12GS fuel leak

[aspad]

Walked into the garage this morning and noticed strong fuel smell.

Thought tank was evaporating a lot due to the summer warmth (about 28C here today) + I had only run the bike 13Kms after filling up.

Checked again tonight and noticed a small teardrop of fuel on the bottom of left sidepanel. I remove the panel and see that the fuel is obviously coming out of the housing for the fuel pump - it is just a weep but a very definite one. I cleaned it off but it was back within a minute. On closer inspection I can see that a small amount of fuel has been dripping onto the garage floor but the leak is so slow that the drips have evaporated

The fuel line is fine and the problem is definitely where the whole fuel pump housing seats in to the tank.

Perhaps the seal has blown?

There has been no incident that I am aware of to have started the leak.

Anyone had anything similar happen or have any idea what it could be?

I have the bike booked in for a service in a week or so but am wary of riding the thing with even a small amount of fuel dripping onto a hot engine.


A couple of other points.
Bike is parked on centrestand
It is 3 years old and has about 48K Kms on it.
Has had one major rebuild when the dealer stripped the bike under warranty to replace a leaking oil seal between the engine and gearbox - but that was about 18 months ago. Would they have removed the fuel pump and not re-installed it properly I wonder?
BTW I searched the forum but did not find anything resembling this - just a couple of deformed fuel tanks which I do not think this is.

 

[RickG]

Sounds like the seal is to blame, though worth checking the locking ring hasn't worked loose a bit and it's not as tight as it should be.

Dealer won't have been in there unless fuel filter was changed. Can't remember what the service interval for that item is though.

If no-one has been in there it sounds just like a bit of bad luck but just check the breather isn't blocked and the tank isn't pressuring in all that nice Aussie sunshine.

 

[GEOFFREY DEACON]

It could be your over flow from the tank which exits to the right side of the bike.
If you over fill your tank, the fuel gets hot under the sun and expands and weeps out of the overflow.
Either keep you bike cool or only fill up when you are going to use a good amount of fuel.

 

[aspad]

Here is a useful reply from Opus over on advrider. I'm pretty sure this is what it is. Dropping at the dealers tomorrow.

The fuel pump is held in place by a metal ring, torque spec is 28Nm, you can attempt to tighten it by tapping the ridges on top of the ring with a drift and mallet. BMW had a special tool to tighten it, once it starts leaking you will probably need to replace the gasket, it tends to swell when exposed to fuel. It is a simple fix, the gasket is cheap, although you might want a dealer to do it so it is torqued to the spec value.

Opus

 

[aspad]

Just to close the loop on this one - it was the gasket.
No precipitating cause just degraded. Never been touched according to the dealer. They claim the filter never needs to be changed on the 12, therefore they have never laid a hand on it.
Not good on a 3 year old bike...