How to Change the Oil in a 1987 Honda CR500

Shop parts for a 1987 Honda CR500 Dirt Bike.

Changing the gearbox oil in your 1987 Honda CR500 is an essential maintenance task that ensures your bike’s longevity and performance on the track or trail. This robust step-by-step guide is proprietary to MotoSport.com and tailored specifically for this classic two-stroke beast.

Tools & Supplies Needed

  • Socket wrench set (with appropriate sockets for drain plug and fill plug)
  • Drain pan
  • Funnel
  • Rags or paper towels
  • Measuring cup (with oz/mL markings)
  • Replacement gear oil (Honda Pro HP Transmission Oil or equivalent, or ATF as an alternative)
  • Torque wrench (optional, for properly torquing the drain plug)
  • Goggles and gloves (for cleanliness and safety)

Oil Type and Capacity – 1987 CR500 Specifics

  • Oil Type: Pro Honda HP Transmission Oil is highly recommended for maximum gearbox longevity. Some riders use Automatic Transmission Fluid (ATF) as a budget alternative, but OEM-recommended gear oil offers better protection and cleanliness over time.
    For 1987 models, avoid regular engine oil—stick to transmission-specific oil.
  • Capacity: 23 US fluid ounces (approx. 680 mL) for a regular drain-and-fill. If you have had the cases split or performed a major engine rebuild, fill with 25 US fluid ounces (approx. 740 mL) to account for complete evacuation of old oil.

Step-by-Step Oil Change Instructions

  1. Warm Up the Engine
    Start your CR500 and let it idle for a few minutes. This helps the oil flow freely and suspends contaminants, allowing for a more thorough drain.
  2. Stabilize the Bike
    Secure the bike on a stand, ensuring it is upright and stable. This prevents accidents and allows the oil to drain fully.
  3. Remove the Filler Cap
    Locate the oil filler cap on the right side of the engine. Carefully remove it. This step is critical as it breaks vacuum in the crankcase, enabling the oil to drain more completely.
  4. Drain the Old Oil
    Place your drain pan beneath the gearbox casing’s oil drain bolt, located on the bottom of the engine. Using your socket wrench, carefully remove the drain bolt. Let the oil completely evacuate into the pan—this may take several minutes. Inspect the drain plug for metal shavings or residue, which can indicate internal wear. Clean or replace the crush washer or sealing ring if fitted.
  5. Reinstall the Drain Plug
    When oil has finished draining, reinstall the drain bolt by hand first, then snug it with a socket wrench. If using a torque wrench, set to manufacturer’s recommended torque—do not overtighten. The CR500’s casing is aluminum and fragile; overtightening can strip threads.
  6. Add New Gear Oil
    Using a clean funnel and measuring cup, pour 23 ounces (680 mL) of fresh transmission oil into the fill port. Pour slowly to avoid spills and overfilling. Some prefer to slightly underfill at first, wait a moment, then top off to ensure no air pockets.
  7. Check Oil Level
    Some CR500s feature a level check bolt or sight glass; if yours does, briefly remove the plug after filling. Oil should slightly ooze out when the bike is level, indicating correct fill. Reinstall the check bolt securely.
  8. Replace Filler Cap
    Install and tighten the oil fill cap, being cautious not to strip the plastic or aluminum threads.
  9. Wipe Down and Inspect
    Clean off any spilled oil. Start the bike and let it idle for a minute. Shut it down and check for leaks around the drain plug and fill cap.
  10. Dispose of Old Oil Responsibly
    Pour used oil into a sealable container and drop it off at your local recycling center or auto parts store.

1987 CR500 Call-Outs and Tips

  • This engine is a 2-stroke; oil changes pertain only to the gearbox, not the crankcase.
  • Never overtighten drain bolts—aluminum cases strip easily. Use a torque wrench if possible.
  • For best shifting performance and clutch longevity, use OEM-recommended transmission oil rather than generic engine oil.
  • If you ride hard or in dirty conditions, change oil every 2–4 rides. More frequent changes help keep clutch action crisp and gearbox free of contaminants.
  • Monitor drain plug and oil for signs of excessive metal—this could indicate bearing or gear wear.
  • If you routinely ride in mud, sand, or water, consider checking gear oil even more often for contamination.

Final Notes

  • Capacity: 23 US ounces for routine changes, 25 US ounces after total teardown.
  • Recommended Oil: Pro Honda HP Transmission Oil or equivalent. Avoid multi-viscosity engine oils for this application.

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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.