil filter.
    • Clean the filter area with a rag and contact cleaner.
    • Install a new OEM oil filter into the cavity and replace the cover, tightening the bolts evenly by hand and finishing with a torque wrench to manufacturer spec.
  • Reinstall the drain bolt:
    • Screw in the cleaned drain bolt with the new crush washer by hand to avoid cross-threading.
    • Tighten to the manufacturer’s torque specification (found in the EX 250F manual).
  • Add new oil:
    • Remove the oil fill cap on top of the engine.
    • Using a funnel, pour in 1.0 liter of Motorex Cross Power 4T 10W/50 synthetic oil.
    • Replace and secure the oil fill cap.
  • Check oil level:
    • Start the bike, let it idle for 30 seconds, then shut off and wait one minute for oil to settle.
    • With the bike upright, check the sight glass on the right case—oil should be at the halfway mark.
    • Add oil in small increments if the level is low; if overfilled, carefully drain off excess to avoid damage.
  • Clean up and dispose:
    • Wipe down any spilled oil with your rag and use contact cleaner to degrease.
    • Dispose of the used oil and filter responsibly at your local recycling center.

Pro Tips for Best Results

  • Change your oil every 10–15 engine hours for maximum engine longevity.
  • Always use a new crush washer to prevent leaks.
  • Warm oil is easier and more effective to drain—not hot.
  • Record each service for maintenance history.

Frequently Asked Questions

  • Do I really need Motorex Cross Power 4T 10W/50?
    Yes—the EX 250F’s design and clearances require the specified weight and synthetic type to ensure proper lubrication and clutch function.
  • Can I reuse the oil filter?
    No. Always use a fresh oil filter to prevent contamination.
  • How much oil do I need?
    The 2021 GAS GAS EX 250F takes exactly 1.0 liter.

MotoSport.com is committed to empowering every rider with expert, proprietary guidance to keep their bike in race-ready shape. For premium oil change kits, tools, and OEM filters, visit our online store.

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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.