How to Change the Coolant in a 2017 Yamaha YZ250FX: Step-by-Step Guide

Shop parts for a 2017 Yamaha YZ250FX Dirt Bike.

Maintaining the cooling system of your 2017 Yamaha YZ250FX is key to top engine performance and longevity. Refer to this MotoSport exclusive guide for a complete, model-specific process to swap out your coolant, keep your machine at peak, and uncover what else you should know about your MMY (Make/Model/Year) dirt bike.

What Owners of the 2017 YZ250FX Should Know

  • The YZ250FX uses a liquid-cooled four-stroke engine, requiring careful monitoring of coolant type and level for optimal off-road performance.
  • It features a high-revving engine with tight tolerances, so coolant changes matter deeply for temperature control under racing or trail riding conditions.
  • Be sure to inspect the radiator cap and hoses during coolant changes for leaks or wear – YZ250FX is susceptible to damage on technical trails.

Preparation: Tools & Safety

  • Gloves & safety goggles
  • Drip pan
  • Phillips and flathead screwdrivers
  • 8mm socket or wrench
  • Fresh coolant – use a motorcycle-approved, silicate-free, premixed 50/50 coolant for aluminum engines
  • Clean water (for flushing)
  • Compressed air (optional, for full system flush)

Step 1: Engine Cool Down

Never remove the radiator cap on a hot engine. Allow the YZ250FX to cool completely so the system is depressurized and safe to work on.

Step 2: Remove Plastics and Access Radiator Cap

  • Use the 8mm wrench to remove enough shrouds or plastics to access the radiator cap.
  • On the YZ250FX, the radiator cap sits atop the left-side radiator.

Step 3: Drain the Old Coolant

  • Place a pan under the water pump area (right side case bottom).
  • Remove the 8mm drain bolt from the water pump cover.
  • Remove the radiator cap to improve flow – coolant will drain freely.
  • Wait until all coolant has exited.

Step 4: Optional – Complete System Flush

  • For a full flush, reinstall the drain bolt, fill the radiator with clean water, then run the engine for a couple minutes (do not overheat or ride hard).
  • Let cool, drain water, and repeat as needed until water runs clear.
  • If you have compressed air, use it (with caution) to help remove old coolant residues.

Step 5: Replace Drain Bolt and Refill

  • Ensure the copper crush washer on the drain bolt is intact – replace if worn to avoid leaks.
  • Tighten the drain bolt to manufacturer spec: typically around 7 Nm (5 ft-lb).
  • Fill the radiator with your new, pre-mixed coolant. Fill slowly to avoid air pockets.

Step 6: Remove Air Pockets

  • Rock the bike gently or squeeze radiator hoses while filling to help bleed trapped air.
  • Fill up to the radiator neck, then install the cap securely.

Step 7: Start and Inspect

  • Start the engine, allow it to idle for several minutes with the bike upright.
  • Shut off, let cool 5 minutes, remove cap – top off if needed.
  • Check all fittings and hoses for leaks.

Step 8: Reinstall Plastics and Final Check

  • Reinstall all radiator shrouds and plastics securely.
  • Dispose of old coolant responsibly by taking it to a recycling center or hazardous waste facility.

YZ250FX Coolant Change Maintenance Tips

  • Inspect the radiator cap for damage or weak spring – an improper seal lowers boiling point and can cause overheating.
  • Periodically check coolant level through the radiator fill or overflow tank – a drop in coolant may indicate a leak.
  • Always use coolants approved for aluminum radiators & engines, as improper coolants can cause corrosion within the system.
  • Change coolant at least once a year or every 60 hours of riding, whichever comes first, for best reliability.

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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.