How can I keep most of the water from entering my airbox if I keep the lid off?

 

Your question begs the answer, "Don't go near the water!" . Now that it's out of my system, I run a vented lid from Moto Force which gives considerable protection from water, other than submersion. I'm not certain I give away much in airflow compared to an open box, either & definitely more peace of mind.Also you're concerned about the wrong thing ..what you need to worry about is the water that hits directly on the filter & is sucked into the engine.