Been There Done that recommended to me when I put K&N 2780 on............ Ugh what a mess, never again
Much Better Option
Tried that Too ..... does not stop Oil Mist and also I have notices that after riding in Heavy down pours (Rain) that some water collects in the the open topped airbox so that could end up in the engine.
Stick to the small filter on top of the engine breather or as
@Wrecka said "run a piece of fuel line off the outlet from the crank case , it runs under the tank and reduces to a smaller fuel line this is then plugged into the back of one of my air cleaners " or put filter on end of extension
Also point to Note is that the K&N 2780 filters are only just adequate for a bone stock engine, the Ramair are far superior in regards to air flow and if fitted properly the newer version seems to have addressed the splitting problem
Or if you are not worried about keeping the Bearclaw intact you could opt for the K&N RX-4040-1 which flow the best these are what I use