How to Change the Oil in a 2007 Yamaha YZ85 – MotoSport.com Guide

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Changing the oil in your 2007 Yamaha YZ85 keeps your two-stroke engine running strong and protected. With regular use and aggressive riding, fresh oil is critical to reduce wear on your transmission and internal parts. This step-by-step guide makes it easy for first-timers and experienced riders alike.

Tools and Supplies Needed

  • 10mm wrench or socket – for the drain bolt
  • Oil catch pan – to collect old oil
  • Measuring cup or clear graduated container – to measure the new oil
  • Funnel – for an easy and clean pour
  • Rags or shop towels – for cleanup
  • Gloves – optional, but recommended
  • Correct transmission oil (80W gearbox oil or equivalent)
  • 500ml (17oz) of oil – Required for the 2007 YZ85

Step-By-Step Instructions

  • Prep the Bike
    • Start by thoroughly cleaning the area around the engine and drain bolt to prevent dirt from contaminating the gearbox while changing oil.
      Tip: Dirt or sand entering the engine can cause accelerated wear or even failure.
  • Warm Up the Engine
    • Let the engine idle for 2-3 minutes. Warm oil drains more fully and carries debris away.
    • Shut off the engine before beginning work.
  • Drain the Oil
    • Place your oil catch pan under the engine's drain bolt.
    • On the YZ85, the drain bolt is located next to the brake pedal (right side of the engine). Use your 10mm wrench or socket to remove the bolt carefully.
    • To help the oil drain faster, remove the oil fill cap (top right of the engine near the clutch cover).
    • Allow oil to drain completely. Gently tilt the bike side-to-side while upright to get every last drop.
  • Inspect and Clean
    • Wipe the drain bolt clean, checking for any bits of metal or debris stuck to the magnetic tip (if equipped). Minor slivers are normal; larger chunks could signal issues.
    • Inspect the copper or aluminum crush washer; replace if damaged to prevent leaks.
  • Reinstall the Drain Bolt
    • Thread the drain bolt by hand to avoid cross-threading, then tighten snugly with your wrench. Do not overtighten. The bolt should be secure but not forced.
  • Measure and Add New Oil
    • Check your manual, but the 2007 YZ85 takes 500ml (17oz) of transmission oil.
    • Using your measuring cup, fill a funnel with the correct amount of oil.
    • Slowly pour the oil into the fill port. Avoid dumping it all at once to prevent overflowing.
    • Once full, replace and hand-tighten the oil fill cap.
  • Check for Leaks and Finish Up
    • Clean up any spilled oil.
    • Start the bike and let it run for a minute. Shut off the engine, check around the drain bolt and fill cap for leaks.
    • Dispose of used oil responsibly at a proper recycling facility.

Important Call-Outs for the 2007 Yamaha YZ85

  • Oil Capacity: 500ml (17oz) is the correct fill quantity for this model year.
  • Drain Bolt Location: Right side of the engine, next to the rear brake pedal.
  • Use the Right Oil: Choose a high-quality transmission/gearbox oil formulated for two-stroke motorcycles. Never use engine oils designed for four-stroke engines.
  • Regular Changes: For racing or aggressive riding, change oil after every 5-10 hours of use or after each ride in harsh conditions.
  • Crush Washer: Replace if damaged or crushed flat to maintain a proper seal.

Final Tips

  • Keep a maintenance log for oil changes and parts replacements – this helps with resale and diagnosis.
  • Clean hands after the job even when wearing gloves; clutch oil can be irritating to the skin.
  • If you see milky oil (from water contamination), immediately diagnose for bad seals or gaskets.

Changing oil on your 2007 Yamaha YZ85 is an easy DIY that keeps your bike performing its best. Always refer to your owner’s manual for specific torque specs and additional recommendations. For quality oils, parts, and all your dirt bike needs, trust MotoSport.com — supporting riders worldwide.

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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.