How to Change the Oil in a 2021 KTM 350 EXC-F — MotoSport.com Guide

Shop parts for a 2021 KTM 350 EXC-F Dirt Bike.

Regular oil changes ensure the longevity and peak performance of your KTM 350 EXC-F. This how-to guide details the process, highlights essential tools, and explains any model-specific call-outs you should know for the 2021 KTM 350 EXC-F.

Tools & Supplies Needed

  • 17mm socket or wrench (for the crankcase drain plug)
  • 8mm T-handle or socket (for the oil filter cover bolts)
  • Flathead screwdriver (for O-ring removal, as needed)
  • Oil catch pan
  • New oil filter (KTM OEM or quality aftermarket)
  • Crush washer (replace if worn, KTM recommends each oil change)
  • Engine oil (approximately 1.2L, refer to the owner's manual for KTM-recommended 4T oil)
  • Torque wrench (for reassembly to spec; drain plug torque is 15 Nm, oil filter cover bolts are 10 Nm)
  • Clean rags or shop towels
  • Funnel
  • Nitrile gloves (optional, for cleanliness and safety)

Steps to Change the Oil

  1. Warm Up the Engine
    Start and run your KTM for 3-5 minutes to bring the oil to operating temperature. Warm oil drains more thoroughly and carries out contaminants.
  2. Stabilize the Bike
    Turn off the engine. Place the bike on a stand or level ground using the side stand for upright draining.
    Call-out: The EXC-F models are easier to drain upright rather than tilted, ensuring a more complete drain.
  3. Remove the Skid Plate (if equipped)
    Use the appropriate wrench to unbolt and remove any skid plate for easier access to the drain plug and filter.
  4. Position Your Oil Catch Pan under the crankcase drain plug.
  5. Remove the Oil Fill Cap
    Unscrew the fill cap on the right side of the engine to allow the oil to drain faster and more completely.
  6. Drain the Oil
    Use a 13mm or 17mm socket (check your bike) to remove the crankcase drain plug located on the bottom or lower side of the engine. Allow all oil to drain out.
    Inspect the old crush washer—replace if deformed. Inspect the old oil for metallic particles, a sign of early engine trouble.
  7. Remove the Oil Filter
    Use an 8mm socket or T-handle to remove the bolts securing the oil filter cover (lower right side of the engine). Carefully remove the cover. Note the orientation of the old filter and any O-rings. Remove and discard the old filter.
    Call-out: On the EXC-F, lightly fill the oil filter cavity with fresh oil before installing the new filter, per KTM's manual. This helps prevent initial start-up starvation.
  8. Install the New Oil Filter
    Lubricate the new oil filter's O-ring with clean engine oil. Insert the new filter in the same orientation as the old one.
    Wipe the filter cover and install a new O-ring if required. Reinstall the cover and bolts, tightening them with a torque wrench to 10 Nm. Do not overtighten.
  9. Reinstall the Drain Plug
    Once all oil has drained and the drain hole is clean, install a new or inspected crush washer on the plug. Thread the drain plug in by hand to avoid cross-threading, then torque to 15 Nm (11 ft-lb). Wipe any residue.
  10. Add Fresh Oil
    Insert a funnel into the oil filler. Pour in approximately 1.2L of recommended 10W-50 full synthetic 4T oil.
    Note: The manual oil capacity may differ slightly; always fill and then check the sight glass or dipstick to reach the correct level.
  11. Check Oil Level
    With the bike upright (not on the side stand), use the dipstick or sight glass. Add oil in small increments if needed until the level is correct.
  12. Start the Engine
    Run the engine for 30–60 seconds. Shut it off and recheck the oil level. Top up if below the mark—never overfill.
  13. Inspect for Leaks
    Check all around the drain plug and filter cover for any signs of oil seepage.
  14. Reinstall Skid Plate (if removed) and clean up the work area.

Model-Specific Callouts for the 2021 KTM 350 EXC-F

  • Oil Change Interval: KTM recommends every 15 hours of use for hard/aggressive riding. For more casual riding, intervals can be stretched to 20–30 hours, but frequent changes help longevity.
  • Oil Filter Priming: The KTM manual specifies lightly filling the filter cavity with new oil before installing the new filter. This reduces the risk of dry start-up and helps extend engine life.
  • Tightening Torque: The drain plug and filter cover require low torque settings (15 Nm and 10 Nm). Over-tightening can damage threads or crush washers. Always use a torque wrench for accuracy.
  • Crush Washer: KTM recommends replacing this every oil change to prevent leaks.
  • Oil Capacity: It typically takes about 1.2L, including filter replacement, but always verify using the sight glass/dipstick after filling.
  • Oil Spec: 10W-50 full synthetic 4T oil is standard for the EXC-F models. Using the correct spec is vital to ensure clutch and engine integrity.

Final Notes

  • Always log your oil changes and maintenance intervals; this helps with troubleshooting and resale value.
  • Dispose of used oil and filters responsibly at a local recycling center.
  • Keeping a few spare crush washers and filters on hand speeds up routine maintenance.

If you want OEM KTM filters, recommended Motorex 10W-50 Oil, and specialty dirt bike tools, order everything you need from MotoSport.com today.

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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.