How to Change the Oil in a 2006 GAS GAS EC 300

Shop parts for a 2006 GAS GAS EC 300 Dirt Bike.

Changing the transmission oil in your 2006 GAS GAS EC 300 is an essential part of routine maintenance, ensuring smooth shifting and longevity of the engine’s moving parts. While two-stroke engines like the EC 300 don’t require oil changes in the engine itself, they do need periodic transmission oil changes. The steps outlined here are proprietary to MotoSport.com and tailored to the 2006 model based on owner and technician practices.

Tools and Supplies Needed

  • Oil drain pan
  • 6mm Allen wrench or Allen socket (for drain and fill plugs)
  • Socket wrench set (for skid plate removal, if equipped)
  • Paper towels or shop rags
  • Brake cleaner (optional, for cleaning parts)
  • Generic funnel (small)
  • Fresh transmission oil (typically 75W or 80W gear oil, check owner’s manual for exact spec)
  • Measuring cup (to pour precisely 900cc of oil)
  • Torque wrench (recommended for reinstalling plugs to factory specs)

Model-Specific Call-Outs

  • The oil fill hole is small and awkwardly placed; a small funnel or syringe is highly recommended for refill to avoid spills.
    (Also, some owners opt to lay the bike over for easier fill access.)
  • If you have an aftermarket or factory skid plate, it will almost certainly need to be removed to access the oil drain plug on the bottom of the case.
    (Some plates have a hole for the plug, but not always.)
  • The oil drain plug is magnetic aluminum—be careful not to round off the head and clean off any metallic debris you find stuck to the magnet before reinstalling

    .
  • This bike does not have an oil filter, so regular changes are important to keep oil fresh

    .
  • Do not overfill: The correct oil capacity is 900cc.

Step-by-Step Guide to Changing Oil

  1. Preparation
    • Warm the engine up for a minute or two to make the oil thinner and easier to drain (ride it around the parking lot or let it idle briefly).
    • Shut the engine off and let it cool until it’s safe to touch.
    • Set the bike upright on a stand or lift.
    • Assemble all your tools and supplies within arm’s reach.
  2. Remove the Skid Plate (if installed)
    • Using the appropriate socket/Allen wrench, remove the bolts holding the skid plate to expose the bottom of the engine.
    • Set the bolts and plate aside.
  3. Drain the Old Oil
    • Place your drain pan directly under the drain plug, located on the bottom of the engine case (look for a 6mm Allen plug).
    • Using the 6mm Allen wrench (socket style works best), carefully loosen and remove the drain plug.
    • Allow all oil to drain completely. Tip: Slightly tilting the bike side-to-side can ensure a better drain

      .
    • Inspect and clean the magnetic end of the plug. Remove any metal shavings with a shop towel or brake cleaner. These are normal but should be monitored for excessive buildup.
  4. Reinstall the Drain Plug
    • Once oil stops dripping, thread the drain plug back in by hand to ensure you don’t cross-thread.
    • Tighten snugly with the Allen wrench or, if available, use a torque wrench set to the spec from your owner’s manual (typically 8-12 ft-lbs for similar Gas Gas models, but confirm for your bike).
    • Wipe away any oil residue on the case to help quickly spot any leaks after refill.
  5. Fill Crankcase With Fresh Oil
    • Locate the oil fill plug (on the side of the engine case). It’s small and awkwardly placed, so be patient.
    • Remove the fill plug with a 6mm Allen wrench.
    • Insert your funnel (a short, small one works best).
    • Measure out 900cc of fresh gear oil using your measuring cup.
    • Slowly pour oil into the funnel, taking care not to overfill or spill.
    • Reinstall and snug down the fill plug when complete.
  6. Check for Leaks – Final Steps
    • Double-check both the drain and fill plugs for tightness.
    • Start the bike and let it idle for a couple of minutes.
    • Shut the bike down and inspect the drain and fill plugs for any signs of leakage. If leaking, re-torque as needed.
    • Reinstall your skid plate if removed, securing it properly.
    • Safely dispose of old oil at a recycling center.

Troubleshooting and Tips

  • If you overfill, remove the drain plug briefly to let a bit of oil out, or use a large syringe through the fill port.
  • Skipping oil changes increases clutch and gear wear—set a reminder every 15-20 hours or after every few rides.
  • Excessive metal debris on the drain plug can indicate the need for clutch inspection or possible transmission gear wear.
  • Always use quality oil, as two-stroke transmission oil lubricates both the clutch and gears.

Changing the transmission oil in your 2006 GAS GAS EC 300 is quick, inexpensive, and straightforward with the proper tools and a little patience. Keeping fresh oil in your dirt bike is the simplest way to maximize performance and reliability—MotoSport.com is proud to help keep your ride running strong.

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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.