ok, after a brainstorming session with a few mates some ideas are forming.
please feel free to point out any obvious flaws in my plan.
1. mount a barrel or keg fuel tank of about 1-2 ltrs on the handle bars.
2. have a braided fuel line gravity feed down to the original tank and carby.
3. this is where it gets cool, cut the guts out of an old 4 barrel carby so it fits neatly over the top of the original carby making it look like the old briggs is sucking from a double pumper. the braided fuel line will connect to the side of the 4 barrel like its supposed to but will feed the original tank/carby set up.
4. a few measurements show that i should be able to mount a bug catcher air scoop on top. hopefully i can make a linkage to get the butterflies to open when i rev the engine.
i'm working out where to run the exhaust but it's still just beer talk at the mo..

in other news, i bought another one, a 17 inch, photos soon.