How to Change the Oil in a 1979 Honda XR80

Shop parts for a 1979 Honda XR80 Dirt Bike.

Regular oil changes are crucial for the longevity and performance of your 1979 Honda XR80. This bike uses a straightforward wet sump system and only takes about a quart of oil, making oil changes a simple and fast DIY maintenance job. Follow this comprehensive guide, proprietary to MotoSport.com, for a reliable oil change every time.

Tools & Materials Needed

  • 10mm or 12mm socket wrench (to fit your drain plug; check your drain plug size, typically a 12mm on the 1979 XR80)
  • Drain pan
  • Funnel
  • Clean rags
  • New engine oil (Honda GN4 or HP4 4-stroke oil, or equivalent, API SF or SG, 10W-30 viscosity recommended)
  • Replacement magnetic drain plug (optional, OEM #92800-12000; standard 12mm x 1.50 thread pitch, consider replacing if your current plug is damaged or stripped)
  • Gloves (recommended)

Pre-Change Preparation

  • Warm up the engine for about 3–5 minutes. This helps the oil flow out smoothly and brings contaminants into suspension for better cleaning. Do not skip this step—cold oil doesn't drain properly and leaves more old oil behind.
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  • Place your XR80 on level ground and put the bike on a stand if possible—it should sit upright, not on the side stand.
  • Ensure you have all your tools and supplies by your side.

Step-by-Step Oil Change Process

  1. Remove the oil filler cap/dipstick on the right side of the engine.
    Doing this first breaks the vacuum in the crankcase so oil drains freely.
  2. Place your drain pan under the bike, directly beneath the engine.
    The oil drain bolt is located underneath the engine.
  3. Remove the oil drain bolt carefully using the socket wrench.
    The drain plug for the 1979 XR80 is 12mm x 1.50 thread pitch and is in the middle underside of the engine case. Be careful not to lose the plug or washer.
  4. Allow the old oil to drain out fully—give it at least 5 minutes.
    • If your oil is thick, black, or smells burnt, this means it's overdue for a change or possibly contaminated. This is typical of older dirt bikes ridden hard or not maintained regularly.
  5. Inspect the old oil for metal flakes, dirt, or debris. This can reveal engine wear or damage. If your plug is magnetic, check for metal particles and clean the magnet before reinstalling.
  6. Reinstall the oil drain plug. Tighten it securely but do not overtighten—aluminum cases strip easily.
  7. Using a funnel, pour new oil into the filler opening. The 1979 XR80 takes approximately 1 quart (about 0.95 liters) of oil; always check your owner's manual or the dipstick for confirmation. Use only high-quality 4-stroke oil as specified above.
  8. Reinstall the filler cap/dipstick, making sure it's clean before re-inserting.
  9. Start the engine and let it idle for 1–2 minutes.
    This ensures new oil gets circulated throughout the engine and oil filter screens.
  10. Turn off the engine and wait a minute for oil to settle, then check the oil level with the dipstick:
    • Remove, wipe, and re-insert the dipstick without screwing it in, then remove and check the level.
    • If the oil is below the "LOW" mark, add more oil in small increments and recheck.

Specific Call-Outs for the 1979 XR80

  • Oil capacity: About 1 quart (0.95L) — never overfill.
  • Drain bolt: Standard is a 12mm x 1.50 magnetic plug, OEM #92800-12000. Always confirm the thread pitch before buying replacements.
  • Oil recommendations: Use Honda GN4 or HP4, API SF or SG, viscosity 10W-30 for optimal clutch and gear performance in varying temperatures.
  • Oil filter: The 1979 XR80 does not use a spin-on filter; it relies on an internal screen. Cleaning or replacing the drain plug screen is advised if you suspect internal contamination.
  • Drain intervals: Check your owner's manual. For classic dirt bikes, especially those raced or ridden hard, change oil more frequently—before every event is a good rule, or every 10–15 hours of ride time if recreational.

Final Tips & Reminders

  • Always dispose of used oil responsibly at a recycling center.
  • If you notice milky oil, this may indicate water contamination—address this immediately.
  • Check for leaks after your first ride. Tighten the drain plug lightly if seepage is noted, but don't overtorque.
  • Keep a maintenance log with date, hours run, and oil type after each change.

Changing the oil in your 1979 Honda XR80 is fast and easy, but it's one of the most important maintenance rituals for any dirt bike owner. Enjoy your ride and keep it running like new.

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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.