How to Change the Coolant in a 1988 Suzuki RM80: Step-by-Step Guide

Shop parts for a 1988 Suzuki RM80 Dirt Bike.

Changing the coolant on your 1988 Suzuki RM80 is crucial for keeping your 2-stroke engine running cool–especially given the high-revving nature of this iconic minibike. The RM80 is well-loved for its agility and peppy performance, but even the best-maintained bikes need fresh coolant to prevent overheating and internal corrosion. The process is straightforward but knowing a few model-specific tips can make it go smoother.

What You Need

  • Fresh motorcycle coolant (preferably pre-mixed, non-silicate, and safe for aluminum–never use plain water)
  • Catch pan or container
  • 8mm or 10mm wrench or socket (verify bolt size for your specific water pump drain bolt)
  • Phillips or flathead screwdriver
  • Distilled water (for optional system flush)
  • Clean rag
  • Gloves and eye protection

Before You Begin: 1988 RM80 Notes

  • Always ensure the engine is cool before opening the radiator cap to avoid burns.
  • The RM80 cooling system is compact, which makes coolant changes relatively quick.
  • Inspect hoses and radiator fins for any signs of cracks, leaks, or damage while you have access.

Step 1: Remove Seat & Side Panels

Loosen and remove the seat and left side panel using your screwdriver or applicable wrench. This provides better access to the radiator cap and coolant overflow tank.

Step 2: Drain the Old Coolant

  • Place your catch pan under the water pump, on the lower right side of the engine.
  • Locate the drain bolt on the water pump cover. Loosen and remove it with your wrench; let the coolant drain fully.
  • Unscrew the radiator cap to speed draining. This will allow air to enter and coolant to flow out faster.

Step 3: (Optional) Flush with Distilled Water

To remove all old coolant and debris, pour a small amount of distilled water into the radiator. Replace the drain bolt, gently shake the bike side-to-side, then remove the bolt again to let the flush water drain. Repeat if coolant was especially dirty.

Step 4: Replace the Drain Bolt

For best results, install a new sealing washer on the drain bolt. Tighten the bolt securely, but do not overtighten to avoid stripping the threads.

Step 5: Add Fresh Coolant

  • Slowly fill the radiator with fresh coolant up to the base of the filler neck. Avoid spilling on the engine or exhaust.
  • If your RM80 has a small overflow tank, fill it to the upper line as well.

Step 6: Bleed Air from the System

  • With the radiator cap still off, start the engine and let it idle for several minutes.
  • Gently rock the bike side-to-side and lightly rev to help purge air bubbles from the system.
  • If coolant level drops, top it off to the appropriate level and reinstall the radiator cap.

Step 7: Recheck Coolant Level

After a short ride allowing the engine to fully warm up and cool down, re-check the coolant level (both at the radiator and overflow tank) and top up if necessary. This final step is especially important for older RM80s, since trapped air can cause overheating.

Additional Pro Tips

  • Never mix coolant types. Using the wrong coolant can harm 1988 RM80 engine seals & aluminum components.
  • Dispose of old coolant responsibly–never pour it on the ground or down drains.
  • Replace the radiator cap if the seal is cracked or worn, as this can cause pressure loss and boiling.
  • Inspect the water pump cover gasket for signs of leaks and replace if needed whenever you drain the system.

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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.