How to Change the Oil in a 1992 Honda CT70

Shop parts for a 1992 Honda CT70 Dirt Bike.

Changing the oil in your 1992 Honda CT70 ensures smooth operation and extends the life of your classic mini trail bike. Here’s a step-by-step, proprietary guide brought to you by MotoSport.com for CT70 owners, including essential tools, detailed steps, and model-specific tips.

Tools and Supplies Needed

  • 17mm wrench or socket (for the drain plug)
  • Oil catch pan
  • Clean rags or paper towels
  • Gloves (recommended to protect your hands from hot oil)
  • Funnel (for clean oil fill)
  • New engine oil (approx. 0.7 liters or 1.5 US pints, consult owner’s manual for oil grade — typically 10W-40 non-synthetic for the CT70)
  • Replacement drain plug washer or O-ring (if needed)

Step-by-Step Oil Change Process

  1. Warm Up the Engine

    Start your CT70 and let it idle for about 3-5 minutes. Warm oil flows better and carries away contaminants.

  2. Secure Your Bike

    Turn off the engine. Prop the bike upright on its main stand or use a bike stand to keep it steady and level.

  3. Locate and Remove the Drain Plug

    Place the oil catch pan under the drain plug, located on the bottom of the right engine crankcase. Use a 17mm wrench to carefully loosen and remove the drain bolt. Watch for hot oil and let it drain completely into the pan. Tip: Keep the drain plug and washer in a safe spot; clean them for later reinstallation.

  4. Remove the Oil Filler Cap

    While oil is draining, unscrew the oil filler cap/dipstick from the right side of the engine. This helps oil flow out quicker and more completely.

  5. Optional: Operate the Kick Starter

    For a thorough drain, gently operate the kick starter a few times (with the ignition off) to help expel any residual oil from the engine.

  6. Inspect and Replace the Washer or O-ring

    Check the drain plug’s washer or O-ring for wear. Replace with a new one if it appears damaged or flattened. This is important to prevent leaks when you reinstall the drain plug.

  7. Reinstall Drain Plug

    Once the oil has fully drained, reinstall the cleaned drain plug and washer. Tighten it snugly with the 17mm wrench, but do not overtighten to avoid stripping the threads or damaging the case.

  8. Add New Engine Oil

    Insert a funnel into the oil filler opening and add approximately 0.7 liters (1.5 US pints) of your chosen engine oil. Pour slowly to avoid overfilling.

  9. Check the Oil Level

    Let the oil settle for a minute. Insert (but do not screw in) the dipstick, then remove it and check the oil level. It should sit between the upper and lower markings. Add more oil if needed, taking care not to exceed the top mark. Proper oil level is important on the CT70 – too much or too little can affect performance and longevity.

  10. Reinstall Oil Filler Cap

    Once satisfied with the oil level, securely reinstall the oil filler cap/dipstick.

  11. Start and Inspect

    Start the engine and let it idle for a minute. Check for oil leaks around the drain plug and filler cap. Shut off the engine, wait a few minutes, and recheck the oil level, topping off if necessary.

Specific Call-Outs for 1992 Honda CT70 Owners

  • Honda CT70 models, including the 1992, hold about 0.7 liters/1.5 US pints of oil. Do not overfill;– always use the dipstick for verification. When checking, insert the dipstick without screwing it in for accuracy.
  • Inspect the O-ring on the drain plug — using a worn O-ring may lead to leaks. Replacement is inexpensive and strongly recommended if needed.
  • Use only the owner’s manual recommended oil type and viscosity for optimal clutch and engine performance (typically 10W-40 for most climates).
  • If the CT70 is equipped with an aftermarket exhaust or modifications, ensure drain plug access isn’t blocked, or be prepared to loosen the exhaust for easier access.
  • For bikes that run extra hard or are ridden in dusty or muddy conditions, change the oil more often than the usual recommended interval.

How Often Should You Change the Oil?

  • Initial break-in oil change: after first 100 miles (if engine is new or rebuilt).
  • Routine oil change: every 600 miles or at the start of each riding season.

Routine oil changes are the best preventative maintenance you can do for your Honda CT70. For more guides like this, visit MotoSport.com and keep your vintage mini trail running for decades more.

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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.