Mystery Hole???

[adamchatum]

Can anyone tell me what this hole is for? I've got oil leaking out of it, and I need to fix it. Its located under the starter, in front of the drive sprocket.
Thanks

[bietau85]

What bilke is it? I could look it up. put ur bike in your signature under user CP. Its the top far left tab.

[adamchatum]

Its a 1979 GS750L

[bwringer]

Ah, the Mystery Hole:

Comes out here -- the blue hose is just stuck in there to show they're connected:


From the top:



There's a space in the casting in that area. The upper mystery hole serves as a drain for the starter cavity. The starter cavity is not sealed, so you need to make sure both mystery holes are open so that water can drain out if you ride in the rain.

If oil is coming out, it normally means that the o-ring on the nose of the starter is old and decrepit.

Of course, other oil leaks in this area can make their way into the starter cavity and out the mystery hole. For example, the cam chain tensioner or valve cover. Or if you have a fuel leak, it can end up washing through oil and dirt.

[adamchatum]

Very nice reply I must say... Pictures and all. I hope you didn't disassemble your whole engine just to take those pictures for me.
I'll take my starter out tomorrow and see if its seeping out of that o-ring your talking about.
Thanks again.

[Flaming Chainsaws]

I hope you didn't disassemble your whole engine just to take those pictures for me.

Now that would be AWESOME!

[Nessism]

Very nice reply I must say... Pictures and all. I hope you didn't disassemble your whole engine just to take those pictures for me.
I'll take my starter out tomorrow and see if its seeping out of that o-ring your talking about.
Thanks again.

Brian has posted those photos at least half a dozen times before. Nobody searches so smart men like him keep the photos handy.

[JEEPRUSTY]

Ok the mystery hole is solve but I have an odd depression in my belly.
Where does that go?

I love these smileys. I had no idea they were so cool.

[bwringer]

Brian has posted those photos at least half a dozen times before. Nobody searches so smart men like him keep the photos handy.

Yep, I've got several like this related to oft-repeated topics. That's a defunct GS850 engine in the photos, but the Mystery Hole is common to most, if not all, GS models.

What I think is awesome about this thread is that the OP actually called it a "Mystery Hole". I thought I coined the term, but maybe it's obvious...

We usually get two or three Mystery Hole threads a year, and a few times people have actually gone to the trouble of plugging their Mystery Hole with epoxy before asking about it, which leaves the starter swimming in water/oil the first time you ride in the rain.

[adamchatum]

Thanks for all the help guys! I would have done a search, but I didn't know what the heck to search for! Makes sense now to have a place or the water to drain.

[adamchatum]

Well, I ended up taking out the starter, and there seems to be no oil coming from the starter shaft. I guess the only possible leak could be from the upper and lower crank case split line??? Great!

[Nessism]

Well, I ended up taking out the starter, and there seems to be no oil coming from the starter shaft. I guess the only possible leak could be from the upper and lower crank case split line??? Great!

Crankcase leaks are very rare. Best to take a real close look, most likely it's something more obvious.

[posplayr]

Ok the mystery hole is solve but I have an odd depression in my belly.
Where does that go?

I love these smileys. I had no idea they were so cool.

So you have an "inny" and not an "outy"

[Souske]

So you have an "inny" and not an "outy"

Outties are wierd , like gingers. I suspect they also make the parents love the child less.

[londonboards]

I think a lot of us have given us searching because it often fails and in many instances we can't think of what to search for. In this instance what are the 2 search words (3 words always returns an error) that would return this thread. Do you see what I mean?

Greetings