How to Change the Oil in a 2010 KTM 105SX

Shop parts for a 2010 KTM 105SX Dirt Bike.

Changing the oil on your 2010 KTM 105SX is vital for maintaining optimal transmission performance and ensuring a long service life. The process is straightforward and can be accomplished with basic tools and attention to detail. This comprehensive guide is exclusive to MotoSport.com and tailors steps and cautions specifically to the KTM 105SX 2010 two-stroke model.

Tools and Materials Needed

  • 8mm socket or T-handle
  • Torque wrench (capable of 20 Nm/14.8 ft-lb)
  • Oil drain pan
  • Funnel
  • Clean rags or paper towels
  • Magnetic drain plug with a new crush washer
  • Transmission oil as recommended by KTM (0.8L, use 10W-40 or as per Owner's Manual)
  • Pliers (for oil fill cap snugging)
  • Parts cleaner or brake cleaner (to clean plug and any debris)
  • Gloves (for protection from hot oil)

Preparation

  • Let the engine warm up for 2–3 minutes. Warm oil flows more freely and will drain more thoroughly.
  • Set the bike securely on a level surface or bike stand.
  • Gather all your tools and oil before starting.
  • Place an oil catch pan underneath the crankcase drain plug.

Step-by-Step Oil Change Procedure

  • Remove the Oil Fill Cap:
    • Loosen the fill cap on the right side of the engine. Removing this cap before draining will allow air in and help oil flow out more efficiently.
      Tip: Set the cap somewhere clean to avoid dirt contamination.
  • Drain the Old Oil:
    • Use your 8mm socket or T-handle to carefully loosen the drain plug located underneath the engine (left side near the shift lever).
    • Allow the oil to drain completely into the pan. Exercise caution if the engine is hot—the oil will drain quickly and can be hot enough to burn.
      Be careful not to drop the drain plug into the pan for easier retrieval and to keep it clean.
  • Inspect and Clean the Drain Plug:
    • The plug is usually magnetic and may have some metal particles—clean thoroughly with a rag and parts cleaner.
    • Check the condition of the crush washer and replace it with a new one every oil change to ensure a proper seal and prevent leaks.
  • Reinstall the Drain Plug:
    • Screw in the cleaned drain plug by hand, being careful not to cross-thread.
    • Use your torque wrench to tighten it to 20 Newton-meters (14.8 ft-lb) as specified by KTM for this model.
      Do not overtighten—the crankcase threads are delicate.
  • Add New Transmission Oil:
    • Insert a clean funnel into the oil fill hole.
    • Pour in 0.8 liters (just under 1 quart) of recommended 10W-40 transmission oil. Pour slowly to avoid overfilling.
    • # If your oil level check bolt is present (varies by production batch), you can remove it with an 8mm wrench and add oil until it weeps out the hole, then reinstall. Otherwise, carefully measure the oil volume.
  • Reinstall the Fill Cap:
    • Once full, reinstall the fill cap and snug it using pliers, as KTM advises, to prevent it from coming loose unexpectedly.
  • Check for Leaks and Proper Oil Level:
    • Wipe down the area around the drain and fill plugs.
    • Start the engine for 1–2 minutes, then inspect for leaks.
    • Let the bike sit for a minute and then check the oil level through the fill cap’s sight hole or check bolt (if equipped).

Model-Specific Call-Outs for the 2010 KTM 105SX

  • This is a two-stroke engine. The crankcase/transmission oil is completely separate from premix oil used in the fuel—it solely lubricates the transmission. Do not use engine oil or any oil not rated for two-stroke transmissions.
  • Oil Capacity: 0.8L (0.85 quarts). Overfilling can cause excess pressure or foaming inside the transmission. Under-filling can cause gear wear or seizure.
  • The magnetic drain plug is designed to attract any ferrous particles from gear wear; minor metallic “fuzz” is normal, but chunks, copper, or excessive debris should be investigated further.
  • Crush washer replacement is mandatory every change to avoid seepage.
  • Recommended interval for oil changes is every 5–10 hours of riding or after any muddy, wet, or race conditions (see Owner’s Manual for service interval confirmation).
  • Do not overtighten any plug—thread damage can be expensive and time-consuming to repair.

Final Checks and Tips

  • Dispose of old oil responsibly at a recycling center or automotive store that accepts used oil.
  • Inspect the area again after your next ride for leaks to ensure you have a proper seal on the drain and fill caps.
  • If you’re unsure about proper oil or have trouble removing stubborn bolts, consult your KTM dealer or a qualified mechanic before proceeding.

Changing the oil in your 2010 KTM 105SX is a straightforward task that, when done regularly, keeps your dirt bike running strong and shifting reliably. For more maintenance tips, trusted parts, and high-performance products, always check 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.