Here's a way to increase the airflow into virtually any stock, or other, airbox pretty cheap. You can pick up a pack of 6 of these UNI filtered vents for less than $10 on eBay or from other sellers.
Installation is as simple as drilling a 1" hole wherever you wish to place the vent, and then popping the vent in.
These vents should be installed so they are still forcing air to pass the internal air filter. In the images above, I have then installed to bypass the air filter on my stock minarelli airbox. That is not the recommended way to install these.
Remember, anytime you increase airflow you will need to tune your carburetor or at least check it. More incoming air requires more fuel.
Last Edit: Nov 14, 2017 10:16:45 GMT -5 by 90GTVert