How to Change the Coolant in a 1986 Honda CR500: MotoSport.com's Step-by-Step Owner's Guide
Shop parts for a 1986 Honda CR500 Dirt Bike.
The 1986 Honda CR500 is legendary for its raw power and robust performance–but, just like any high-output two-stroke, it demands strict attention to maintenance. Keeping your cooling system in top shape is vital for avoiding overheating and maximizing the longevity of your engine. Our proprietary MotoSport guide delivers clear, model-specific steps for flushing and replacing your CR500's coolant, plus essential notes about this classic dirt bike.
What You Need
- Ethylene glycol-based motorcycle coolant (never mix with tap water or use automotive coolant–stick with motorcycle-specific blends to avoid corrosion in the aluminum system)
- Socket set (for drain bolt and radiator cap removal)
- New water pump crush washer (Honda part 90463-ML7-000 is recommended for a tight seal)
- Catch pan or container for old coolant
- Rags and nitrile gloves
Instructions: Changing Coolant on the 1986 Honda CR500
- Let the engine cool completely. Never open a radiator cap on a hot engine–pressure and scalding coolant can cause serious injury.
- Remove the radiator cap. Locate the radiator cap on the left side of the bike and twist it off slowly to release any residual pressure.
- Position your catch pan. Place it directly below the water pump area (right side of the engine, at the bottom).
- Remove the coolant drain bolt. On the CR500, the drain bolt is at the water pump cover, near the bottom of the clutch-side engine case. Unscrew the bolt and allow the old coolant to fully drain out. Expect this to take several minutes as the coolant trickles out.
- Inspect and replace the crush washer. Always fit a new crush washer onto the drain bolt when reinstalling. This ensures a watertight seal and prevents leaks.
- Reinstall and torque the drain bolt. Tighten the drain bolt securely, but do not overtighten. Clean any spilled coolant from the case.
- Flush if desired. For a full flush, pour a small amount of distilled water into the radiator, reinstall the cap and drain bolt, run the engine briefly, then repeat the draining process until the fluid runs clear. Skip this step if the coolant was recently changed.
- Fill with fresh coolant. Pour motorcycle coolant into the radiator neck slowly, watching for air bubbles as it fills. Fill to the very brim of the filler neck, as close as possible to the top.
- 'Burp' the system. With the radiator cap still off, start the bike and let it idle for a minute. Blip the throttle a few times and gently rock the bike side-to-side to help trapped air escape. Top up coolant if the level drops, then reinstall the cap.
- Check for leaks and test ride. Watch the drain bolt and water pump area for any signs of leaks. After a short ride, let the motor cool and double-check the fluid level, topping off as needed.
MotoSport Owner's Notes: 1986 CR500 Cooling System Tips
- The alert, high-compression two-stroke engine produces significant heat, so never neglect coolant quality or intervals. Overheating can quickly damage the cylinder or head.
- The CR500's aluminum radiator and engine are vulnerable to corrosion–always use the correct ethylene glycol-based motorcycle coolant. Avoid mixing unknown chemicals or using straight water.
- This model uses a radiator overflow tube rather than an expansion reservoir. Fill to the neck, as excess will safely vent off if the engine gets hot.
- Honda's 1986 'flash red' plastics and graphics make preservation important for collectors; coolant leaks can stain engine cases and covers if not wiped up promptly.
- Check the radiator fins for damage or dirt during coolant changes for best airflow and cooling system efficiency.
Properly servicing the cooling system on your classic CR500 preserves both performance and its legendary reputation. For all replacement parts, gaskets, and fluids tailored to your exact model, MotoSport.com is your trusted 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.