How to Change the Oil in a 1991 Honda CR500

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Keeping your 1991 Honda CR500 running at its best means performing regular oil changes. This robust how-to guide, proprietary to MotoSport.com, walks you through the entire oil change process, highlights specific model call-outs, and lists all the tools you'll need to get the job done right.

Tools and Supplies Needed

  • Socket wrench set
  • Drain pan
  • Measuring cup (marked for fluid ounces)
  • Clean rag
  • Funnel
  • New oil – Pro Honda Gear Oil, or a high-quality equivalent (see below for specific types)
  • Gloves (recommended)

Recommended Oil and Quantities

  • Capacity: 23 US fluid ounces for a regular oil change; 25 ounces if engine was fully disassembled and cleaned
  • Type: Pro Honda Gear Oil is recommended; some riders use ATF (automatic transmission fluid) or high-quality 10W-40 or 20W-50 motor oil, particularly adjusting for seasonal temperatures – 10W-40 for cooler weather, 20W-50 for hot climates (specific to model years around 1991)

Preparation

  • Warm up your CR500 for several minutes. Oil drains best when warm, as impurities suspend in the oil and flow out more easily.
  • Position your bike securely on a stand or flat surface to prevent tipping.

Step-by-Step Oil Change Instructions

  1. Locate the drain bolt
    • On the right side of the engine, find the drain bolt at the bottom of the crankcase.
    • Place your drain pan under this bolt.
  2. Remove oil fill cap
    • Take off the oil fill cap on the right side before you open the drain bolt. This step is crucial: it prevents vacuum pressure, allowing oil to drain fully from the case .
  3. Drain the old oil
    • Carefully loosen and remove the drain plug using a socket wrench.
    • Allow oil to completely drain into the pan. Give it a few minutes for best results.
  4. Reinstall the drain bolt
    • Wipe the drain plug with a clean rag.
    • Inspect the sealing washer; replace if damaged.
    • Thread the bolt by hand to avoid cross-threading, then snug using your wrench. Do not over-tighten; the engine case is aluminum and can strip easily .
  5. Measure and add new oil
    • Using a measuring cup, pour in 23 US ounces of the approved gear oil for a typical oil change (25 ounces if you have fully rebuilt or cleaned the engine).
    • Add the oil through the fill port; a funnel helps prevent spills.
  6. Check the oil level
    • Reinstall the oil fill cap.
    • Start the bike and let it idle for one minute, then turn off.
    • Let the oil settle for a few minutes, then verify level is in spec using sight glass (if equipped) or via the oil level bolt. Some riders let oil seep out of the level check hole — when it starts to slowly drip out, you've reached the correct level .
  7. Clean up
    • Wipe any spilled oil from the case and surrounding area.
    • Dispose of old oil at a certified recycling center.

Special Model Call-Outs for the 1991 Honda CR500

  • The 1991 CR500 is a 2-stroke model. The crankcase oil only lubricates the transmission and clutch, not the top end. It is not shared with the combustion process.
  • Avoid over-tightening the oil drain bolt, as the case is aluminum and can strip easily .
  • Choose oil weight based on riding temperature. Many owners in cooler climates use 10W-40, while 20W-50 is preferred for hot riding conditions. Pro Honda gear oil is optimal, but high-quality ATF (Type F) is an acceptable alternative if OEM gear oil is unavailable .
  • Change interval: Many riders change oil every 2–4 rides or after particularly hard sessions .
  • Oil can get contaminated quickly in 2-stroke gear boxes, especially with heavy clutch use or muddy conditions. Err on the side of more frequent changes.

Conclusion

With the right tools and oil, changing the oil in your 1991 Honda CR500 is straightforward and protects your investment. Following these steps ensures maximum performance and longevity for your bike, whether you’re a trail enthusiast or track racer. For OEM parts, premium oils, and more how-to expertise, trust MotoSport.com as your go-to resource.

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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.