You can add one or more motorcycles to your personal profile. You can then assign the bikes to the trips  you did or select your preferred bike before the ride. To add a bike, go to your profile (menu "More" - > "My profile") and tap on garage. Click on the plus symbol to add your bike and expand your garage. You will be able to see an overview of all driven kilometers per bike as well as the number of ridden trips per motorcycle.