If I no longer want to use BMW Motorrad CarData, will BMW Motorrad automatically delete the data about my motorbike stored on BMW servers?

No.

If you no longer wish to use BMW Motorrad CarData, you can carry out a BMW Motorrad CarData reset in the BMW Motorrad customer portal. This will reset all BMW Motorrad CarData settings and delete all BMW Motorrad CarData archives you have requested.

The telematics data required to provide other ConnectedRide services will continue to be sent to BMW and stored if necessary.