How to Change the Coolant in a 1982 Suzuki RM80: Complete Guide

Shop parts for a 1982 Suzuki RM80 Dirt Bike.

Maintaining a healthy cooling system is vital for the longevity and performance of your classic 1982 Suzuki RM80. Regular coolant changes prevent overheating and corrosion two threats that can significantly shorten the life of your two-stroke engine. Follow this MotoSport proprietary step-by-step guide to change your RM80's coolant with confidence and keep your mini motocrosser running at its best.

What You Need

  • Fresh coolant (preferably motorcycle-specific, non-silicate; pre-mixed if possible)
  • Drain pan
  • Basic metric hand tools
  • Funnel
  • Distilled water (if doing a full flush)
  • Clean shop rags or towels
  • Protective gloves

Before You Begin: Noteworthy Model Details

The 1982 Suzuki RM80 uses a liquid-cooled two-stroke engine with a simple radiator – no fan, electric temp sensors, or complicated plumbing. However, the aluminum construction is vulnerable to corrosion from poor coolant choice or infrequent changing. This makes coolant maintenance especially important to protect the water pump, radiator, and internal passages from scale or damage. Note: The RM80 does not have a coolant reservoir; only the radiator needs to be serviced.

Step 1: Allow the Bike to Cool

Never remove the radiator cap when hot. Let the RM80 cool completely to avoid injury and prevent coolant geysers.

Step 2: Remove the Seat and Side Panels (if necessary)

For easier access to the radiator cap and drain bolt, remove the seat and left-side panel using your basic tools. This step may not be required if you have direct access.

Step 3: Place the Drain Pan

Position a pan under the water pump cover, which is on the lower left side of the engine. The drain bolt is typically at the bottom of the pump housing.

Step 4: Open the Radiator Cap

Slowly loosen the radiator cap to relieve system pressure. This helps the system drain thoroughly.

Step 5: Remove the Coolant Drain Bolt

Locate and carefully remove the coolant drain bolt at the water pump cover. Old coolant will flow out – guide it into the drain pan. Tilt the bike gently from side to side to ensure complete drainage.

Step 6: Flush the System (If Needed)

If the coolant appears dirty or if you're switching types (for example, from a water-based formula to a glycol blend), flush the system by re-installing the bolt, filling the radiator with distilled water, and repeating the draining process.

Step 7: Reinstall the Drain Bolt

Wipe the bolt and sealing area clean. Inspect the drain bolt washer and replace it if deformed. Reinstall and tighten the bolt securely – do not overtighten.

Step 8: Add New Coolant

Using a funnel, pour new coolant into the radiator up to the base of the filler neck. Allow time for any trapped air to escape. Do not overfill.

Step 9: Bleed Air from the System

With the radiator cap off, start the engine and let it run at idle for a few minutes. Gently rock the bike or lightly blip the throttle periodically to help purge air bubbles. Watch as the coolant level drops – add more as needed to keep it at the top of the neck.

Step 10: Reinstall the Radiator Cap and Inspect

Once bubbling stops and the level holds steady, securely reinstall the radiator cap. Check for leaks around the drain bolt and water pump cover. Wipe up any spillage.

Step 11: Final Checks

  • Start the engine and let it fully warm up, then shut off and allow to cool.
  • Remove the cap once cool and verify coolant level. Top off if necessary.
  • Reinstall all panels and seat.

Disposal

Never pour old coolant down a drain or on the ground. Collect the used fluid and deliver it to a certified recycling or disposal center in your area.

Extra Care Tips for Your 1982 RM80

  • Check coolant every few rides, especially if you run the bike hard or in hot conditions.
  • Always use coolant safe for aluminum motorcycle engines to prevent internal corrosion.
  • Avoid tap water in your coolant mix; only use distilled water if you must create your own blend.
  • Inspect the water pump seals for signs of leakage – any weepage should be addressed promptly to prevent more expensive repairs.
  • If you have recently replaced the water pump or rebuilt the engine, do a coolant change soon after break-in, as residual debris may contaminate new fluid.

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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.