This is going nowhere, with the details we have to work with. First, we need to know if oil is coming from under the starter, or the generator. Then, a year model, and type of bike, then maybe some photos. If it is motor oil, it could be coming from anywhere that it can seep. If it is a vent line, it could be coming from anywhere it can seep. There are also some year models, that have a vent tube on top of the cam cover, coming out of the "generator mounting flange", and it runs back(originally to the air box) and some people run them to ground, or a vent filter. If this vent is on your bike, and the vent is ran to the trans area, it could be wet sumping and pumping to rear of motor. But all of this is weak guessing, due to the lack of info. Take some photos of the motor, and the leaking areas, list them "A" and "B", then describe the photos. Then, we can make a better diagnosis.