How to Change the Coolant in a 1980 Yamaha YZ250: Step-by-Step Guide
Shop parts for a 1980 Yamaha YZ250 Dirt Bike.
Regular coolant changes are essential for maintaining the legendary performance of your 1980 Yamaha YZ250. This classic two-stroke is air-cooled on many earlier models, but the 1980 YZ250 introduced a new liquid-cooled engine – a significant upgrade from previous years. Keeping the cooling system in top shape ensures reliable rides and maximum longevity for your MX machine. Here's the proprietary MotoSport.com guide to get the job done right.
Tools & Supplies You'll Need
- Fresh motorcycle coolant (avoid automotive coolants unless specified for motorcycles)
- Drain pan
- Funnel
- Socket wrench set
- Distilled water (for flushing, if desired)
- Phillips screwdriver
- Clean rag
Preparation
- Ensure the engine is completely cool before starting to avoid burns from hot coolant or engine parts.
- Place the bike on a stable stand in a well-ventilated area.
Changing the Coolant
-
Remove the Radiator Cap
Carefully remove the radiator cap to release pressure from the system. -
Find the Coolant Drain Bolt
Look for the drain bolt at the base of the water pump cover on the right side of the engine. Place the drain pan directly underneath. -
Drain the Old Coolant
Remove the drain bolt. Allow the old coolant to completely drain into your pan.
Tip: Tilting the bike gently side-to-side can help clear trapped coolant. -
Flush the System (Optional, Recommended for Older Bikes)
Replace the drain bolt. Pour distilled water into the radiator. Replace the cap and briefly run the engine (30–60 seconds, don't let it overheat). Shut it off, let cool, then drain again. Repeat until water runs clear. -
Install the Drain Bolt
Make sure the drain bolt and sealing washer are clean and in good condition. Reinstall and tighten the bolt securely, but do not overtighten. -
Add New Coolant
Using a funnel, slowly fill the radiator with the recommended premixed coolant until it reaches the base of the filler neck.
Periodically squeeze the radiator hoses to help release trapped air. -
Bleed Air from the System
With the cap off, start the engine and let it idle for 1–2 minutes. You may see bubbles rise as air escapes. Keep an eye on the coolant level and top up as it drops. -
Final Checks
Once bubbling stops and the coolant remains steady at the filler neck, shut off the engine and let it cool. Top off coolant as needed, then securely reinstall the radiator cap.
Inspect for leaks from the radiator, hoses, or drain plug.
Important Notes for the 1980 YZ250 Owner
- The 1980 model introduced Yamaha's first liquid-cooled YZ250. It is crucial only to fill with coolant suitable for aluminum components to avoid corrosion.
- Always use distilled water for flushing, never tap water – minerals in tap water can damage your radiator over time.
- This older model does not have an overflow reservoir; proper bleeding of the system is key.
- Regular inspection of radiator hoses and aluminum core for corrosion or cracks is recommended.
Ride On
Maintaining your 1980 Yamaha YZ250's cooling system protects your classic motocross investment. Change your coolant yearly or after several long rides, especially if you ride in muddy or hot conditions. For OEM and performance cooling components, MotoSport.com keeps you running cool year after year.
Related Shopping Categories
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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.