How to Change the Oil in a 1997 Yamaha RT100

Shop parts for a 1997 Yamaha RT100 Dirt Bike.

Keeping your 1997 Yamaha RT100 running smoothly means regular maintenance — and one of the most crucial tasks is a proper transmission oil change. The RT100 uses a two-stroke engine, so you’ll be changing the transmission oil, not crankcase oil. This guide provides model-specific call-outs, a list of required tools, and robust step-by-step instructions so you can confidently tackle the job yourself. Proudly brought to you by MotoSport.com.

Tools and Supplies Needed

  • Socket wrench set (for drain bolt)
  • Drain pan
  • Clean rags
  • Torque wrench (for precise tightening of the drain bolt)
  • Measuring cup (for oil)
  • Replacement transmission oil – Use a high-quality 10W-30 or 10W-40 motorcycle-specific oil, or synthetic oil equivalent (see owner’s manual)
  • Funnel
  • Gloves (to keep hands clean and safe)

Before You Start: Special Notes for the 1997 Yamaha RT100

  • The RT100’s engine oil is for the transmission and clutch area only — it does NOT lubricate the combustion end of the engine.
  • Never overfill. Use the dipstick or level marks to check proper oil level.
  • The manufacturer recommends checking the oil with the bike upright — a tilt will result in inaccurate readings.
  • Drain bolt tightening torque for this model is 20 Nm.

Step-by-Step: Changing the Oil

  1. Warm up the Engine
    Run the bike for several minutes. Oil drains more thoroughly when warm, carrying away more contaminants.
    Tip: Do not overheat. Just a few minutes of idle or light riding is sufficient.
  2. Turn off the Engine and Secure the Bike
    Shut off the RT100 and place it on a stand or flat, stable surface. Ensure the bike remains upright and level. This ensures both accurate oil draining and measurement when finished.
  3. Remove the Dipstick
    Unscrew the oil dipstick from the filler hole. Set it aside somewhere clean.
  4. Place the Drain Pan
    Position an oil drain pan directly underneath the drain bolt at the bottom of the transmission case.
  5. Remove Drain Bolt and Drain Old Oil
    Using your socket wrench, carefully loosen and remove the drain bolt.
    Allow all old oil to fully drain. This may take a few minutes.
    Caution: The engine and oil may still be hot.
  6. Clean and Reinstall the Drain Bolt
    Inspect the drain bolt and its gasket for debris or damage. Wipe it clean. Replace the gasket if necessary. Reinstall the drain bolt and use a torque wrench to tighten it to 20 Nm as specified for the RT100.
  7. Add Fresh Oil
    With the funnel, pour the correct amount of recommended oil into the filler hole.
    Do not guess – refer to your owner’s manual for the exact oil volume (typically between 650-750 ml for this model, but confirm since overfilling or underfilling can cause damage).
  8. Check the Oil Level
    Wait a few minutes for the oil to settle. Insert, but do not screw in, the dipstick and check that the oil is between the minimum and maximum level marks.
    Add a small amount if the oil is low. Remove excess if high.
  9. Replace the Dipstick and Clean Up
    Screw the dipstick fully back into place. Wipe any spilled oil off the engine and floor. Properly dispose of the used oil at an authorized recycling facility.

Post-Change Checklist

  • Double-check drain bolt tightness to manufacturer spec.
  • Verify oil level sits within recommended range after engine has idled briefly and cooled.
  • Look for any leaks around the drain bolt or filler cap after running the engine for a minute.

RT100 Transmission Oil Change Call-Outs

  • Always keep the RT100 upright when measuring oil level for accuracy — even a slight tilt yields unreliable readings.
  • The transmission oil functions as both transmission and clutch lubricant; regular changes are critical for smooth gear shifts and clutch longevity.
  • The RT100 has a modest oil volume; overfilling can cause excessive pressure and leaks, underfilling risks gear and clutch damage.

When to Change the Oil

  • At least every 10-15 riding hours or after any wet, muddy ride.
  • Always change after break-in, or when oil looks dark, gritty or smells burnt.

Keeping up with oil changes on the 1997 Yamaha RT100 is one of the simplest and most important maintenance jobs you can do. For parts, oil, and expert advice, MotoSport.com has you covered for every ride.

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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.