Alternator Housing Oil Leak?

[czav]

1979 GS550L

This bike has had a mystery leak that has had me chasing since I got it running. I think have finally traced it to the source (after fixing every other leak.) Here is a list of gaskets and seals that I have replaced.

Valve Cover Gasket
Tach Cable Orings and seals
Head gaskets and orings
Cylinder Base Gaskets and Orings
Breaker point side gasket
Right and left engine side cover gaskets
Shifter, Output Shaft, Clutch Push Rod, and Kick Start Shaft Seal
Oil Pan Gasket
Cam Tensioner Gasket and Orings
Oil pressure switch orings and Seals

Which leaves, if i've got this right, The crankshaft Seals and the starter oring.

Ther is no sign of oil leakage in the breaker point area. But I took the bike out and ran it without the right side cover and noticed oil running out of this hole shown in the picture.

Seems this hole is a vent into the alternator cavity. Which would indicate the crank shaft seal is leaking into the alternator area.

Two questions:

1. What is this hole for and should it be plugged?

2. Is the alternator cavity supposted to have oil in it? The Oring on the starter and the gasket on the cover suggest so. But the crank shaft seal, wire opening and the hole in the picture suggest there should be no oil in there.

Sorry for the long post. Hope someone has some info.

[80GS750]

that is a drain hole for teh starter cavity....

i recently was chasing an oil leak in the same area, so i know it well


the starter O ring can leak oil, it will go under the starter and out that hole..

you are correct the alternator cavity holds oil.... that gasket and the starter O ring are all that holds it back in that area...

do you have both your starter bolts installed?? theres 2 bolts that hold it in, both of them go straight into the block and oil will shoot out of them and run down and out that drain hole if they are not installed....

i know this cause i left one out and dealt with the massive leak that insued for about a week.. until i found the empty bolt hole

the other area that can leak is the cover for your oil pressure sensor....

[czav]

I assume you are talking about the two bolts at the back of the starter that run in vertically. In which case the oil would have to run into the starter motor cavity and past the oring at the front of the starter to get out through this hole??

I have checked the pressure switch housing and replaced the two orings and the bolt seals. I'm pretty sure the oil is not coming from there. But not positive.

This oil leak is pretty bad when it gets with it. Even an AMF Harley would be embarrassed.

[80GS750]

yes, the vertical bolts that hold the starter in....

the hole you show is a drain for the starter cavity directly, where the starter sits..

there is no drain hole for the cavity where the alternator is, since its a sealed cavity..

if you have a starter bolt loose or missing, the oil will come out the bolt hole, run along the starter cavity and then out that drain hole in your picture... if thats the issue,

if not, its possible the starter shaft O ring is leaking and then its just running straight down into the starter cavity and out that hole...

i know its weird, but thats the way it drains out around that area of the engine...

[bwringer]

The o-ring on the nose of the starter can and will leak profusely, especially if it's original and has been disturbed.

It's maybe 50 cents, fer Pete's sake. Replace it already. It's a standard metric size, if you have a source for metric o-rings.

[czav]

I work in a power plant so the trouble isn't access to orings. Its figuring out which of the darn cases to look in. I will replace it.

I did a bit more reserch (disassembly) tonight. I found two key things. The starter bolts were both in place and well sealed. However It seems the oil was coming from the alternator housing past the rubber wire bushing into the small side space. Then it would follow the wires into the starter cavity, and the rest is pretty self expanitory.

The bushing appeared out of place. There was oil trapped in the small cavity and the front of the starter near the hole has been cleaned by the oil mist. It also looks like oil has been running past the oring. A picture paints a thousand words especially if you haven't had this cover off yet. So you can find them attached.

I'll make these repairs. Hopefully it works (but I have been wrong before). I'll let you all know how it goes. Thanks for the help.

[czav]

Hate to do it but I needed another post for the other picture.

[80GS750]

it is possible for oil to come through where the wires come through, but the gasket should cover most of that and it should not leak...

but the starter seal will leak if old... mine sure did...

and judging by your first pic there you have a lot of metal shavings and and around your starter cavity....

why?

[czav]

I had to check the picute againg because I had no Idea about any metal shavings. What appears to be shavings is actually just oily dirt buildup. The flash reflected off of the oil sheen making it look like metal.

I think the bushing around the wires was a bit out of place judging by the marks the case left on it.

[80GS750]

oh ok, you had me worried there.....

those grommets can get out of whack pretty easily during installation, there should be no oil getting past that grommet onto the wires.....

[czav]

Follow up

I finally received the new gasket for the alternator cover. I put in the new starter oring and gasket. I cleaned the gasketed surfaces thoroughly and applied a thin layer of rtv to all mating areas including the ones around the half moon wire seal. I made darn sure the wire seal was in the correct position as I reinstalled the cover and put it all back to geather.

Then the moment of truth... I took it out and rode it like I stole it (sure fire way to get the leak to show up in the past). AND IT DID NOT LEAK A DROP!!!

This had been quite a fight. I appreciate everyones help.