In the context of motorcycles, the term "choke" refers to a device that helps with starting the engine, particularly in colder conditions. However, the concept of an "open choke" in relation to motorcycles is not commonly used. It's possible that you may be referring to the throttle or air intake control, which can be mistakenly associated with a choke.
In older motorcycles, a choke lever or knob was used to restrict the airflow to the engine, enriching the fuel mixture for easier starting when the engine was cold. This device, also known as a "choke," reduced the amount of air entering the carburetor, allowing a richer fuel-to-air mixture to ignite more easily. Once the engine warmed up, the choke was gradually opened to increase airflow and restore the normal fuel mixture.
Fuel injection systems automatically adjust the air-to-fuel ratio based on engine temperature, eliminating the need for a manual choke control.
If you are referring to an "open choke" in the context of a throttle or air intake control, it would typically mean that the throttle is fully open or the air intake is unrestricted. In this case, the purpose of an open throttle or air intake is to allow maximum airflow to the engine, thereby increasing engine power and performance.
To summarize, the purpose of a choke, which is less relevant in modern motorcycles, is to aid in starting the engine by enriching the fuel mixture. As for an "open choke," if you mean an open throttle or unrestricted air intake, it is to maximize airflow and enhance engine power.