Not knowing what sort of crankcase ventilation system is on the motor makes it kind of difficult to make suggestions.
Does the engine even have a PCV system? That is, does it have a PCV valve and hose connected to the intake manifold or carburetor base? A lot of off-road race engine builders don't use them at all. Instead they install breathers in the valve covers. The result is a design that is similar to a road draft tube. Any excess pressure in the motor is vented through the breathers, and if there is a lot of oil mist (droplets) carried with it, then it appears on the outside as an oil leak.
If you really want, you can take the valve cover off and inspect the base of the front breather. All of the breathers should have some sort of deflector plate to keep oil from splashing directly on, or into, the base. If they don't, then you may have to fabricate something to keep that splash oil from coming up through the unit.
Give a holler if you've got any questions.
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David
newbie #4153
