I am anal about this still so I would do it during the first oil change at 300 miles, and every 2 or 3 thousand after. Use good 75w90 full synthetic oil and DO NOT overfill the box. These gearboxes often live their lives with the oil that came in them and still outlive the rest of the scooter. But putting some good oil in there right away will get the break-in metal out, and some overkill spec oil in.
Pros: good oil, break-in metal out
Cons: DO NOT overfill
Mileage: 300 km
