How to Change the Oil in a 1980 Kawasaki KX250

Shop parts for a 1980 Kawasaki KX250 Dirt Bike.

Changing the oil in your 1980 Kawasaki KX250 is an essential maintenance task that keeps your dirt bike running strong and maximizes its lifespan. This how-to guide is proprietary to MotoSport.com and walks you through the entire process, call-outs specific to your model, tools needed, and step-by-step instructions to ensure a clean, successful oil change every time.

Tools and Supplies Needed

  • Flathead screwdriver
  • 8mm socket
  • 12mm socket
  • Pliers (for stubborn parts or hose clamps)
  • Drain pan (low profile recommended for dirt bikes)
  • Rags or shop towels
  • Replacement engine oil (refer to owner's manual; typically a high-quality 2-stroke transmission oil, such as Maxima 80W MTL for transmission/gear oil or other manufacturer-recommended product)
  • New crush washer (replace every oil change)
  • Torque wrench (recommended for correct torque on drain bolt)
  • Replacement oil drain plug (recommended: stainless steel magnetic plug for extra engine protection)
  • Measuring cup (Ratio Rite cup for accurate oil fill)
  • Contact cleaner (optional: to clean inside case and around the oil filter)

1980 KX250 Model-Specific Call-Outs

  • The 1980 KX250 is a classic 2-stroke dirt bike, which uses oil in the transmission/gearbox rather than engine crankcase as with four-stroke models.
    Always use 2-stroke transmission/gear oil specified for motocross applications. Engine oil capacity is usually around 750ml, but check your owner's manual for the exact amount.
  • This model uses a standard drain plug on the bottom of the case; replacing with a magnetic stainless steel plug is a worthwhile upgrade to catch metal debris over time and prevent engine damage. Always inspect the magnet and clean thoroughly with every change.
  • Always replace the aluminum crush washer with every oil change to prevent leaks and stripping of the threads.
  • There is no external spin-on oil filter for this model—just a strainer inside the case. Inspect and clean the filter screen if accessible.

Step-by-Step Oil Change Instructions

  1. Warm the engine lightly for a few minutes so oil drains faster, but do not overheat. Let the bike idle and then turn off.
  2. Support the bike upright using a stand or securely stabilize it so it remains upright throughout the service.
  3. Remove oil fill cap with a flathead screwdriver. This allows the system to breathe and drains oil more efficiently.
  4. Place the drain pan under the engine, underneath the drain bolt. Locate the drain bolt at the lowest point of the transmission case.
  5. Remove the drain bolt using a 12mm socket. Allow all old oil to drain completely–tip the bike gently side to side to be sure all oil is evacuated.
  6. Inspect the old oil for excessive metal particles or debris, which could indicate wear.
  7. Remove and discard the old crush washer. Clean the drain bolt and wipe off any magnet debris if using a magnetic drain plug.
  8. Reinstall drain bolt with new crush washer. Start by hand, then tighten with torque wrench to manufacturer's spec (typically around 15 ft-lbs–always confirm specs for 1980 KX250). Do not overtighten to avoid stripping threads.
  9. Inspect or clean the filter screen inside the case if accessible. Consult your service manual for exact location and removal steps–generally this is not needed at every oil change, but check for debris at scheduled intervals.
  10. Use a measuring cup (Ratio Rite or similar) to measure the correct amount of oil. Refer to your owner's manual–typically around 750ml (0.8 quarts) but confirm for your year and modifications.
  11. Add new oil through the fill port. Go slowly to avoid spills.
  12. Replace and snug down the oil fill cap.
  13. Start the engine and let it idle for 2-3 minutes, shifting through gears without riding, to circulate oil.
  14. Turn off engine and let it sit 3-5 minutes. This lets the oil settle for an accurate check.
  15. Check the oil level using the bike's sight glass or dipstick (if fitted). The oil should be at the proper level–typically just below or in the center of the sight glass.
    If low, slowly top off as needed; don't overfill.
  16. Wipe off any spills and inspect for leaks around the drain bolt and fill port.
  17. Dispose of old oil and materials properly–never down the drain or in the yard.

Pro Tips for 1980 Kawasaki KX250 Oil Changes

  • Perform your oil change after every 5-10 hours of hard riding, per manufacturer recommendations and riding conditions.
  • Upgrade to a magnetic oil drain plug to extend the life of your transmission/gearbox by trapping small metal shavings.
  • Regularly inspect the drain plug thread condition on these older engines, as aluminum cases can be stripped by overtightening.
  • Use transmission-specific oil, not regular motor oil or ATF, to optimize gear and clutch performance.
  • Keep a couple of extra crush washers and drain plug gaskets in your toolbox.

If you follow these steps, your vintage 1980 Kawasaki KX250 will stay running strong and ready to hit the trails every time. For high-quality OEM and aftermarket parts, crush washers, drain plugs, and fluids, trust MotoSport.com as your go-to source.

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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.