Nasty oil leak, What's this hole for?

[SerTorm]

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K, I got a crapload of oil all over the place riding the bike home from a trip. So after tracig the mess, I took the cover off the left side and found this hole leaks copious amounts of oil when the enigine runs.

Anybody know what's up? It looks like the hole was supposed to be there, so did I loose a plug, or some gasket farther up inside?

[Nessism]

That hole is a drain for the starter cavity. Most likely the large O-ring on the nose of the starter has failed. Easy fix. Pull the starter out, replace the O-ring, reinstall. Easy job other than the lack of access.

[SqDancerLynn1]

Starter is the first suspect, could also be cam chain tensioner

[SerTorm]

Starter is the first suspect, could also be cam chain tensioner

That doesn't sound like any fun.

I was looking at that thing and wondering; Why would they put something your not supposed to mess with right out there with an invitingly knurled adjuster on it? I know how close I came to calling it an idle adjuster at first glance, it's amazing that I didn't just reach out and twist on it. I can imagine somebody may have futz'd with it at some point while it was for sale, though.

[bwringer]

Ah, the Mystery Hole...

Yes, oil from the Mystery Hole is usually just the o-ring on the nose of the starter. Easily sorted.

Cam chain tensioners (even easier to fix) also can leak oil, but it's never more than a slow annoying seep.

The starter nose o-ring can really shove out a lot of oil -- never enough to hurt anything if you're paying attention, but enough to make every ride a greasy mess.

And whatever you do, please don't plug your Mystery Hole.

From the top (the tubing is just there to show the hole better):