I had just over 500 miles on my 08 last week & just came back from a two day 570 mile trip, so I need to change my final gear oil as well. I spoke to the dealer about just doing it myself, and they said that was fine...but to use the specific oil that Yamaha recommends for this bike. I told them that I'd read on a lot of forums that there was other final gear oil that was even better than the Yamaha brand, so I wanted to use that. The dealer said I could...but if there was ever an issue with the final gear section of the bike...I could void my warranty with Yamaha.
So the question is...should I be concerned about that and just use the Yamaha oil, or use some recommended "better" products per the forums & hope I could prove (if I had a problem) that the final gear oil wasn't the issue? The dealer said I "should be careful about what I read on on-line forums".