Intermittent oil leak

[Porsche Monkey]

Its not been a good riding weekend for me apparently. I went for a ride this morning on my bike, 97 M900 and after about 50 miles stopped to gas up.  I noticed that my back tire had oil on the right side. I looked over the bike and the right engine case was covered in oil.  I cleaned it up best I could and headed for home.  As I was riding I looked down and saw the oil coming out from under the belt cover right next to the fill plug. It was a pretty good leak. I got home and took the belt covers off and cleaned everything up. The bike was just a touch overfilled with oil so I drained some off. Then I started the bike and let it idle for about 30 minutes. I couldn't find a leak anywhere.  I ran the bike up to about 5k rpm and held it there for a few minutes and nothing. It looks like it was never leaking. Wtf?  I am guessing the leak was coming from the belt drive gear but it apparently stopped.  Does this happen if the bike is slightly overfilled?  The other thing I was thinking about was maybe the breather stopped breathing. Do the breathers fail in this way? 

Thanks Jon

[Porsche Monkey]

bump

[Speeddog]

Likely it's that seal under the drive pulleys that's failed.

Not sure if the bike being slightly overfilled would have any effect, but I suspect not.

I've not heard of a breather failing that way.

[Porsche Monkey]

Damn, thats what I was afraid of.  Now I am gonna have to come up with a fancy tool to take off the pulley nut.  Guess I can try making a socket.   

[erkishhorde]

Let me know what you come up with. I'm looking at a cam seal replacement too. I'm tight on money now and my dad keeps griping when I take my bike to Nick for service 'cause he thinks I can do it myself. I probably can but Nick is much faster and better at it than me. 

[greenmonster]

75$ at Bevelheaven f belt wheel  holder tool & socket f nut: http://shop.bevelheaven.com/detail.aspx?ID=966 . Get desmoquattro one.
Nice writeup on this issue: http://uwf.edu/ssnyder/DT/pulleyseal.doc

[clubhousemotorsports]

Pretty common for the layshaft seal to leak on bikes that have seen a few miles and or high heat.spray the area in question with some foot powder and run it the oil will show itself pretty quickly. also look at your oil pressure switch beside the cap , the oil is under pressure there and will leak pretty badly if the switch gets an internal leak.

[Porsche Monkey]

It was definetly coming out from under the cover.  Guess ill be buying some cam tools. 

[accrocker]

I had the same issue with my 695. I found the source of the leak to be the belt pulley seal, but the main cause was the bike being slightly overfilled. As soon as the oil level was corrected at the next service, oil leak went away. It was only overfilled by about a third of a quart, but it seems like they are sensitive to that. I would check that out before spending a lot of time and money on pulley tools.