How to Change the Coolant in Your 2013 Yamaha YZ85 – Complete Owner's Guide
Shop parts for a 2013 Yamaha YZ85 Dirt Bike.
Maintaining proper coolant in your 2013 Yamaha YZ85 is essential for keeping your two-stroke engine running reliably – especially during intense rides and in high-heat conditions. Unlike four-stroke trail bikes, the YZ85 is a high-performance motocross machine designed for competition, meaning that diligent maintenance will extend the life of your engine and maximize its performance. Below you'll find MotoSport's proprietary step-by-step process for changing your coolant, including key details specific to the YZ85 model.
What You'll Need
- Fresh, Yamaha-approved coolant (check your manual for specifications)
- Drain pan
- 10mm socket or wrench
- Large flathead screwdriver
- Funnel
- Clean rags
- Distilled water (optional, for flushing)
- New drain bolt washer (recommended)
- Safety gear (gloves and goggles)
Step-by-Step Instructions
-
Ensure the engine is cool.
Never open the radiator cap on a hot engine to avoid burns from hot coolant or steam. -
Remove the radiator cap.
Locate the radiator cap on the left side of the bike. Loosen and remove it to relieve system pressure. -
Locate and remove the coolant drain bolt.
On the YZ85, you'll find the coolant drain bolt at the lower left side of the water pump cover (right side of the engine case). Position a drain pan under the area and remove the bolt with a 10mm socket. Allow all coolant to fully drain out. -
Flush the system (recommended).
For maximum cleanliness—especially if your old coolant is dirty or you are switching coolant types—replace the drain bolt and fill the radiator with distilled water. Reinstall the cap, start the engine for a minute (do not overheat), then shut off, let cool, and repeat the drain process. Repeat this step until the water runs clear. -
Reinstall the drain bolt with a new washer.
Tighten the bolt securely (do not over-torque—check your owner's manual for spec). -
Fill with fresh coolant.
Slowly pour fresh coolant into the radiator using a funnel, pausing occasionally to let air escape and fluid settle. Fill to the base of the filler neck, as specified. -
Burp the system.
Briefly start the engine (cap off), let it idle for 1-2 minutes to circulate coolant and expel air pockets. Watch for coolant level drop and top off as needed. Shut off and allow to cool, then top off if necessary. -
Reinstall the radiator cap.
Secure the cap. Clean any spilled coolant thoroughly. -
Check for leaks.
Start the engine again, let it run, and inspect the drain plug, hoses, and radiator for leaks.
YZ85 Model-Specific Tips from MotoSport
- The 2013 YZ85 uses a high-output two-stroke engine and compact radiator. The cooling system's small volume means it is sensitive to air pockets – be thorough when "burping" the system.
- Always use coolant formulated for motorcycles – avoid automotive coolant with silicates or phosphates that may cause premature wear or clogging.
- Regularly inspect hoses and the radiator cap on this model; aging seals can cause minor leaks and loss of pressure, especially after frequent coolant changes.
- If you ride in muddy or sandy conditions, inspect the radiator for debris & clean the cooling fins as part of your maintenance routine to prevent overheating.
A clean, efficiently running cooling system helps your YZ85 maintain peak power on the track or trail. Changing your coolant is a simple job, and MotoSport makes it easier with quality parts and support for your 2013 Yamaha YZ85. Always refer to your owner's manual for torque specs and coolant type recommendations for best results.
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.