Hi I have a small oil leak, the back edge of the sump is wet so a little oil is leaking from this area only when bike is being used. Travels back along the smooth area behind the sump (this area has a strange hole in it). Thinking sump gasket maybe? Bike has done 63k miles with good service history. Any thoughts from you guys gratefully gobbled up.

There is no sump gasket the seal is done using 3Bond or similar. You will find many of the BMW sealing faces are made like that, seems to work well.

ush1000 wrote:Hi I have a small oil leak, the back edge of the sump is wet so a little oil is leaking from this area only when bike is being used. Travels back along the smooth area behind the sump (this area has a strange hole in it). Thinking sump gasket maybe? Bike has done 63k miles with good service history. Any thoughts from you guys gratefully gobbled up.

Examine it very closely to be 100% sure it is coming from that joint. Its an easy repair but be careful removing the bolts. Clean them out well before trying to get the Allen key into them. There is a risk of them being seized in place and wringing the recess for the Allen key and having to drill one out. I would heat them first. That sump is not normally removed in routine maintenance so its likely the bolts are in place since manufacture. 

Now you mention the strange hole in the smooth area behind the sump. This is the bell housing. Your sump is less likely to be a leak cause than this strange hole at the back of the smooth area [bell housing]. Unfortunately if the oil is actually coming out of this hole and migrating forward [the belly pan on an RS causes a vacuum and it does exactly this] you have a bigger issue. At 63k miles its not unexpected here.

In short term both are harmless and I would clean it all up to be doubly sure of the oil source. If the sump was leaking that would leak all the time because its holding all of the oil. If its coming from the bell housing hole it will only come when the bike is being used if the oils are at the correct levels. Your observation points to this.

Thanks for helpful replies guys

Olaf I will give the area a good clean, I was wondering if the hole was the source. Does this indicate main seal failure and need to split engine/gearbox?