I doubt it's the actual gear sensor. There is an issue with the o-rings around the sensor. They will replace those along with the sensor and it should stop the leak, but was it the sensor or the o-rings? If you don't want to wait to ride you can easily (10 minute job) replace the o-rings IF you can find the correct part. I just got 100 of them and can send you some, but don't know where you're located (it's not in your profile). If you're in the states and interested, shoot me a message.
121 Buna-N O-Ring, 70A Durometer, Black, 1-1/16" ID, 1-1/4" OD, 3/32" Width
Found out my bike has been leaking oil. It's always "used oil" and I wonder if this could be where it's been going all along- seems likely. It's coming from the gear position sensor and is slow enough that it never drips beneath the bike and may only happen when the bike is running. If so, the...