Venting a California emissions SV650 cap so it can be used with a 49-State gas tank is really simple. They have a rubber cone stopper plugging the hole that lets air through the channel to the external vent. The kicker is the more vacuum present, the tighter the seal.

1) Use the key to open the gas cap as if you were filling gas. Remove the four bolts holding the outer ring to the tank (the other four are merely for display).

2) Flip the cap over, so the keyhole is facing downward against your work surface. Important -- Do not lift the gas cap off of the table, or at a minimum make sure the flap that covers the keyhole does not open up. If you do, a tiny spring with an even tinier ball bearing that is used as a retainer will fly off somewhere, never to be seen again.

3) Remove the screws holding the key assembly to the underside of the cap. All of the screws are the same, so there's not really much need to keep track of where each one goes. You do *not* remove the screw to the lower left that holds the metal plate in place for the key flap retainer spring. See warning for step #2. :)

4) Lift the key assembly off of the cap and flip it over. You should now be looking at Figure 1. Notice that on my gasket you can see where the vacuum has sucked the gasket downward to the point where a small gap forms next to the key mechanism, causing the whistling/sucking sound when riding or parked in the sun. This is the problem we're fixing here -- that of an improperly vented gas tank.

5) Remove the gasket. Now you should be looking at something like Figure 2. The pencil is pointing at the plug that I believe is added to California Emissions gas caps.

6) Lift the plastic mechanism pointed to by the pencil out of the cap. It's not fastened by anything and should be easy to lift. Technically it shouldn't need to be removed to accomplish the next step if you have problems removing it.

7) Pull out the plug. See Figure 3.

8) Reassemble in reverse order. It makes the most sense to put the gasket on the cap with the two pins sticking into their respective holes, line up the key mechanism, and put the screws back in. Then put the cap back on the bike.

9) You're done! Note that the way Suzuki tells the difference between CA and regular caps is by a "marker bolt" on the ring. If you have tried to put a CA cap on a 49-State tank or vice-versa, you need to swap the marker bolt, which is slightly longer than the other "cosmetic" bolts so that it'll fit.