How to Change the Coolant in a 1981 Suzuki RM60

Shop parts for a 1981 Suzuki RM60 Dirt Bike.

The 1981 Suzuki RM60 is a legendary small-displacement motocross bike, prized for its light weight and two-stroke punch. Regular cooling system maintenance is crucial for keeping your RM60 running strong, as overheating can quickly cause severe engine damage—especially on classic bikes. Here is a step-by-step guide to changing the coolant, as well as tips specific to the maintenance quirks of the RM60.

Things You Will Need

  • Fresh coolant suitable for aluminum engines
  • Basic hand tools (socket/wrench set, screwdrivers)
  • Catch pan for old coolant
  • Gloves and protective eyewear
  • Funnel and distilled water (optional for flushing)
  • Clean rags

Steps to Change the Coolant

  1. Cool Engine Completely
    Ensure the bike is on level ground and the engine is completely cool before beginning. Removing the radiator cap when hot can cause burns.
  2. Remove Skid Plate & Plastics (if necessary)
    To reach the drain bolt and radiators, you may need to remove the side panels or skid plate.
  3. Open the Radiator Cap
    Slowly loosen and remove the radiator cap to relieve pressure.
  4. Drain Old Coolant
    Place a drain pan underneath, then locate and remove the coolant drain bolt on the water pump housing or lower section of the engine case. Allow all coolant to fully drain. Some models may have a separate bleed screw at the bottom of the radiator–check your RM60 for this feature.
  5. Flush if Desired
    For dirty or neglected systems, pour distilled water into the radiator, reinstall the cap and drain bolt, run the engine briefly, let it cool, and repeat the drain process.
  6. Inspect Components
    Check radiator hoses for cracks, stiffness, or bulges. Make sure hose clamps are tight. Inspect the radiator fins for bending or mud–straighten gently if needed and clean carefully⁠.
  7. Refill with Fresh Coolant
    Insert the drain bolt and ensure it's snug, but do not overtighten–strip threads can be a common issue on older cases. Use a funnel to add coolant until it's just below the filler neck.
  8. Bleed Air from the System
    Gently rock the bike side-to-side and squeeze the hoses to help air bubbles escape. If the RM60 has a bleed screw on the cylinder or radiator, open it briefly until coolant flows steadily, then close.
  9. Run and Heat Cycle the Engine
    Start the bike and let it idle until up to full operating temperature. Watch the coolant level to ensure there are no leaks and the level doesn't drop drastically. Shut off the engine, let it fully cool, then recheck the coolant level. Top off if needed.
  10. Reinstall Plastics and Final Check
    Reinstall any panels or guards, wipe up any spills, and properly dispose of the old coolant. Double-check for leaks after your first ride.

Important RM60-Specific Notes

  • The 1981 RM60 uses an air-vented radiator design with no fan or overflow reservoir. It is critical to get all the air out of the system and always use the correct pre-mixed coolant strength.
  • Due to the bike's age, radiator fins and hoses may be especially susceptible to damage—replace as needed to prevent overheating.
  • The magnesium engine case is especially prone to corrosion if exposed to plain water or improper coolant types. Always use aluminum-compatible coolant and never run straight water except when flushing.

Pro Tips for Vintage RM60 Owners

  • Flush and replace coolant each season, or after any muddy rides or overheating events.
  • Inspect drain bolt and radiator cap seals for brittleness and replace if cracked. Leaks here are a common issue on older bikes.
  • If unsure about the condition of radiator hoses or clamps, consider replacing them with new parts to avoid sudden failures when riding.

Related Shopping Categories

Shop Radiators for a 1981 Suzuki RM60 Dirt Bike.

Shop Coolant for a 1981 Suzuki RM60 Dirt Bike.

Shop Temperature Sensors for a 1981 Suzuki RM60 Dirt Bike.

Shop Tools for a 1981 Suzuki RM60 Dirt Bike.

Shop Radiator Hoses for a 1981 Suzuki RM60 Dirt Bike.

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.