How to Change the Oil in a 2010 Yamaha YZ85: Step-by-Step Guide

Shop parts for a 2010 Yamaha YZ85 Dirt Bike.

Keeping the oil fresh on your 2010 Yamaha YZ85 is a critical part of regular maintenance that ensures your bike performs at its best and remains reliable. In this in-depth guide, proprietary to MotoSport.com, we’ll cover all the tools you’ll need, detailed steps, and model-specific notes for a smooth and effective oil change. Experienced or just starting out, you’ll finish with confidence and a cleaner-running dirt bike.

Tools and Supplies Needed

  • 10mm socket or spanner (for the oil drain bolt)
  • Oil drain pan (to catch old oil)
  • Funnel (for refilling oil)
  • Rags or paper towels
  • Disposable gloves (recommended for cleanliness)
  • Fresh transmission oil (500 mL/cc’s) – consult your owner’s manual for recommended type
  • Parts cleaner or degreaser (to clean the drain bolt)

Preparation

  • Clean your bike first. Dirt near the filler or drain bolts can get inside your engine – always work from a clean surface for best results and longer engine life. A quick rinse and dry is all you need before starting.
  • Warm up the engine. Allow the engine to run for a couple of minutes. This helps suspend contaminants and allows the oil to drain efficiently.
  • Secure the bike on a stand. A center stand or triangle stand ensures the bike remains upright, stable, and safe during maintenance.

Step-by-Step Instructions

  1. Locate the Drain Bolt
    • The drain bolt on the 2010 YZ85 is located underneath the engine case, typically right next to your brake lever.
    • Prepare your oil pan below the bolt before loosening it so you don’t spill oil onto the ground.
  2. Remove the Oil Drain Bolt
    • Use the 10mm socket or spanner to loosen the bolt. Remove it by hand toward the end to prevent dropping it into the oil pan.
    • Allow the oil to flow freely. Tilting the bike slightly towards the drain side (but not so far that it tips over) helps remove the last bit of old oil.
  3. Inspect and Clean the Drain Bolt
    • Check the drain bolt for metal shavings or debris – a small amount is normal, but chunks or an excessive amount may indicate a problem.
    • Clean the bolt thoroughly with a rag or parts cleaner.
    • If your drain bolt uses a crush washer, inspect it and replace if it’s damaged.
  4. Reinstall the Drain Bolt
    • Once oil has fully drained and the bolt is clean, reinstall the drain bolt and hand-tighten, then finish tightening with the 10mm wrench or socket. Do not overtighten; snug is sufficient.
  5. Remove the Oil Fill Cap
    • The fill cap on the YZ85 is located on the engine’s right side. Remove it to allow access for refilling and ensure air flow as you pour.
  6. Add Fresh Oil
    • Using a small funnel, pour exactly 500 mL of the manufacturer-recommended transmission oil into the fill port. Do not overfill – the 2010 YZ85 is quite sensitive to oil levels.
    • Double-check your owner’s manual for oil specifications and capacity in case of any previous modifications.
  7. Secure the Fill Cap
    • Wipe around the fill opening to ensure it’s clean. Reinstall the fill cap securely.
  8. Check for Leaks
    • Start the bike and let it idle for a minute to circulate the fresh oil. Inspect the drain bolt and fill area for leaks. If you spot any, turn off the bike and tighten the bolts gently as needed.
  9. Dispose of Old Oil
    • Pour the old oil from your drain pan into a sealed container and bring it to your local recycling center or auto parts shop for proper disposal. Never pour it onto the ground or into the trash.

Model-Specific Tips: 2010 Yamaha YZ85

  • Oil capacity is 500 mL (500 cc’s) – using too much or too little will affect performance and longevity.
  • Only use transmission oil specifically for 2-stroke gearboxes. Automotive oils do not provide the correct protection or clutch performance.
  • Always change oil after muddy or wet riding. Water contamination is a risk, especially after creek crossings or rain races.
  • Inspect oil for milky appearance – this can indicate water intrusion which may require additional investigation.
  • On the YZ85, always ensure the drain bolt is tightened, but never overtighten. Stripping the small threads on the case is a common (& expensive) mistake.
  • Best accessibility tips: If you’re new to the bike, kneel on the throttle side to spot both the fill and drain ports easily.

Final Advice

  • Consistently changing the oil at recommended intervals (every 5-10 hours of use or more frequently for racing/riding in harsh conditions) is the cheapest insurance for your YZ85’s performance and reliability.
  • Keep track of oil change dates and hour meter for easy maintenance planning.
  • If you have any doubts, always refer to your owner’s manual or consult a Yamaha dealer.

MotoSport.com has all the OEM and high-performance oils, tools, and replacement parts you need for your 2010 Yamaha YZ85. Ride safe and happy wrenching.

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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.