(http://i.imgur.com/9CIKPwS.jpg)
http://imgur.com/gallery/9CIKPwS
I thought it was plexi, but this says it's Pyrex glass. Interesting idea.
The problem is, you'd be able to see the float for the fuel gauge! :)
as i dont have fuel gauge,it would be even better :)
a new must have improvement
PYREX, or borosilicate glass, can break with a sharp blow just like regular glass. It will withstand heat and temperature changes but not impacts. One could lay up a fiberglass and resin tank that could be fairly clear, certainly clear enough to see the fuel level. The problem with fiber glass tanks is they can come apart upon significant impact, which is why you don't see them anymore on production bikes. My '71 Norton had one, but they were ruled unsafe not long after that. So far metal is still the safest material for the fuel tank. No one ever plans to crash. Just sayin'
on youtube search tinmantech, for a really low temp method of welding aluminum with a torch. the title is how strong is your your weld