Title states my problem. First ride on a '98 WR400 that I just picked up. Did oil and filter change before the ride. Got just over 1.5 quarts in it and the stick says it doesn't need anymore oil. On the ride I did some high speed road work(couple of big wheelies in there ) and then some slow speed trails right before I parked it. Left it on the kickstand for ten minutes while I rode the XR50. Came back to check the oil and saw a small puddle of white foam under that vent tube. It doesn't smell like anything in particular. Oil and coolant levels are where they were at before the ride. I did a search here but didn't come up with anything specific on this problem. Help?!?!?