The specific RPM (Revolutions Per Minute) at which your engine should be running at 80 mph (miles per hour) depends on several factors, including the gear ratios of your motorcycle, the number of cylinders in the engine, and the overall design and specifications of the bike.
Different motorcycles have varying gear ratios, which affect the RPM at a given speed. Typically, motorcycles have a tachometer (RPM gauge) that allows you to monitor your engine's RPM. The ideal RPM at a specific speed can be determined by observing the tachometer while riding.
In general, for most motorcycles, the engine RPM at 80 mph in top gear (usually the highest gear) will be around 4,000 to 6,000 RPM. However, this can vary considerably depending on the motorcycle's design, engine displacement, and other factors.
To get a more accurate RPM reading at a specific speed, you can refer to your motorcycle's owner's manual or consult the manufacturer's specifications. These resources often provide information on recommended RPM ranges for various speeds and gears for your specific motorcycle model.