I used to go every year when BMW club organized a school. Hope to drop by this year early July. For carb, when the choke knob is pulled, the choke plates should close, and at the same time, on the side of the carb, you should see a cam lever turning that pushes open the throttle. Maybe the cable is not going to full choke/increased idle, or, as suggested, maybe it needs to be bent a little.