How to Change the Oil in a 1998 Honda CR250

Shop parts for a 1998 Honda CR250 Dirt Bike.

Changing the oil in your 1998 Honda CR250 is a routine maintenance task that keeps your dirt bike's transmission running smoothly. Below is a complete, proprietary step-by-step guide for MotoSport.com, including required tools, model-specific considerations, and best practices for a clean, successful oil change.

Tools and Supplies Needed

  • 17mm socket (drain bolt removal)
  • 10mm socket or wrench (oil check bolt/removal, if applicable)
  • Drain pan (to catch old oil)
  • Rubber gloves (to keep hands clean)
  • Rags or shop towels (for cleanup)
  • Funnel (for refilling oil)
  • Ratio Rite cup or measuring cup (precise oil measurement)
  • Replacement oil: Pro Honda HP transmission oil or GN4 10W-40 SF/SG, or equivalent
  • New copper washer (if the old one appears damaged or deformed)

Preparation

  • Warm up the engine for a few minutes to thin the oil; this ensures maximum drainage and flushes debris from the transmission.
  • With the bike off, securely place it on a stand or flat surface.
  • Gather all tools and ensure new oil is ready to go.

Draining the Old Oil

  • Place your drain pan directly underneath the drain bolt, located at the bottom of the engine.
  • Use the 17mm socket to loosen and remove the drain bolt. Be careful: oil may be warm.
  • Remove the transmission oil filler cap to allow air into the system. This helps old oil drain more completely

    .
  • Let the oil drain fully; gently tilt the bike side to side if necessary, to ensure all oil is out

    .
  • Inspect the drain bolt and its copper washer. Replace the washer if it looks deformed or worn

    .

Cleaning and Inspection

  • Clean the drain bolt thoroughly (metal shavings caught on the magnetic tip are normal).
  • Wipe the drain area to remove residual oil. Carefully inspect the threads for damage.
  • If you notice stripped threads, consult a professional before proceeding.

Replacing the Drain Bolt

  • Once the oil stops dripping dramatically, reinstall the drain bolt by hand.
  • Do not overtighten–overtightening can strip the aluminum threads. Snug the bolt securely, but with caution

    .
  • If using a torque wrench, consult your service manual for the correct specification (typically about 13-15 lb-ft).

Adding Fresh Oil

  • Carefully measure 750 ml (0.8 qt) of appropriate transmission oil

    . Maxima MTL is a popular choice, but Honda's GN4 or HP Transmission Oil is also OEM-recommended.
  • Using a funnel, pour about half the oil into the filler opening, pause, then add the rest.
  • Replace the filler cap securely.

Checking Oil Level

  • Start the engine and let it idle for a minute to distribute the oil.
  • Turn off the engine and let the bike sit upright for a minute.
  • Locate the oil check bolt (10mm, usually just right of the clutch cover, identifiable by its copper washer

    ).
  • Remove the oil check bolt:
    • If a slow trickle of oil escapes, the level is correct.
    • If no oil comes out, add small amounts (about 30 ml at a time), checking until oil flows out.
    • Replace and snug the check bolt with its copper washer.

Final Steps and Cleanup

  • Wipe away any oil spills on the case and floor.
  • Safely dispose of the old oil—never pour it down the drain or on the ground. Most auto parts stores accept used oil.
  • Check for leaks around both bolts and under the bike after a short test ride.

Special Notes for the 1998 Honda CR250

  • Model-specific oil capacity: For 1997-1999 CR250 models, the factory “change” capacity is 1.26 liters (approximately 1.32 quarts), but many owners use 750 ml to 850 ml for routine change due to residue left behind

    .
  • Check bolt location: The 10mm check bolt with a copper washer may be mistaken for other bolts nearby—never remove the water drain bolt by mistake

    .
  • Always use a new copper washer if the old one is flattened or missing, as this is crucial for oil-tight sealing.
  • This model uses a transmission/gear oil change—there is no crankcase oil like a four-stroke.
  • The gear oil on a 1998 CR250 lubricates the clutch, gearbox, and primary drive only. For pre-mix, continue to use a 32:1 ratio in your fuel

    .

Conclusion

Changing the transmission oil on your 1998 Honda CR250 is straightforward with the right tools and careful attention to factory instructions. Following these steps helps prevent clutch and gearbox wear and keeps your legendary two-stroke running strong for years. For more expert dirt bike maintenance guides and all your OEM or aftermarket parts, trust MotoSport.com.

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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.