How to Change the Oil in a 2018 Sherco 125SE-R

Shop parts for a 2018 Sherco 125SE-R Dirt Bike.

If you want to keep your 2018 Sherco 125SE-R running smoothly, regular oil changes are essential for maintaining engine health and performance. This guide—proprietary to MotoSport.com—shows you step-by-step how to change the oil specifically for the 2018 Sherco 125SE-R, including special points every owner should know.

Tools and Supplies Needed

  • 17mm socket (for the main drain bolt)
  • 8mm and 4mm Allen wrenches (for select covers and bolts)
  • Oil drain pan
  • Shop towels or rags
  • Torque wrench (recommended for reinstalling drain bolts)
  • Fresh gearbox oil (SAE 10W40; capacity 750 ml as per the standard SE-R range–see owner’s manual or workshop manual for confirmation)
  • Replacement crush washer (for the drain bolt)
  • Funnel
  • Disposable gloves
  • Parts cleaner or brake cleaner

Preparation

  • Start the bike and let it idle for a few minutes to warm the oil. Warm oil drains more completely and carries away more contaminants.
  • Turn off the engine and secure the bike using a stand to ensure it is upright and stable.

Step-by-Step Oil Change Process

  1. Locate the Oil Drain Plug
    • On the 2018 Sherco 125SE-R, the main oil drain bolt is a magnetic drain bolt located at the bottom of the engine case. You will need a 17mm socket to remove it.
  2. Remove the Drain Bolt and Drain the Oil
    • Place your oil drain pan directly beneath the drain plug.
    • Use the 17mm socket to remove the drain bolt. Allow all the oil to drain from the case.
    • Watch for the crush washer. Inspect it for damage – always replace if it appears crushed, cracked, or excessively worn.
    • Check the magnetic tip of the bolt for metal particles. Wipe it clean using a shop towel.
  3. Clean and Reseat the Drain Plug
    • Once oil has fully drained, clean the area around the drain and the bolt threads.
    • Install a new crush washer if needed.
    • Hand-tighten the drain plug, then use a torque wrench to tighten it to the manufacturer’s specification (refer to your owner’s manual or workshop manual for exact specs).
  4. Clean the Pre-Screens
    • The 2018 Sherco 125SE-R has plastic pre-screens which should be cleaned during an oil change. Remove them according to your manual—usually requiring a 4mm Allen wrench.
    • Use brake cleaner or a parts cleaner to remove debris. Let them dry before reinstalling. Be cautious not to damage any O-rings or the screen itself.
  5. Refill With Fresh Oil
    • Locate the oil fill cap, typically on the right side of the engine case.
    • Using a funnel, add 750 ml of SAE 10W40 engine oil (always confirm in your specific manual as small production variances may require different amounts).
    • If your bike has an oil level window, fill slowly and check periodically to avoid overfilling.
  6. Start the Engine and Check for Leaks
    • Start the bike and allow it to idle for a minute. Watch the area around the drain bolt for leaks.
    • Stop the engine and wait a minute for oil to settle, then check the oil level again through the sight glass or dipstick (if equipped); top up as needed.

Model-Specific Call-Outs for 2018 Sherco 125SE-R Owners

  • The main drain bolt is magnetic and should be cleaned each oil change to remove any metal fragments that indicate engine wear.
  • First oil change: Sherco recommends the first (break-in) oil change at just 5 hours of use. After this, regular changes are suggested every 6,000 km (about 4,000 miles), but frequent oil changes are highly recommended for off-road and race conditions.
  • The 125SE-R gearbox is separate from the two-stroke premix system. Only change the gearbox oil as directed; do not add oil to the fuel as part of this procedure—refer to your premix guidelines for correct fuel/oil ratios.
  • Use only high-quality, non-friction-modifier oils. Avoid automotive oils with friction-reducing additives, as these can harm clutch performance.
  • Be sure to record your maintenance in a log for warranty and long-term value.

FAQs

  • How often should oil be changed? The official recommendation is every 6,000 km or 4,000 miles, but most off-road riders change it much more frequently, often every 10–20 hours depending on riding conditions and intensity.
  • Can I use synthetic oil? Check your manual, but high-quality synthetic two-stroke transmission oil is often used for improved protection and shifting feel.

Conclusion

Changing the oil on your 2018 Sherco 125SE-R is a straightforward job that protects your engine and clutch, ensuring long life and performance. Always consult your owner’s manual and use the correct oil for the best results. For more parts, tools, and maintenance tips, trust MotoSport.com—your ultimate source for everything dirt bike.

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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.