My friend has a 2007 M109R. He bought the bike new and after about 11 years and less than 10,000 miles the final drive seal began leaking (synthetic gear oil). Obviously the bike sat a lot over those eleven years. We replaced the seal with an OEM seal and used a non-synthetic gear oil. About three years and 3,000 miles, the seal began leaking, and after an 80 mile run the rear wheel is splattered with lube.

Since the seal didn't leak right away, I wonder if anyone has an idea of why it is now leaking. Could sitting for long periods of time cause the problem? Would improper installation cause a problem after three years and 3,000 miles?

I have read several posts about leaking and replacing the final drive seal, but I'd like to know if there is any new information out there.