Alternator Oil Leak?

[0m3nc0w]

Hi,

First thanks for all of your help with my questions. I've never turned a wrench before and really appreciate everyone here that is willing to answer silly questions from someone new to old BMW Airheads.

So here's my question, I've removed the alternator cover and was surprised to see oil (not much) drool out of the bottom of the housing (see photo below), wondering if this is normal or if it is a sign of a seal leaking? BTW my oil level is normal (hasn't lost any since I bought the bike a couple months ago).

Thanks, 0m3nc0w

Alternator Oil Leak

Alternator.Oil.Leak.SM.jpg (115.93 KiB) Viewed 1659 times

[Bamboo812]

The photo doesn't show us much, but an oil leak will tend to "wash" its path downward. There are three possibilities under that cover; alternator, camshaft or tachometer drive. It looks more like the seal behind the advance unit is leaking, an easy swap...

[Kurt in S.A.]

High probability it's the seal behind the advance unit. The alternator cover seals around this area and there doesn't seem to be any oil above this area, so likely not dribbling from the crankshaft seal. This is a /7 so it has an electronic tach.

Kurt in S.A.

[Bamboo812]

The electronic tach was introduced in 1978, this one's a '77, is it not?

[Kurt in S.A.]

He says '78 here:

viewtopic.php?f=1&t=9720&p=117376#p117376

Plus, I didn't see the usual cable coming in from the side. Doesn't the mechanical tack cable enter the lower case from the driver's left?

Kurt in S.A.

[0m3nc0w]

Yes this is a '78. Here is a better picture below. It appears the oil is coming from behind where the red arrow, and there is no oil above the red arrow.



Oh and by the way here's what 5 hours of elbow grease will do on one of these alternator covers, give me a couple more months and the whole bike will look better than it did coming off the assembly line