No, it is not recommended to be going 72 mph (or approximately 116 km/h) in 2nd gear on a 2018 Honda CBR300R or any motorcycle for that matter. Riding at such a high speed in 2nd gear can put excessive strain on the engine and may lead to premature wear or damage.
Each gear in a motorcycle is designed to operate within a specific speed range to provide optimal performance and prevent excessive engine stress. While the exact speed range for each gear can vary depending on the motorcycle model, as a general guideline, 2nd gear is typically used for lower speeds and quick acceleration from a stop.
To achieve smoother and more efficient operation of your motorcycle, it is important to upshift to higher gears as the speed increases. Riding at high speeds in a lower gear can result in high engine RPM, increased fuel consumption, and potential engine strain.
If you find yourself consistently reaching high speeds on your Honda CBR300R, it is advisable to shift up to a higher gear to allow the engine to operate within its intended speed range. It's important to follow the recommended shift points and use the appropriate gear for the speed and riding conditions to ensure optimal performance, fuel efficiency, and longevity of your motorcycle's engine.