How to Change the Oil in a 2008 KTM 105XC – MotoSport.com Exclusive Guide

Shop parts for a 2008 KTM 105XC Dirt Bike.

Properly changing the oil in your 2008 KTM 105XC is critical to maintaining engine longevity and peak performance. This guide provides step-by-step instructions specific to the 105XC and highlights key model call-outs every owner should know.

Tools & Supplies Needed

  • 13mm socket or wrench
  • Drain pan
  • Funnel
  • New gearbox oil (Motorex recommended, SAE 10W/40 or as specified by KTM)
  • Crush washer (recommended new for every oil change)
  • Torque wrench
  • Contact cleaner or brake cleaner
  • Clean shop towels/paper towels
  • Owner's or Repair Manual (for torque specs and diagrams)
  • Protective gloves (optional for safety)

Preparation

  • Warm up the engine: Start your KTM and let it run for a few minutes. This allows the oil to warm up and drain more efficiently. Be careful: hot oil can cause burns.
  • Secure the bike: Place your 105XC on a level stand so it stays upright and stable during the oil change.

Step-by-Step Instructions

  1. Remove the Filler Cap
    • Locate and unscrew the oil fill cap on top of the right engine case. This step vents the engine and helps oil drain smoothly.
  2. Drain the Old Oil
    • Position your drain pan under the engine.
    • Find the gearbox oil drain plug on the bottom of the engine case. It is typically a 13mm bolt below the shifter lever.
    • Carefully loosen and remove the drain plug using the 13mm socket/wrench. Oil may flow quickly and it will be hot.
    • Allow oil to drain fully. This may take several minutes.
  3. Clean and Inspect the Drain Plug
    • The plug is magneticwipe it clean with a towel and check for excessive metal shavings. A little debris is normal, but large chunks may signal internal wear.
    • Replace the crush washer to prevent future leaks.
  4. Reinstall the Drain Plug
    • Thread in the plug by hand to avoid cross-threading, then tighten it with your torque wrench to 20 Nm (14.8 ft-lbs)–the recommended KTM specification for drain plugs. Overtightening can strip the threads or crush the gasket unevenly.
      Tip: Always use a quality torque wrench for this critical step.
  5. Refill with New Gearbox Oil
    • Using a funnel, pour in 0.45 liters (450cc) of the recommended oil (Motorex, or a high-quality equivalent in the correct viscosity).
    • Pour slowly, and check the level periodically—the 105XC uses a sight glass or dipstick to verify correct fill.
    • High or low oil levels can harm your transmission. Do not overfill. Note: The manual lists the oil fill quantity as 0.45 L for the 2008 KTM 105XC
  6. Replace the Filler Cap
    • Screw the oil fill cap back on securely. KTM recommends gently snugging it a bit with pliers to ensure it doesn't vibrate loose, but do not overtighten.
  7. Check for Leaks and Final Steps
    • Wipe down the engine and run the bike for a minute.
    • Turn off the engine, check underneath for any fresh oil leaks.
    • Double-check oil level—if needed, top off carefully after the bike cools a moment. Never overfill.
  8. Dispose of Old Oil Properly
    • Pour used oil into a sealed container and bring it to a recycling center, auto parts store, or other designated oil recycling location. Do not pour oil into the ground or drains—it's illegal and harmful to the environment.

Special Call-Outs for the 2008 KTM 105XC

  • Oil Quantity: Use 0.45L (450cc) of oil for the gearbox on each oil change for the 105XC model.
  • Recommended Oil: KTM specifies Motorex as their preferred brand and using inferior oils can lead to premature engine wear.
  • Check Oil Level Hot: Always check oil level when the engine is at operating temperature for an accurate reading—checking when cold leads to incorrect readings.
  • Magnetic Drain Plug: Inspect and clean regularly—always replace the crush washer to ensure a good seal.

Maintenance Interval

  • KTM recommends changing the gearbox oil at least every 20 hours of riding or sooner if you ride in harsh conditions or race frequently.

With these steps, your 2008 KTM 105XC will have the clean, high-quality oil it needs to keep running strong. Regular oil changes are simple, cost-effective, and a cornerstone of good dirt bike maintenance.

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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.