According to the "Yamaha YZF-R1 Repair Manual 1998-2003," written by Matthew Coombs and Phil Mather, you should change the air filter on your Yamaha YZF600 every 15,000 miles to ensure your filter properly cleans the air going into your engine. You should remove the filter and clean it every time you change the oil to ensure your bike runs smoothly. Although you cannot see the air box with the side cover installed, getting to it is relatively straightforward.
Remove the screws that hold the side cover onto the right side of the Yamaha using a screwdriver. The side cover mounts directly below the gas tank. Pull the cover off the side of the bike. Locate the plastic tabs on the plastic cover that fit into grommets on the frame. Pull the tabs out of the rubber grommets.
Remove the three Allen bolts from the air box lid using an Allen wrench.
Pull the used filter cartridge out of the air box, and replace it with a new one.
Secure the lid to the air box using the Allen bolts and Allen wrench.
Place the side cover over the engine, and push the plastic tabs into the rubber grommets on the frame. Secure the cover with the screw using the screwdriver.
