I know this may be old news to some but my Suzuki dealer didn't know about this so chances are some of you don't ether. If you have replaced your grips with some Kury grips or any other grips you have a pretty cool axle cap that I bet you didn't even know about. Fits perfect, just like it was made for it. And yes my dif is black now
On this one I used a end cap off of a VTX but you can do the same thing with the 9 cap. First go buy a couple of extra keys (less that 5 bucks at ACE Hardware), then cut the key so that the cap is flush when you epoxy the key to the cap. After that you really never need to take your key out again because it looks like part of the bike now. I keep one of my spares in my pocket for opening the gas cap.
Some of the best mods are real close to being free.