Originally Posted by bmwktmbill
IMHO, no screen on top as it willl disturb the smooth air flow/ movement-motion into the box and to the filter.
Bill is correct to an extent. This really depends on the carb you have. If you are still running a stock bst 40 he is absolutely correct. In my experience if you open up the airbox to much you establish no pressure(vacuum) in the airbox. The reason this is bad is because that is the way that your carb operates. It creates a lag until that airflow velocity/pressure is reestablished. With a fcr/pumper carb open the intake and exhaust as much as possible and let that (and off course the motor itself) be your only restriction. As far as filtration goes, there are many theories, but as long as you are keeping the dirt out and the air coming in your, theory is as accurate as any other. Beek
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