Can someone tell me from which bike, or displacement is better for a standard A12 engine?

Somthing of a 1000cc motor would be adiquate as motorbike motor's are at a much higher state of tune out of the factory, but if your gona go all out with the motor somthing of a simerly sized 1200cc bike would be better.

I was thinking about the carbs because is easy for a EFI conversion

i am using a set of carbs off a cbr1000 for my a12. Just about got the manifold made. Will post picks when done.

also going to use cb900 carbs for my a10 in the 1000

yeah i'm doing the same. ideally i think you want something around 34mm but they are harder to find and more expensive than the 38 - 40 mm ones. I'm currently waiting for my 07 suzuki gsxr 600 setup from the US. cost me $135 delivered

Puting four carbs on a 'standard' 1200 or A12 is not really such a good idea unless you also fit a cam that will take advantage of the induction's ability to feed it some fuel.

With a standard cam the engine will simply be overcarbureted.

What about the fuel pump? what mods are needed?

Please send us some pics Lampy, i`m getting a Datsun 100A tomorrow for my wife, and i`m thinking of convert it to fuel injection through a bike carb setup.

I have fuel injection off a YZF-R6 yamaha using standard injectors (motorbike) for my A14 w/cam.

I picked up the bodies on ebay for $140 + postage
used my own computer (haltech f7) and ran a return line.

Used a surge tank fed by existing mech. fuel pump to a VL turbo EFI pump

I was just wondering, if i had that YZF fuel injection setup so i could easily tune with a system like megasquirt or someting similar, would i need a cam change?