The Bevel Gear cover normally has some sort of rubber gasket i am guessing. Right now, Lydia's bevel cover has been kludged with some sort of epoxy and it also has a very slow leak. ( photos of the kludge ). Replaced 5-Feb-16 with new cover already seated. Shop Installed Carb kit to replace previous owners' linkage kludge ( including stock kodder pins to replace his homemade paper-clip pins ). Also several new gaskets and seals. The engine would begin racing and need to be shutdown after it heat up 15 minutes ride. Next up is problem with cooling fan and replacing coolant. Fan is stuck "off". A good electrical trouble shooting of that entire circuit should do the trick.