How to Change the Oil in a 2015 Husqvarna TC85BW (Big Wheel)

Shop parts for a 2015 Husqvarna TC85BW Dirt Bike.

Routine oil changes keep your 2015 Husqvarna TC85BW running smoothly and prevent unwanted engine wear. This step-by-step guide will walk you through the oil change process, highlight all the tools you need, and point out essential model-specific tips MotoSport.com recommends for best results.

Tools and Supplies Needed

  • 8mm and 13mm sockets or wrenches (confirm drain plug size as 13mm, may vary slightly)
  • Flathead screwdriver (if necessary for panel removal)
  • Measuring cup or oil jug (500cc, or about 0.5L of gear oil)
  • Fresh gear oil (quality 2-stroke transmission/gear oil, 75W/80W as per Husqvarna spec)
  • Oil drain pan
  • Clean shop rags
  • Funnel
  • Torque wrench (to set drain plug to spec if available)
  • Replacement drain plug washer (seal ring) (recommended, especially if old one looks worn)
  • Gloves and eye protection (keeps things clean and safe)

Preparation

  • Ensure the bike is on a stable stand with the engine off and cool.
  • Clean the area around the drain plug and filler cap to prevent contamination.

Step-By-Step: Changing the Oil

  1. Locate the Oil Drain Plug
    The drain plug is typically at the bottom of the right engine case. On the 2015 TC85BW, it uses a magnetic tip to catch metal filings and a seal ring to prevent leaks.
  2. Remove the Oil Filler Cap
    The filler cap is at the top of the clutch cover on the right side of the engine. Removing it allows the oil to drain smoothly.
  3. Drain the Old Oil
    Place your oil pan beneath the drain plug. Using the proper size socket or wrench, turn the drain plug counterclockwise to remove. Let all the oil drain completely—this may take several minutes.
    Tip: If your bike has been running, the oil will drain faster and more fully as it's thin and warm, but be careful as hot oil can burn.
  4. Inspect and Clean the Drain Plug
    Wipe off any metal filings captured by the plug's magnet. Inspect the seal ring or washer and replace if it's damaged or flattened to ensure no leaks when reinstalling.
  5. Replace the Drain Plug
    Reinstall the plug with the washer once the oil has fully drained. Tighten it to the manufacturer’s torque spec (do not overtighten) to avoid stripping threads.
    Call-out: Ensure the magnet and seal ring (washer) are intact and seated correctly for the TC85BW as this component is crucial to preventing leaks and capturing gearbox particles
    Clean the sealing surface on the engine. Mount the oil drain plug with the magnet and seal ring and tighten it.
  6. Add New Gear Oil
    Using a funnel, fill the transmission with 500cc (0.5L) of the recommended gear oil. Do not overfill.
    • Pour slowly and pause occasionally to check the level.
    • The correct fill: Oil should reach the bottom edge of the level check screw hole when the bike is upright. Some owners tip the bike upright and wait for oil to just begin to weep out of the level screw hole, ensuring it’s not underfilled nor overfilled (standard for KTM/Husqvarna 85cc platforms) .
    Double-check that you’re using the right oil spec for your year and climate. Husqvarna recommends 75W or 80W gear oil. The 2015 shares the same gear oil system as later TC85 models.
  7. Reinstall the Filler Cap
    Wipe off any spilled oil and securely reinstall the filler cap. Hand-tighten so it's snug, but avoid overtightening.
  8. Check for Leaks and Test
    Start the bike and let it idle for a few minutes. Shut off, check for leaks around the filler and drain plug. If leaks are present, recheck torque and washer condition.

Model-Specific Call-Outs for the 2015 Husqvarna TC85BW

  • Oil Capacity: 500cc (0.5L) is the target fill–all 2013+ TC85s share this capacity.
  • Level Check: Be sure the bike is perfectly upright (not on side stand) when setting the oil level through the oil check screw. Overfilling can lead to leaks, underfilling causes premature clutch wear.
  • Drain Plug Magnet: Always inspect the magnet for debris; large metal pieces may indicate transmission issues.
  • Washer/Seal Ring: Replace with every oil change if possible–the 85's design is prone to weeping leaks with a worn washer.
  • Avoid Over-Tightening: The engine case is aluminum and threads can strip if overtightened.
  • Correct Oil Type: Only use gear oil specified for 2-stroke transmissions; engine oil or car transmission oil is NOT suitable.
  • Environmental Note: Dispose of used oil at a proper facility–do not dump it.

Final Inspection

  • Wipe any drips and double-check all fasteners.
  • Take a short ride, then recheck for leaks and proper shifting/clutch feel.
  • Record the date and hours after the oil change in your maintenance log.

Conclusion

Changing oil in your 2015 Husqvarna TC85BW is a straightforward, essential job that ensures long engine life and smooth performance. MotoSport.com recommends gear oil changes every 5–10 hours of riding or more frequently in harsh conditions. Unsure about any step? Consult your owner’s manual or visit MotoSport.com for OEM Husqvarna parts and expert advice.

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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.