Has anyone tried one of these? They look nice and are claimed to be a direct fit. The price is pretty decent, too. http://www.amazon.com/Keiti-CNC-Billet-Gas-Cap/dp/B000WJEV7M
It looks nice, but it's listed to work on the TE/SM 610. That's not right. The 610/630 has a completly different fuel cap set up.