Got my bike working - concerned about bubbles in oil

[Cadyfatcat]

So I got a K75 in pieces from the PO. After the last few days I was able to piece it back together and get it running. Seems like it runs great. After checking the oil window after a short (10 mile) run, I noticed there were some brown bubbles on the top. They seem to dissipate within 15 minutes or so. Should this be something I am concerned about? Or is this how oil always looks after a ride, I just never looked at it through a window...

http://imgur.com/6AbX5

[frankenduck]

The water and oil pump are driven by the same shaft.  There is a seal on it that keeps the coolant and oil separate.  Yours is failing and letting water into the oil - hence the bubbles.

You'll need to replace that seal.

http://www.motobrick.com/index.php/topic,1925.0.html