Generally :
the Fueltank-dummy is Part of the Airbox,that means the full Volume of this
dummy can be added to the Airbox I've shaped. I havn't had such a close
look,measured nothing.....but a raw estimation is 32 Liters Air-Volume
total,that's triple Times more than OEM.
The Weight -side : if I consider,that only the OEM Airbox lid is at 600 gr (
unfortunately at present I cannot find the OEM Airbox lower part) I assume my
whole Airbox + dummy Assy is still much lighter than the OEM Airbox only.
July 31:
yesterday I brought the first carbon-sight dummy out of the mould, with 505 gr
,or 1.11 lbs.
But there are some reinforcements necessary at special Sections,that's why I
think it'll end up at 580 gr,maybe 600. Won't die.
July 13 :
the Fueltank-dummy Model ,
re-shaped at a lot of Sections, you may notice that the edge is gone,which was
running around the Fueltank.......The Fueltank ( the dummy): at OEM setup
there's too much distance between the fueltank rear end and handlebars and
addittional the seat-height is too low,that's why I moved the dummy ~ 2"
closer to the front. As nice btw-effex it leads into 3cm height-lift,which could
give the right # for riding height.But to avoid that the fueltank-dummy top also
comes 3cm higher I removed a 3cm stripe of Material out of the dummy.
.
I nearly have forgotten where I started
with the Fueltank(dummy)
.....here's the ( fat) OEM-thing : 
.... the side view of my dummy after coating