How to Change the Coolant in a 1989 Honda CR500: Step-by-Step MotoSport Guide

Shop parts for a 1989 Honda CR500 Dirt Bike.

Maintaining the cooling system on your 1989 Honda CR500 is crucial for reliable performance and engine longevity. This iconic two-stroke powerhouse runs hot under aggressive riding, making a properly serviced coolant system essential. Below is a proprietary, comprehensive guide from MotoSport on changing the coolant on your CR500. Be sure to follow each step closely, as older motorcycles require extra diligence to keep them at peak performance.

What You'll Need

  • Ethylene glycol-based coolant (never use coolant with silicates or intended for automotive aluminum radiators only; always confirm compatibility)
  • Distilled water (for pre-mixing if your coolant is concentrate)
  • 10mm wrench or socket (for drain bolt)
  • Fresh crush washer for drain bolt (Honda #90463-ML7-000)
  • Catching pan or bucket for old coolant
  • Funnel
  • Protective gloves & eyewear
  • Rags for cleanup

Step 1: Preparation & Safety

  • Ensure the bike is completely coolnever work on a hot cooling system.
  • Position your CR500 on a stable stand, with ample space to work alongside the left radiator and engine cases.
  • Remove your radiator cap slowly to relieve any pressure.

Step 2: Draining the Old Coolant

  • Locate the water pump drain bolt on the engine case (lower right side near the coolant hose). Prepare your catch pan beneath it.
  • Remove the drain bolt with a 10mm wrench. Allow coolant to fully drainopening the radiator cap will accelerate flow.
  • If equipped, also disconnect the small hose running to the expansion tank (if fitted) and let it drain out any remaining fluid.
  • Inspect the old coolant for contamination (oil, excessive debris)if present, further inspection or service may be required.

Step 3: Flushing the System (If Needed)

  • For a thorough flush, pour distilled water through the radiator fill neck, then briefly re-install the drain bolt (finger tight) and run the engine for 30 seconds before repeating the drain process. Your rinse water should come out clear before moving on.

Step 4: Replace the Crush Washer & Reinstall Drain Bolt

  • Always use a new crush washer on the drain bolt to prevent leaks.
  • Tighten the drain bolt to factory spec (typically hand-tight plus another quarter-turn; avoid over-torquing on older cases).

Step 5: Adding New Coolant

  • If using concentrate, dilute coolant with distilled water to a 50/50 mix before pouring in.
  • Slowly fill the radiator at the filler neck until the coolant reaches the very bottom of the neck.
  • Check the expansion tank/reservoir (if fitted) and fill between min and max lines.

Step 6: Bleeding Air from the Cooling System

  • With the radiator cap off, start the engine and let it idle for several minutes.
  • Blip the throttle a few times and lightly rock the CR500 side to sidethis helps trapped air escape.
  • As the coolant level drops, top it off to the neck and watch for steady circulation (no bubbles).
  • Once you see movement and no more air, shut off the engine and top off again if needed.
  • Reinstall the radiator cap securely.

Step 7: Post-Service Check

  • Let the bike fully cool to ambient temperature, then recheck coolant level at the radiator neck and in the expansion tank.
  • Add more coolant if the level has dropped.
  • Wipe down any spilled coolantantifreeze is slippery and toxic to pets and wildlife.
  • Properly dispose of old coolant at an authorized recycling center.

Special Notes for Owners of the 1989 Honda CR500

  • This bike is legendary for its raw power & big-bore two-stroke engine—heat management is critical, especially during high-RPM riding.
  • Never use tap water with your coolant—only distilled water to avoid mineral deposits in the radiators and cylinder head.
  • If you ride in hot or demanding conditions, inspect your hoses and radiator fins for signs of wear or impact damage each coolant service.
  • CR500s from this era do not have a thermostat—warm-up takes longer, and the open cooling flow means air pockets are more likely if you fill too quickly. Take your time bleeding the system.
  • Consider periodic inspection of the water pump seal and impeller if you spot persistent leaks or signs of milky coolant, as these are known stress points on older two-strokes.

Changing the coolant on a vintage machine like the 1989 Honda CR500 is straightforward with routine care and the right parts. Maximize reliability and keep your ride running strong by following this MotoSport guide.

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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.