How to Change the Oil in a 2019 KTM 250SX: A Complete MotoSport.com Guide

Shop parts for a 2019 KTM 250SX Dirt Bike.

Properly maintaining your 2019 KTM 250SX starts with regular oil changes. In this guide, we cover every step, including required tools, best practices, and specific tips for this model to keep your motocross bike running strong.

Tools & Supplies Needed

  • T-handle or socket wrench set (13mm deep socket recommended)
  • Torque wrench
  • Drain pan
  • Funnel
  • Pliers (for oil filter cap)
  • Clean shop towels
  • Fresh engine oil (Consult your owner's manual for viscosity and specification; typically, 10W-50 full synthetic for KTM 2-strokes)
  • Replacement oil filter (OEM 77338005100 or aftermarket equivalent)
  • Replacement crush washer
  • Safety gloves

Preparation

  • Ride the bike briefly or idle it until engine is warm (not hot) to suspend contaminants and ensure easier draining.
  • Place the bike upright on a stable stand, in a well-lit, clean area.
  • Wipe dirt and debris from around the oil fill and drain plugs to prevent contamination.
    Tip: Dirt entering your engine can cause severe internal damage. Take this step seriously.

Step-by-Step Oil Change Process

  1. Remove the Oil Fill Cap
    Unscrew the oil fill cap on the right side of the engine. This allows the oil to drain out faster and more completely by letting air in.
    Be careful when handling a hot motor.
  2. Drain the Engine Oil
    - Position a drain pan under the engine.
    - Use the 13mm socket to remove the drain bolt from the case's bottom. Allow the oil to drain fully.
    - Collect the old oil for proper disposal.
    - Inspect and clean the magnetic drain plug. A small amount of metallic debris is normal.
    - Remove the copper crush washer and set it aside for replacement.
    KTM recommends always replacing the crush washer to ensure a leak-free seal.
  3. Remove and Clean Oil Screens
    - On your 2019 KTM 250SX, locate and remove the oil screen(s), if equipped.
    - Wipe the screens clean of debris before reinstalling.
    This helps prevent blocked oil flow and future engine damage.
  4. Replace the Oil Filter
    - Locate the oil filter cover, remove the bolts (use T-handle/socket wrench), and take out the old filter.
    - Lubricate the seal on the new filter with engine oil.
    - Install the fresh filter (OEM #77338005100 or equivalent).
    - Refit the cover and tighten bolts to the manufacturer's torque specification.
    Not torquing properly can strip the housing or cause leaks. Always check your KTM manual for exact torque values.
  5. Reinstall Drain Plug and Screens
    - Install the new crush washer on the clean drain plug.
    - Reinstall the oil screen(s) and plug, tightening each to spec (usually about 14 ft-lbs or 20 Nm for the drain bolt–always verify your exact model's requirements).
  6. Refill with New Oil
    - Insert a funnel into the oil fill opening.
    - Pour in the recommended quantity of fresh oil (usually about 0.8 liters for a two-stroke KTM 250SX, but always check your manual).
    - Replace the oil fill cap and snug it with pliers as recommended.
  7. Check Oil Level
    - Start the engine and let it idle for a minute.
    - Shut off the engine and let the bike sit upright for a few minutes to allow the oil to settle.
    - Check that the oil level is between the min and max marks on the sight glass.
    - Add or remove oil as needed to reach the proper level.
  8. Inspect for Leaks
    - Run the engine briefly and inspect around the oil filter cover and drain plug for any signs of leakage.
    - Wipe up spills and address any leaks before riding.

2019 KTM 250SX Model-Specific Call-Outs

  • OEM Oil Filter: This model uses KTM part #77338005100.
  • Crush Washer: Always install a new washer on the drain plug to avoid leaks.
  • Torque Specs: Properly torque the drain plug and filter cover bolts. Over-tightening can strip aluminum threads; under-tightening can cause leaks or loosening.
  • Oil Capacity: Double-check your manual for the exact oil quantity. Over-filling or under-filling can harm engine performance.
  • Sight Glass: Use the sight glass with the bike perpendicular to the ground (not on the side stand) to get an accurate reading.
  • Screen Cleaning: The 250SX includes screens on the oil circuit—clean these screens every oil change to remove any gathered particles.
  • Ride Ready: After a successful change, always take a short test ride, then recheck oil levels once the engine has cooled and settled.

Conclusion

Changing the oil on your 2019 KTM 250SX is simple with the right tools, careful attention, and by following the steps outlined above. Regular oil changes help maintain peak power, protect your engine, and ensure more trouble-free rides. Always refer to your KTM owner's manual for any updates or changes to specifications, and trust MotoSport.com for all your OEM and aftermarket parts needs.

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Shop Oil Fillers and Drain Plugs for a 2019 KTM 250SX 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.