How to Change the Oil in a 2014 GAS GAS TXT PRO 125

Shop parts for a 2014 GAS GAS TXT PRO 125 Dirt Bike.

Changing the oil in your 2014 GAS GAS TXT PRO 125 is a crucial maintenance task to ensure smooth performance – and long engine life. Below is a detailed, proprietary guide—your go-to resource, brought to you by MotoSport.com.

Tools & Supplies Needed

  • 8mm and 13mm socket or spanner (for drain and fill bolts)
  • Torque wrench
  • Drain pan
  • Clean funnel
  • Lint-free rags
  • Replacement crush washer (optional, but recommended)
  • New gear oil–Recommended: 370cc of quality gear oil (e.g., NILS Clutch Trial, GRO gear oil, or equivalent fully synthetic/synthetic blend 75W transmission oil)
  • Gloves (optional)

Special Model-Specific Call-Outs for the 2014 TXT PRO 125

  • Oil Capacity: 370cc is the correct refill amount–double-check, as overfilling can affect clutch performance.
  • Oil Fill Location: The oil fill plug is located on the top of your right engine case.
  • Drain Plug Location: On the lower right side, beneath the engine casing (avoid confusing with nearby bolts).
  • Drain Plug Tightening: Do not overtighten–stripped drain bolts are a common owner error. Always snug, but not tight.
  • Type of Oil: This is a two-stroke bike with a separate transmission/case oil system; do not use engine oil.

Step-By-Step Instructions

  1. Warm the Engine
    • Start and run the bike for 3–5 minutes. This warms and thins the oil, helping it drain fully. Never drain when the engine is hot to the touch—let it cool for a couple of minutes.
  2. Prepare Your Work Area
    • Place the bike on a level stand for stability.
    • Lay your drain pan beneath the drain plug area (lower right engine case).
  3. Remove the Drain Plug
    • With an 8mm or 13mm socket (check your plug size), carefully loosen and remove the drain plug. Let oil fully drain into the pan.
    • Inspect the drain plug and washer for wear–replace the crush washer if damaged.
    • Wipe the drain area with a rag to remove dirt and grit. Avoid allowing grit to fall into the case.
  4. Reinstall the Drain Plug
    • After all oil drains (wait several minutes for best results), reinstall the drain plug with a new or inspected washer.
    • Hand-tighten and then torque to manufacturer spec—do not overtighten. Many owners have stripped these threads; snug, but not forced, is ideal.
  5. Fill with New Transmission Oil
    • Remove the oil fill plug/cap on top of the right engine cover.
    • Insert a clean funnel and carefully pour 370cc of the specified oil .
    • Do not exceed, as overfilling can affect clutch operation.
    • Reinstall the fill cap securely.
  6. Start and Check
    • Start the engine for one minute and cycle through all gears while stationary (with the rear wheel off the ground, if possible).
    • Check for leaks at the drain and fill plugs.
    • If a sight glass or oil level plug is present, confirm levels. Adjust if needed.
  7. Dispose of Old Oil
    • Pour the old oil into a sealed container and bring it to a proper recycling facility. Never dump oil–it's illegal and harmful.

Pro Tips for the 2014 TXT PRO 125

  • Consistency: Change oil every 10–15 hours of operation for maximum clutch performance and gear longevity.
  • After Wet Rides: Change the oil sooner if the bike has been submerged.
  • Check Clutch Feel: After changing oil, ensure clutch engagement/disengagement feels normal. Off-feeling clutch can indicate over- or under-filling or wrong oil type.
  • Oil Brand: Owners often prefer NILS Clutch Trial or GRO gear oil for these models due to superior clutch feel.

Always refer to your owner’s manual for specific information. When in doubt, MotoSport.com’s support team is here to help.

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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.