How to Change the Coolant in a 2020 Suzuki RM85 Dirt Bike
Shop parts for a 2020 Suzuki RM85 Dirt Bike.
Keeping your 2020 Suzuki RM85 running cool is essential for both performance & long-term reliability. Coolant protects your engine from overheating – and from internal corrosion – making regular replacement a critical part of your maintenance routine. The RM85 has a simple liquid-cooling system designed for high performance in compact spaces, but like all dirt bikes, it can lose efficiency if coolant becomes dirty, depleted, or contaminated.
Step-by-Step Procedure: Changing the Coolant
- Preparation
Ensure the bike is cool to prevent burns. Place the RM85 on a steady stand on level ground. You'll need a drain pan, fresh coolant (meeting Suzuki RM85 spec), a socket set, a funnel, & some distilled or deionized water for flushing. Remove the skid plate if your bike is equipped, to access the water pump drain bolt easily. - Draining Old Coolant
Remove the radiator cap slowly to release any remaining pressure. Locate the water pump drain bolt at the bottom side of the engine—it's usually accessible with an 8mm socket. Position the drain pan underneath and carefully loosen the drain bolt. Allow all coolant to flow out fully. Dispose of old coolant responsibly: never pour it on the ground or down drains.
For maximum drainage, open the radiator cap — this helps evacuate fluid quickly. If there is a coolant reservoir (not all dirt bikes have one), open it as well. - System Flush
Once drained, pour distilled water into the radiator filler neck, let it flow through, then reinstall the drain bolt loosely and rock the bike gently. Drain the rinse water entirely. Avoid tap water, as its minerals can cause deposits in your cooling system.
If switching between coolant types (e.g., from water-based to non-water-based), a complete flush is especially important. In stubborn cases, compressed air (with a rubber nozzle) can be used to clear remaining fluid from hoses and cavities. - Reinstall Drain Bolt
Replace the drain bolt & tighten securely. Inspect the sealing washer or gasket for damage; replace if needed to avoid leaks. - Filling with New Coolant
Using a funnel, pour new coolant into the radiator until it reaches the base of the filler neck. Check your RM85's manual for the exact coolant capacity (typically about 950 ml)—do not overfill. - Purge Air from System
Start the bike and run it at idle until it warms up thoroughly. Squeeze the radiator hose gently several times to help trapped air escape. Shut off, let it cool back to ambient temperature, then check the coolant level and top off as needed. - Verify and Finish
Confirm the coolant is at the recommended level both in the radiator and reservoir (if equipped). Inspect all hose connections and the drain bolt for leaks.
Important RM85 Model Notes
- The RM85 is a high-revving, two-stroke motocross bike. It does not have a radiator fan, so it is especially sensitive to coolant quality and proper filling. Never run the engine without coolant, even briefly.
- The RM85's compact cooling passages can trap air—purge air carefully after a refill.
- Suzuki recommends using glycol-based (not pure water) racing coolant for best performance and corrosion protection.
- Always check for leaks after a coolant change. A loose drain bolt or weak hose clamp may cause coolant loss and lead to overheating.
- Never use tap water to flush or fill the cooling system. Minerals may cause deposits over time, impacting cooling efficiency.
Final Thoughts
Changing coolant on your RM85 is a straightforward maintenance task that prevents costly engine damage and keeps your bike racing strong. With regular care, your Suzuki RM85 remains ready for action on track or trail.
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Shop Radiator Hoses for a 2020 Suzuki RM85 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.