I stumbled onto a post (with pictures) that shows how you can modify your stock AD seat so that the back easily tips forward, giving you access to the usable area on top of the fuel tank. It also shows how, by removing and reversing the top brackets, you can drop the seat back a couple more inches to give you a more comfortable driving position and belly room!!
The original poster was Chris55.1, it was entitled "What seat do you recommend?" posted 4/30/2005 and the tip was given by Hartmte Bolter #2765 and it can be found on page 9. Click on "show all topics" at the top of this page...it'll give you 15 pages.
Check it out....it works great!!!