How to Change the Coolant in a 2026 Yamaha YZ85 Big Wheel (YZ85LW)
Shop parts for a 2026 Yamaha YZ85LW Dirt Bike.Keeping your 2026 Yamaha YZ85 Big Wheel (YZ85LW) in peak racing form means diligent maintenance, including regular coolant changes to ensure optimum engine performance and longevity. The YZ85LW is a youth competition bike built with high-end features – an 85cc liquid-cooled two-stroke engine, Yamaha Power Valve System, and large-capacity radiator with cast aluminum impeller for maximum cooling efficiency. Proper cooling system care prevents overheating during aggressive riding and extends the life of critical components.
Step-by-Step Guide: Changing the Coolant
- Preparation
- Let the engine cool completely to avoid burns – coolant can be extremely hot after riding.
- Place the bike on a level surface, preferably using a stand to keep it upright and secure.
- Gather a clean drain pan, fresh coolant recommended for Yamaha two-stroke dirt bikes, and safety gloves.
- Drain Old Coolant
- Locate the coolant drain bolt on the lower part of the water pump (right side of the engine).
- Place the drain pan under the drain bolt.
- Remove the radiator cap to allow air in and loosen the drain bolt, letting coolant flow completely into the pan.
Tip: Open the radiator cap only after the engine is fully cooled to relieve pressure safely. - Also inspect and, if needed, loosen the small bleed screw or hoses on the radiator to fully empty coolant, including from radiator cores.
- Flush (If Needed)
- If debris or discoloration is present, flush the system with distilled water. Fill, run the engine briefly, cool, and drain again until clear.
- Refill with Fresh Coolant
- Reinstall and tighten the drain bolt to manufacturer specs.
- Pour new, premixed coolant into the radiator slowly, filling to the base of the cap neck to avoid air pockets.
- Squeeze the radiator hoses gently to help bubbles escape.
- Bleed Air from the System
- Start the engine and let it idle. Tap the hoses and top off as necessary as air escapes and the level drops.
- Watch for leaks around the drain bolt and hose junctions.
- Reinstall the radiator cap securely once all air is expelled and the level is steady.
- Dispose of Old Coolant Properly
- Never pour old coolant down the drain; take it to a recycling center or hazardous waste facility.
What Makes the YZ85LW Cooling System Unique?
- The 2026 YZ85LW features a high-capacity cast aluminum impeller and large-core radiator for enhanced cooling during competition riding.
- This model's radiator and water pump are engineered for rapid heat dissipation, making it crucial to maintain coolant quality for optimal flow.
- Always use a compatible, silicate-free motorcycle coolant to avoid clogging the aluminum parts and ensure anti-freeze and anti-boil protection.
Pro Tips for YZ85LW Owners
- Inspect coolant level before every ride – rapid loss may indicate leaks or a failing water pump seal.
- Change coolant every season, after heavy use, or after three major race events.
- Check for trapped air after maintenance, as air pockets can quickly cause overheating in the high-performance YZ85LW engine.
- Clean the radiator fins regularly to maintain airflow.
With regular coolant changes as outlined, your 2026 Yamaha YZ85LW will stay cool and reliable whether you're putting in laps at the track or conquering technical trail sections. Stay on top of maintenance and shop genuine parts for your YZ85LW when you need fast, model-specific support.
Related Shopping Categories
Shop Radiators for a 2026 Yamaha YZ85LW Dirt Bike.
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Shop Radiator Hoses for a 2026 Yamaha YZ85LW 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.