How can I modify the stock airbox / filtration system?
First, remove your seat and study the top of the airbox. You will see a black plastic plate with a rectangular “snorkel” mounted in a slightly larger cutout in the top of the airbox. You can carefully pry this snorkel out of the airbox top with a flat blade screwdriver as it is simply glued in (non-California bikes), or drill out the rivets for California bikes. Removing this snorkel will allow a much greater airflow into the airbox, and will allow the entire front face and sides of the airfilter to get outside air, as the snorkel dead-ended into a small section on the front of the air filter element alone. Second, you can remove the stock airfilter and cage, and cut out the backfire screen. This screen causes a huge restriction in the airflow, and cutting out this screen will help matters a lot. One method that is used is to take a razor knife and physically cut the screen out, then trim off all remaining metal screen fibers until there is nothing left that can come loose and be sucke
