How to change the coolant in a 1998 Honda CR80 Big Wheel Dirt Bike

How to Change the Coolant in a 1998 Honda CR80 Big Wheel

Regularly changing the coolant in your 1998 Honda CR80RB Big Wheel is essential to keep the liquid-cooled engine performing at its peak and avoid overheating on the track or trail. This robust guide, powered by MotoSport, walks you through the full proprietary process and highlights details unique to the CR80RB (also known as the Big Wheel).

Key Steps for Coolant Replacement

• Ensure the bike is cool. Never open the radiator cap on a hot engine to avoid dangerous steam burns. Allow the bike to sufficiently cool before beginning.
• Locate the radiator and drain bolt. Find the radiator cap on the top of the left-side radiator. The coolant drain bolt is positioned at the bottom of the water pump cover (lower right side of the engine) and typically uses a copper or aluminum crush washer to seal.
• Prepare your workspace. Place a suitable drain pan beneath the water pump area to catch old coolant. Have rags and water handy in case of spills.
• Remove the radiator cap. Slowly unscrew the cap to relieve pressure. This will allow coolant to drain more freely.
  
• Loosen and remove the drain bolt. Use a socket or wrench to carefully loosen the drain bolt on the water pump cover. Be ready–coolant will drain quickly. Let it fully empty.
• Optional: Flush the system. For a comprehensive service, pour distilled water through the radiator filler neck with the drain bolt out to rinse any residual coolant or debris. Repeat until the water runs clear.
• Inspect the overflow tank. The CR80RB features a small overflow reservoir below the radiator.
  
  • Check that the overflow tank is also empty–remove the connecting hose if needed to drain.
    
  • Flush with water if you see debris or residue inside.
    
• Inspect hoses and clamps. Squeeze radiator hoses gently–they should feel pliable, not brittle. Check for cracks, leaks, and firm hose clamp connections.
• Reinstall the drain bolt. Install a fresh crush washer if available for a perfect seal. Tighten the bolt to the manufacturer torque spec (if using a torque wrench, consult your owner's manual).
• Fill with new coolant. Honda recommends a high-quality ethylene glycol-based coolant or their premix. The CR80 Big Wheel holds approximately 370 ml (0.39 US quarts) for a coolant change.
  
  • Fill slowly through the radiator neck to prevent air bubbles.
    
  • Gently rock the bike or squeeze hoses to help evacuate trapped air.
    
  • Fill up to the bottom of the filler neck.
    
• Bleed air from the system. Leave the radiator cap off. Start the engine and idle for 1–2 minutes, watching the coolant level. Top off as needed, then shut off and let cool.
• Replace the radiator cap. Secure the cap. Double-check all fittings for leaks.

Special Notes for the 1998 Honda CR80RB Big Wheel

• The CR80RB shares its core engine platform with standard CR80s but features larger wheels and minor frame variations. The cooling and filling process is identical to the standard CR80, but always double-check hose routing and overflow tank placement, as these can differ slightly on the Big Wheel model.
• Due to the compact engine design, access to the drain bolt and some radiator hoses can be tight. Using a slim socket and extension may help in confined spaces.
• For best cooling performance and system longevity, always use distilled water mixed with proper coolant. Tap water can introduce minerals that degrade engine parts.

Maintenance Tips

• Change your coolant every 40–50 engine hours or yearly, whichever comes first for active riders.
• Always inspect for leaks or signs of overheating after servicing. Replace compromised hoses and clamps promptly.
• Keep the radiator fins clean and straight for ideal heat transfer. Bent fins can be gently realigned with a small screwdriver.

Your 1998 Honda CR80RB Big Wheel depends on healthy coolant to keep you riding hard and safe all season. For OE parts, gasket kits, and performance upgrades, trust MotoSport to supply everything you need for expert DIY maintenance.

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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.