Unless there is an issue with the performance of the engine I wouldn't worry about the bearing. It doesnt matter if you have the best seals in the world the bearing is still a slip fit on the crank and will leak anyway. Using Wd40 is just compounding the problem because it is very thin and actually a penetrant, if anything will leak out it will. A lot of onroad engines dont run any front bearing seals and only run metal shields, these engines run fine and have no problems.