How to Change the Coolant in a 1990 Suzuki RM80
Shop parts for a 1990 Suzuki RM80 Dirt Bike.
Maintaining the cooling system on your 1990 Suzuki RM80 is essential to keep your two-stroke engine running at peak performance. The task is straightforward but vital for engine longevity and optimal power delivery, especially since the RM80 is a race-tuned youth motocross bike that runs hard – and hot. Here is a step-by-step guide, exclusively from MotoSport, to help you confidently change your coolant and keep the RM80 blazing around the track.
What You Need
- Fresh, pre-mixed motorcycle coolant, or distilled water with compatible coolant additive
- Drain pan
- Metric socket or wrench set
- Phillips screwdriver
- Gloves and rags
Before You Start: Special Notes for the 1990 RM80
- Engine Casing: Vintage RM80s have lightweight alloy engine cases. Avoid using tap water, as mineral deposits can lead to internal corrosion.
- Plastic Radiator Fittings: Be gentle with the plastic radiator and hose fittings – they become brittle with age.
- Expansion Tank: Not all models came with an overflow/expansion tank. If equipped, check it for cracks and clean any accumulated residue.
Step-by-Step Coolant Change
-
Cool Engine and Set Up
Let the bike cool completely. Place the RM80 on a stand, ensuring it’s upright and stable for safe access. -
Remove the Radiator Cap
Slowly unscrew the radiator cap to release any lingering pressure in the system. Never remove the cap on a hot engine. -
Locate and Remove the Drain Bolt
Find the coolant drain bolt at the base of the water pump on the right side of the engine. Place your drain pan beneath it.
Loosen and remove the bolt carefully. Coolant will drain out quickly. -
Drain the Radiator and Hoses
To fully evacuate the system, gently squeeze the lower radiator hose to remove trapped coolant. If your model includes a reservoir, remove it and pour out all fluid. -
Inspect Hoses and Clamps
Check rubber hoses for cracks or stiffness, and confirm clamps sit snugly. The RM80’s parts are often original and may need replacing for maximum cooling system reliability. -
Flush the System (Optional But Recommended)
For a more thorough job, pour a small amount of distilled water into the filler neck, run the engine for a few seconds, then drain. Repeat this step once or twice to purge old coolant or debris. -
Reinstall the Drain Bolt
Replace the drain bolt, tightening securely but avoiding over-torque (aluminum threads can strip easily). -
Refill with New Coolant
Pour fresh coolant slowly into the radiator until it reaches the filler neck. Gently rock the bike side-to-side to burp trapped air. If you have a reservoir, fill it to the recommended line. -
Bleed the System of Air
Start the bike briefly and let it idle with the radiator cap off. Watch for bubbles escaping. Top off as needed, then secure the radiator cap. -
Run a Heat Cycle and Recheck
After one complete heat cycle (bring the engine up to full temp, then cool it down), recheck coolant levels both in the radiator and in the reservoir. Add coolant if below the recommended level.
Final Tips for Your 1990 Suzuki RM80
- Factory service interval for coolant replacement is every two years – more often if you ride or race hard.
- Monitor the radiator for bent fins and the hoses for leaks, both common age-related issues on vintage models.
- Consider upgrading to silicone hoses or a modern radiator cap with a temperature gauge for added confidence.
Staying on top of coolant changes is a quick way to protect your high-revving RM80’s engine so you can spend more time on the track and less in the pits.
Related Shopping Categories
Shop Radiators for a 1990 Suzuki RM80 Dirt Bike.
Shop Coolant for a 1990 Suzuki RM80 Dirt Bike.
Shop Temperature Sensors for a 1990 Suzuki RM80 Dirt Bike.
Shop Tools for a 1990 Suzuki RM80 Dirt Bike.
Shop Radiator Hoses for a 1990 Suzuki RM80 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.