How to Change the Coolant in a 1999 Suzuki RM80: MotoSport Guide

Shop parts for a 1999 Suzuki RM80 Dirt Bike.

Keeping the cooling system on your 1999 Suzuki RM80 well-serviced is essential for optimal engine performance – and skipping coolant changes increases the risk of overheating and internal corrosion. This guide, unique to MotoSport, details every step you need to tackle a coolant change and highlights what RM80 owners should watch for.

Essential Tools & Supplies

  • Fresh motorcycle coolant (pre-mixed or ready to mix with distilled water)
  • Drain pan/approved container for old coolant
  • 8mm socket or wrench (fits most RM80 water pump bolts)
  • Screwdriver for plastic/radiator shrouds
  • Distilled water (for flushing)
  • Shop rags & gloves

A. Preparation

  • Allow the engine to cool completely. Remove the seat and radiator shrouds for easy access.
  • Position your drain pan beneath the water pump (lower right engine side).

B. Draining the Old Coolant

  • Remove the radiator cap to release any pressure in the system.
  • Locate the 8mm drain bolt at the base of the water pump. Loosen and remove this bolt — coolant should flow freely into your pan.
  • Gently tilt the bike if needed to clear out as much old coolant as possible.

C. Flushing the System

  • Reinstall the drain bolt finger-tight and pour distilled water into the radiator fill neck until full.
  • Replace the radiator cap, start the engine, and let it idle for several minutes. Rev gently to circulate water, then shut off the engine.
  • Once cool, remove the drain bolt again and let the rinse water drain out. Repeat if the drained water is still discolored.

D. Refilling with New Coolant

  • With the engine cool, reinstall the drain bolt and torque snugly (avoid over-tightening – check your service manual for specs).
  • Slowly pour the correct mixture of motorcycle coolant into the radiator fill neck up to the inner lip.
  • To eliminate trapped air, gently rock the bike side to side and slowly add more coolant as the level drops.

E. Burping the System

  • With the radiator cap off, start the engine and let it idle. Air bubbles may escape from the fill neck – watch until only coolant is visible.
  • Rev gently and tilt the bike side to side again. If needed, add more coolant until the level remains steady at the top of the fill neck.
  • Install the radiator cap securely.
  • If equipped with a coolant overflow tank, fill it to the upper level indicator.

F. Final Checks

  • Start the engine, allow to reach full operating temperature, then shut off and let cool completely.
  • Recheck coolant levels in both the radiator and overflow – top off if needed.
  • Dispose of old coolant responsibly at an auto parts store or chemical collection center – never pour it on the ground.

What Makes the 1999 RM80 Coolant Change Unique?

  • The RM80's two-stroke engine runs hotter than many four-strokes – regular coolant changes are especially important to prevent overheating and maintain power output.
  • Plastic radiators and small cooling passages are sensitive to mineral buildup – always use motorcycle-specific coolant and distilled water to prevent internal clogging.
  • The RM80 coolant system is simple, but air pocket formation is common. Carefully burp the system as described or performance can suffer.
  • Inspect the radiator cap and hoses for cracks – leaks are rare but catastrophic if uncaught. RM80 radiators are relatively exposed, so check for bent fins or external debris during every coolant change.

Pro Tip

  • Consider changing coolant with every third or fourth oil service – even if it looks clean, coolant additives degrade over time, particularly if riding in sand or mud.

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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.