Changed the oil the other night, rode it 22 miles the next day, shut it down and put it up on the center stand and noticed the oil looked milky in the window and the filler cap had a nice milky film on it as well. Is it more likely that it would be the water pump seal or the intake manifold or even something else? The odometer just turned 45,500. According to the previous owner this bike sat idle for approx. 2yrs., I've been shaking it out pretty good for the past 2 months, outside of a minor fluxuation in the throttle at idle this engine has shown no signs of trouble until now.