How to Change the Oil in a 2015 Yamaha YZ85 – MotoSport.com Guide

Shop parts for a 2015 Yamaha YZ85 Dirt Bike.

Routine oil changes are critical to keeping your 2015 Yamaha YZ85 performing at its best. This comprehensive guide will walk you through every step, from tools required to specific model tips, ensuring your YZ85's engine remains protected through every ride.

Tools & Supplies Needed

  • 10 mm socket or wrench (for drain bolt)
  • Measuring cup or graduated container (at least 500 ml capacity)
  • Fresh transmission/gear oil (500 ml, MotoSport recommends high-quality brands such as Motul Transoil)
  • Oil catch pan
  • Clean rags or shop towels
  • Funnel (optional, for refill)
  • Gloves (recommended for cleanliness)
  • Torque wrench (to re-tighten drain bolt to specification)

Preparation Steps

  • Warm up the engine by idling the bike for 2-3 minutes. Warm oil drains more easily and carries contaminants out with it.
  • Turn the bike off, and ensure it's on a stable, level surface using a bike stand.
  • Clean the area around the drain bolt and fill plug to prevent dirt from entering the engine.

Step-by-Step Oil Change Instructions

  • Locate the Drain Bolt:
    • Find the 10 mm drain bolt on the bottom or lower side of the engine case, often near the brake lever (important for 2015 YZ85).
  • Place the Oil Catch Pan:
    • Slide your oil pan underneath to catch old oil as it drains.
  • Remove the Drain Bolt:
    • Use the 10 mm wrench to loosen, then unscrew the drain bolt by hand.
    • Allow the oil to drain completely; this can take several minutes. Tip the bike slightly side to side if necessary to get out all old oil .
  • Remove the Fill Plug:
    • Open the transmission fill plug/cap at the top, which helps the oil drain more quickly by venting air .
  • Inspect & Clean Drain Bolt:
    • Wipe down the bolt and check for any metal shavings (these can indicate internal wear).
    • Replace the washer or O-ring if damaged to ensure a good seal.
  • Reinstall the Drain Bolt:
    • Thread the drain bolt back into place by hand to avoid stripping.
    • Torque it to 10 Nm (Newton-meters) using your torque wrench .
  • Refill with Fresh Oil:
    • Use a funnel to pour in 500 ml (500 cc) of transmission/gear oil; this amount is specific for the 2015 YZ85 .
    • MotoSport recommends high-quality oils like Motul Transoil for best performance .
  • Replace the Fill Plug:
    • Screw the plug back on snugly; do not overtighten.
  • Clean Up & Check:
    • Wipe any spilled oil from the engine and floor.
    • Start the engine, let it run for a minute, then check for leaks at both bolts.
    • After the first ride post-oil change, check for oil leaks again and top off if necessary.

Model-Specific Call-Outs for 2015 Yamaha YZ85

  • Only use non-motor/gear oil in the trans—never engine oil or auto gear oil.
  • Always check for signs of coolant or water in the drained oil. Milky color may indicate a leaky seal needing repair.
  • Torque specification for the drain bolt is 10 Nm. Using the correct torque prevents stripping the case.
  • 500 ml is the correct fill capacity. Overfilling can cause foaming and clutch issues; underfilling leads to accelerated wear.
  • Warm up the engine before draining. Cold oil can leave debris behind.
  • Clean filler and drain areas before opening. Dirt can cause internal engine damage if introduced during an oil change.

Pro Tips from MotoSport.com

  • Keep a maintenance log to track your oil changes.
  • Use gloves to avoid contact with used oil, which can be harmful.
  • Dispose of oil responsibly at a recycling center or auto parts store—never in the trash or down the drain.
  • Always confirm oil level after starting the bike—top up as necessary.

Conclusion

Changing the oil on your 2015 Yamaha YZ85 is a quick and straightforward process that protects your engine and maximizes clutch performance. With proper preparation, the right tools, and adherence to manufacturer instructions for your specific model, oil changes can be accomplished confidently at home. For more OEM parts, tools, and performance products, visit MotoSport.com.

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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.