Center Bearing Oiling
If you look on your Oil Tank down about 5 inches you will see an oil line that gravity feeds down to a fitting on the front of the motor between the cylinders. this is to feed the center bearigs.
There are seals on the crank to isolate this oil chanber from the rest of the case.
If these seals are marginal this oil will fill the case, and if you keep topping off the oil tank it will fill more and more.
Suggestion-
If you store your sled for a long time drain the tank oil below this fitting so the
this will not occur.