How to Change the Coolant in a 1987 Yamaha PW50: MotoSport.com Guide

Shop parts for a 1987 Yamaha PW50 Dirt Bike.

If you own a 1987 Yamaha PW50, regular maintenance is key to keeping this legendary mini dirt bike running strong for years. While many modern dirt bikes require careful attention to their liquid cooling system, it is important to note that the Yamaha PW50 is air-cooled. This means there is no coolant to change in the conventional sense, as it does not circulate liquid through a radiator or cooling passages like water-cooled engines do–you never need to flush or replace coolant in a PW50.

Instead, cooling is managed via air flowing across the engine's cooling fins as you ride. Since there is no cooling system to service, you can skip coolant flushes entirely. However, there are essential cooling-related maintenance tasks unique to this model:

  • Keep the engine cooling fins clean. Dirt, mud, and debris can collect on the cylinder and head fins, reducing airflow and causing the engine to run hotter than normal. Use a soft brush or compressed air to remove buildup regularly.
  • Don't block airflow. Ensure nothing (stickers, accessories, heavy mud) is obstructing the side of the engine where the fins release heat.
  • Monitor oil quality. On 2-stroke engines like the PW50, clean, quality oil assists in dissipating some of the engine's heat. Regularly inspect and replace the oil according to your owner's manual or sooner if riding under harsh conditions–this is especially important for young riders and beginners.

Additional PW50 Maintenance Notes

  • Spark Arrestor: Clean the spark arrestor at the intervals recommended by your service schedule to prevent exhaust restrictions which could also affect engine cooling and power output—let exhaust components cool fully before servicing and never run the engine without the air filter or with a dirty air filter installed.
  • Air Filter: Check, clean, and oil the air filter regularly. Dirt impedes airflow not just into the carburetor but around the engine, which can contribute to higher temperatures and faster wear on internal engine parts.

The classic 1987 Yamaha PW50 may not need coolant changes like its liquid-cooled peers, but periodic cleaning and diligent attention to airflow will ensure cool, reliable operation all season.

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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.