From the
Mobil 1 V-Twin 20W50 webpage webpage FAQ:
How is Mobil 1™ V-Twin 20W-50 motorcycle oil different from Mobil 1™ for passenger cars?Mobil 1™ V‐Twin 20W‐50 fully synthetic motorcycle oil is designed for air‐cooled, large‐displacement bikes. Because of their design, these engines can generate very high localized oil temperatures and high overall bulk‐oil temperatures. A typical air‐cooled V‐twin's rear cylinder gets a lot hotter than the front cylinder – it's a matter of airflow. When it's hot out and you're stuck in traffic, the oil temperature in a bike climbs rapidly. Above about 250 degrees Fahrenheit, conventional motor oil is going to break down. Mobil 1 V‐Twin 20W‐50 fully synthetic motorcycle oil is good to above 300 degrees Fahrenheit. Like Mobil 1 Racing™ 4T 10W‐40, Mobil 1 V‐Twin motorcycle oil has high levels of phosphorus/zinc and the same high‐temperature detergent technology for superior wear protection and engine cleanliness, even at elevated oil temperatures. With Mobil 1 V‐Twin motorcycle oil, you can go the full length of the manufacturer's recommended oil change intervals with ease.
I would fret too much about 240-250 F if the oil's good to 300+
