My brother in law has a 2008 YZ450 and he went on a trail ride that incorperated muskeg. When he went to do a service he found muskeg in the fillter and the oil milky.(entered through the crankcase vent we assume). So now the problem. He serviced the bike and now has no oil flow to the tank. It has pressure on the screw half way up the engine but no matter what the tank gets no oil on the dipstick. We then pulled the clutch cover off and the clutch apart. It looked good and the oil was clean. There is still flow through the filter. We also pulled the top valve cover off and there is oil in the top end. The right amount of oil is in the bike and it seems to burn a bit too. We believe some oil galaries are pluged and was wondering if anyone has run into this before. At this piont i think it will be a total tear down. Keep in mind we have not run the bike very long as we are scared to do so. About 5 min total so enough to show in the tank. Thanks in advance.