How to Change the Oil in a 1987 Kawasaki KX250: A MotoSport.com Guide
Shop parts for a 1987 Kawasaki KX250 Dirt Bike.
The 1987 Kawasaki KX250 is a legendary two-stroke dirt bike that's known for its performance and reliability. Regular oil changes are critical to keep your engine running smoothly and to extend its lifespan on the track or trail. This guide will walk you step-by-step through the oil change process, provide specific call-outs for your 1987 model, and ensure your maintenance routine keeps your KX250 operating at its best.
Tools and Supplies Needed
- Flathead screwdriver
- 8mm and 12mm sockets with ratchet
- Pliers (optional, for stubborn bolts)
- New engine oil (Rec: Castrol Power 1 5W40 full synthetic, or equivalent high quality 2-stroke gearbox oil)
- Oil drain pan
- Shop rags or paper towels
- Replacement crush washer (highly recommended)
- New oil filter if applicable (Note: Many 2-stroke KX250s do not have a replaceable oil filter, check your manual)
- Torque wrench
- Contact cleaner (optional, for cleaning oil filter cavity or drain area)
Preparation
- Start the engine briefly and let it idle for a few minutes to help warm the oil. Warm oil drains more thoroughly and suspends contaminants better.
- Turn off the engine and locate your drain plug (bottom of the crankcase).
- Put your KX250 on a stand or secure it upright for easy and safe access.
Step-by-Step Oil Change Instructions
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Remove the Oil Fill Cap
- With your flathead screwdriver, remove the oil fill cap to help the crankcase vent and oil drain more freely.
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Drain the Oil
- Position a drain pan beneath the crankcase.
- Remove the oil drain bolt using a 12mm socket.
- Allow all oil to fully drain; this may take several minutes. Tip the bike slightly side to side to help drain as much old oil as possible.
- Inspect the crush washer on the drain bolt for signs of deformation or damage. Replace it if necessary to prevent leaks.
- Clean the drain bolt and reinstall it by hand, then tighten to the specified torque (15 foot-pounds).
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Oil Filter Service (If Equipped)
- Most 1987 KX250 models do not have a replaceable oil filter, but if yours has an aftermarket kit or conversion, remove the 8mm bolts on the cover, pull the cap, and remove the filter.
- Clean the cavity with contact cleaner if desired.
- Install a new filter (rubber grommet facing in), replace the cover and torque 8mm bolts to 9 foot-pounds.
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Fill with New Oil
- Check your manual or side case for the correct oil type and fill quantity.
- For the 1987 KX250, add approximately 0.75–0.85 quarts (700–800 ml) of high-quality two-stroke transmission oil.
- Slowly pour the oil through the fill port. Proceed carefully to avoid overfilling.
- Reinstall and snug the oil fill cap.
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Verify Oil Level
- Start the bike and let it idle for 3–5 minutes to circulate oil in the transmission and clutch (not the top end – this is a two-stroke).
- Shut off engine, wait another few minutes, then check the oil level using the sight glass on the right crankcase cover (just below the rear brake lever).
- Oil should be in the middle to upper portion of the sight glass. Add oil if needed to reach correct level.
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Clean Up and Final Checks
- Check for leaks around the drain plug and fill cap. Correct as necessary.
- Wipe up any spilled oil.
- Dispose of used oil responsibly at a recycling facility.
Key Model-Specific Call-Outs for the 1987 Kawasaki KX250
- This model uses a two-stroke premix for top end lubrication, so the crankcase oil only services the clutch and transmission. Changing the oil regularly is crucial for preserving smooth shifting and proper clutch function.
- No external oil filter is standard, so take extra care to drain debris and consider more frequent oil changes compared to modern four-strokes.
- Crush washer replacement is very important to prevent chronic leaks on older bikes with well-used drain plug areas.
- If you see silvery debris in your old oil, inspect your clutch for excessive wear, as this is often a sign the clutch plates are nearing their service limit.
- Always use motorcycle-specific two-stroke gearbox oil–automotive engine oils lack the correct friction modifiers and may damage clutch plates or cause poor shifting.
- Do not overfill. Too much oil may cause “frothing” and poor gearbox lubrication.
Conclusion
Regular, correct oil changes are essential for the longevity and performance of your 1987 Kawasaki KX250. Stick to quality oil, replace your crush washer, and check for any unusual signs of wear every time you service your bike. For more parts, oils, and tools, trust MotoSport.com – your authority 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.