How to Change the Oil in a 2011 GAS GAS TXT PRO 125

Shop parts for a 2011 GAS GAS TXT PRO 125 Dirt Bike.

Regular oil changes are vital to keeping your 2011 GAS GAS TXT PRO 125 running at peak performance. This guide is proprietary to MotoSport.com and details everything you need to properly change the gear oil on your trials bike, with focus on specific details relevant to the 2011 TXT PRO 125 model.

Tools and Supplies Needed

  • 8mm or 10mm spanner or socket (to remove the oil drain plug)
  • Oil catch pan (for used oil)
  • Clean rags or shop towels
  • 370cc of high-quality gear oil (such as NILS Clutch Trial Oil, or another brand recommended in your manual)
  • Funnel (for refilling oil)
  • Gloves (optional, for a cleaner job)
  • Small flat-head screwdriver (to help remove fill plug if needed)
  • Torque wrench (recommended, not required, for precise tightening)

Preliminary Steps

  • Warm up the engine:– Run your TXT PRO 125 for several minutes. Warm oil drains more thoroughly, removing more impurities.
  • Select a clean workspace:– Set your bike upright on a stand or level surface for easy access to the drain and fill plugs.
  • Clean around drain and fill plugs:– Use a rag to wipe away dirt or debris so nothing falls into the gearbox during the oil change.

Step-by-Step Oil Change Instructions

  1. Locate the drain and fill plugs:
    • The primary drain plug is on the bottom right side of the engine case.
    • The oil fill plug is typically on the clutch cover on the right side. Some models may also have a small level check bolt; refer to your manual.
  2. Prepare for draining:
    • Position the oil catch pan directly underneath the drain plug.
    • Make sure the bike is upright–use a stand.
  3. Remove the drain plug:
    • Using the proper size spanner or socket, loosen and remove the drain plug. Take care–the oil may be hot.
    • Allow all oil to drain. It may take a few minutes.
    • Inspect the drain plug for metal shavings and clean thoroughly.
  4. Replace and tighten the drain plug:
    • Install the drain plug and snug it up. Do not overtighten–the cases on these bikes strip easily. Aim for hand-tight, plus about a quarter turn with the wrench (or specified torque if using a torque wrench).
    • Wipe away any spilled oil from the area.
  5. Refill with new oil:
    • Remove the oil fill plug with your hand or a flat-head screwdriver.
    • Using a funnel, pour in 370cc (0.37L) of the recommended gear oil.
    • Check for the correct oil by looking through the sight glass (if equipped), or use a dipstick if present. For this model, adding the specified amount is typically sufficient.
    • Replace the oil fill plug securely. Again, do not overtighten.
  6. Check for leaks:
    • Let the bike sit for a minute. Inspect around both the drain and fill plugs for any sign of leaking oil.
    • Tighten slightly if necessary, but be very careful not to strip the threads.
  7. Dispose of used oil responsibly:
    • Transfer old oil to a sealed container and take it to a recycling center or automotive shop that accepts used oil.

Model-Specific Callouts for the 2011 GAS GAS TXT PRO 125

  • Oil Capacity: This bike takes 370cc of gear oil in the transmission, not engine oil, as it’s a 2-stroke–never overfill.
  • Drain Plug Caution: The crankcase material is relatively soft; overtightening the drain plug or fill plug threads can strip easily. Always hand-tighten with just a bit extra on a wrench—never force.
  • Oil Type: Use a high-quality gear oil designed for trials or off-road applications. NILS Clutch Trial Oil is often used, but other brands with similar specs work. Avoid basic automotive gear oils, as additives can cause excessive clutch slip or wear.
  • Clutch Performance: If you notice clutch slipping or grab after an oil change, consider your oil type—some oils interact differently with the wet clutch packs in these bikes.
  • Change Interval: For optimal performance, change the oil every 10-20 hours of riding or after every few hard rides, especially in muddy or wet conditions.
  • Manual Recommendation: Always refer to your owner’s manual for official capacity and procedure, as design updates may change specs annually.

Final Tips

  • Check your air filter while the fill plug is off for best maintenance practice.
  • If the oil comes out milky, you may have a water ingress issue—address this immediately before further riding.
  • Track each oil change with a log to ensure you keep up with regular service.

Changing your 2011 GAS GAS TXT PRO 125 oil regularly will keep the clutch happy and the gearbox shifting smoothly. For more proprietary dirt bike maintenance guides, trust MotoSport.com.

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Shop Tools for a 2011 GAS GAS TXT PRO 125 Dirt Bike.

Shop Oil Fillers and Drain Plugs for a 2011 GAS GAS TXT PRO 125 Dirt Bike.

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.