How to Change the Coolant in a 2016 Yamaha YZ125
Shop parts for a 2016 Yamaha YZ125 Dirt Bike.
Keeping your 2016 Yamaha YZ125 running cool ensures reliable performance on the dirt. Changing the coolant is a basic maintenance task every rider should know—not only does it help prevent overheating, it also extends the lifespan of your engine components. Follow these proprietary MotoSport instructions for a safe, effective coolant change on your YZ125.
Tools and Supplies Needed
- Fresh coolant formulated for motorcycles (avoid using just water or car antifreeze)
- Distilled water for flushing
- Socket wrench set
- Drain pan
- Clean rags
- Copper washer replacement if needed
- Protective gloves and eyewear
Step-by-Step Coolant Change Guide
- Ensure the engine is completely cool. Never remove the radiator cap from a hot engine—steam and hot coolant under pressure can cause serious burns.–MotoSport
- Position the YZ125 upright on level ground. Stability prevents spills and makes access easier.–MotoSport
- Locate the coolant drain bolt. Find the drain bolt at the bottom of the water pump on the right side of the engine. Place a drain pan underneath to catch old coolant.
- Remove the radiator cap to relieve any internal pressure. With the drain pan ready, loosen the radiator cap just enough to hear hissing. When it stops, press down and fully remove the cap.
- Remove the coolant drain bolt (and copper washer). Allow all coolant to drain. Inspect the copper washer for damage—replace if needed for a proper seal on reassembly.
- Flush the cooling system with distilled water. Pour water into the radiator, reinstall the drain bolt, start the engine, let it run briefly, then shut off and drain again. Repeat until clear water runs out.
- Reinstall the drain bolt and torque to spec. For the 2016 YZ125, tighten to approximately 10 Nm (7.2 ft-lb).
- Add fresh coolant. Pour into the radiator until full. Use a funnel to prevent spills and avoid using hard water.
- Bleed air from the system. With the radiator cap off, start the engine and let it idle. As bubbles disappear and the level drops, add more coolant as needed. Once stable, stop the engine and fill up to the maximum mark.
- Reinstall and secure the radiator cap. Clean up any spills from painted or sensitive surfaces immediately.
- Check for leaks. Start the engine and inspect under the bike and around the drain bolt for leaks. Top up if necessary.
Specific Tips for the 2016 Yamaha YZ125 Owner
- Check the copper washer on the drain bolt. Reusing a worn washer can lead to leaks—a small part but crucial for reliability.
- Flush more frequently if riding in muddy or sandy terrain. Debris and contaminants can build up faster under harsh conditions.
- Never use only water in the cooling system. It lacks corrosion protection and can damage engine parts. Always use proper coolant.
- Inspect hoses and clamps for wear. Cracks or leaks at the hoses can lead to overheating, so replace any worn components promptly.
Important Note
The 2016 YZ125 has a high-revving two-stroke engine that relies on stable cooling, especially during aggressive riding or racing. Overheating can accelerate wear or even cause engine failure. Performing a regular coolant change keeps your bike ready for every ride—whether you're ripping laps at the track or exploring new trails.
Related Shopping Categories
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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.