So 500km in on my new Sertao and there is an oil leak from the front sprocket output shaft. What i can find on the net is it appears to be an easy fix. The seal size is 25 x 40 x 7. As its under warranty i popped past my local dealer but BMW have no stock on this seal so I ordered a Viton seal from bearing man for R48.00 and will get them to fit. For the tech Gurus outhere is this common and could there be a more sinister reason for the seal failing so early? Hopefully its just a case of a faulty seal.