How to Change the Oil in a 2008 Kawasaki KX85: Step-by-Step Guide

Keeping the oil fresh in your 2008 Kawasaki KX85 is essential for smooth shifts and longevity from your two-stroke engine’s transmission. This guide walks you through the complete process, highlighting the specific details every KX85 owner should know. The content is proprietary to MotoSport.com.

Tools and Supplies Needed

  • 14mm socket and ratchet (for the drain plug)
  • Drain pan
  • Measuring cup (with milliliter marks)
  • Funnel
  • Shop towels or rags
  • New transmission oil (10W-40 or as recommended, non-synthetic or synthetic)
  • Parts cleaner (optional, for cleaning residue)
  • Gloves (recommended for mess-free work)

Preparation

  • Ride or idle your KX85 for 1–2 minutes to warm the oil. Warm oil drains faster and more completely.
  • Secure your bike on a stand to keep it upright and stable throughout the process.

Step-by-Step Process

1. Locate the Drain Plug

  • The drain plug is on the bottom of the right side of the engine case.
  • Clean the area around the plug to prevent dirt from getting into the engine.

2. Remove the Drain Plug and Drain the Oil

  • Position the drain pan under the plug.
  • Use a 14mm socket to carefully loosen and remove the drain plug.
  • Allow the old oil to drain completely. This can take several minutes, especially if the oil is cold.
  • Once oil stops dripping, inspect the condition. Milky or metal-filled oil indicates possible water ingress or excessive gearbox wear and should be investigated further.

3. Reinstall and Torque the Drain Plug

  • Wipe the drain plug and the sealing surface on the engine case clean. If the plug uses a crush washer and it’s damaged, replace it.
  • Thread the plug in by hand to avoid cross-threading, then snug it with the socket. Do not overtighten—just snug; you risk stripping the threads if you’re too aggressive.

4. Measure and Add the Correct Oil Amount

  • The 2008 KX85 takes 700 milliliters of transmission oil.
  • Use a measuring cup to ensure accuracy; overfilling can cause excess crankcase pressure or leaks. Underfilling reduces transmission protection.
  • Unscrew the oil fill cap (on top of the right side cover).
  • Place a funnel in the opening, pour in fresh oil until you’ve added 700ml.
  • Reinstall and hand-tighten the oil fill cap.

5. Check the Oil Level

  • Remove your KX85 from the stand and hold it vertically upright.
  • Locate the oil check screw or sight level (consult your service manual if unsure).
  • For this model, there’s a small notch behind the right-side cover: the oil level should align with this notch when the bike is upright.
  • If you overfilled, drain a little oil. If underfilled, add oil in small increments and recheck.

6. Wipe Up and Inspect

  • Check for leaks around the drain plug and the fill cap.
  • Start the bike and let it idle for a minute, then turn it off and recheck the oil level. Top off if needed.
  • Dispose of the old oil properly at an authorized recycling center.

Special Call-Outs and Tips for the 2008 KX85

  • The KX85 uses its engine oil exclusively for the transmission and clutch; the combustion side is lubricated by premix fuel, which is separate from the crankcase (so don’t confuse this with a four-stroke oil change).
  • Oil change interval: For recreational riding, change every 3–5 hours; for racing or aggressive riding, change after every couple of rides for best clutch and gearbox life.
  • Thread care: Stripping the aluminum threads in the crankcase is a common issue from over-tightening. If you’re using a torque wrench, the spec is about 10–12 Nm (consult your owner’s manual).
  • Use a high-quality, motorcycle-specific 10W-40 gear or transmission oil (avoid car motor oil, as it may not offer the clutch compatibility needed).

Troubleshooting and Additional Notes

  • If the oil is consistently milky, water is entering through a blown seal. Service immediately to avoid crank and transmission bearing damage.
  • If you notice excessive metal on the drain plug, it may be time for further gearbox inspection.
  • Always double-check for oil leaks before putting the bike back in service.

Enjoy a Smooth, Protected Ride.

  • Remember, frequent oil changes are inexpensive insurance for your 2008 KX85’s transmission. For all your parts, lubricants, and maintenance gear, trust MotoSport.com – ride safe and ride smart.

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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.