No, it is not recommended to convert the Honda CBR 250R from a 6-speed transmission to a 5-speed transmission. The transmission configuration of a motorcycle is an integral part of its design and performance. Altering the transmission setup can lead to various issues and negative consequences.
Here are a few reasons why it's not advisable to change the number of gears:
Compatibility: The engine, clutch, and transmission are designed to work together as a system. Changing the number of gears could affect the compatibility between these components, potentially leading to mechanical problems or reduced performance.
Gear Ratio and Performance: The gear ratios of a motorcycle's transmission are carefully selected to optimize performance, power delivery, and fuel efficiency. Changing the gear ratios by reducing the number of gears may negatively impact acceleration, top speed, and overall performance.
Rideability: The gear ratios are designed to provide a suitable spread of power across different riding conditions. Removing a gear could result in larger gaps between the remaining gears, making it harder to find the right gear for specific riding situations, such as climbing hills, overtaking, or cruising at a particular speed.
Engineering and Safety Considerations: The motorcycle's overall design and safety features are developed with a specific transmission configuration in mind. Altering the transmission could affect other aspects of the bike's engineering, including weight distribution, frame design, braking systems, and overall stability.
In summary, attempting to convert a 6-speed transmission to a 5-speed transmission on the Honda CBR 250R is not recommended due to the potential negative effects on performance, compatibility, rideability, and safety. It's best to keep the motorcycle in its original configuration or consult with qualified professionals or authorized service centers for guidance and advice.