Sorry to have bombarded the forum lately :/. My carby is playing up and I was going to go 32/36 weber but then I had a thought (dangerous). Ive seen people use twin motorbike carbys by cutting the inlet manifold and plumbing that up to 2 motorbike carbys. Is there any magical carbys I can use on a stock a12 with extractors and not have to jet it ect? I kno I should be tunning any new carby but was wondering if there was something close enough or if someone knew what jets and springs on what carbys I needed?

there's no really easy setup, hence why not many people run bike carbs.
probably better off getting a pair of webers for it man, will be cheaper in the long run.

32/36 waayyyyyyy easier. Whys it dangerous?

Bike carb are NOT bolt on and drive. Sikyne made a manifold for me but I gave wrong angle as I thought they were sidedraughts now down drafts.
Super sensitive to fuel pressure. Mine are running 1psi pressure with a bleed t peice.
1 psi constant can build too much pressure of needle and seat causing flooding and fuel leaks out overflows. That's more dangerous.

then you still have to set float heights then needle positions if they are adjustable (some arent. .. good luck tuning them) then work out pilot jets then main jet . Syncing carbs and cleaning them out too.

id guesstimate ive spent close to 25hours so far just to get a pretty decent rough tune.

this does not include head and cam swap from blowing head gasket or other non related stuff.

32/36.... $60 spacer plate and throttle cable and will run rich but will run with bit more performance too.

honest truth ive done it cheap on old 1200's.

saying that I love the sound of 7000rpm bike carbs even after more grey hairs and ive learnt heaps.
so how much spare time do you have reading mikuni or kehlin manuals and surfing google ontop of that 25+hours on the tools? I have random insomnia so thats my spare time. Great in summer.

If you are looking at pairs look 2 30-36mm or similar from my undrrstanding.

Otherwise zx9 carbs, 4 carbs may work ok too. Lots of work and dont think silicon to the runners with hose clamps will do it, sikyne wisely tokd me use the stock carb to manifold rubbers, they seal and hold the carbs with groved seals and special clamps.

As one of the people running motorcycle carbs I will also say that replacing the 32/36 is much easier and for a mildly tuned A12 just fine.
Note when I bought my set up it came with a custom manifold that was professionally fabricated for a race car. As for tuning the carbs, they were fairly easy for me but keep in mind I have a lot of motorcycle racing experience. In the tech section you'll see my near stock GX motor made 73 rwhp with 39mm flat slides which considering the stock GX motors were rated at 83 hp at the flywheel is very good.
For a road car with twin carbs I would go with a pair of 38mm CV style carbs.

Tom

28/36 is a good carb for smaller donks and usually found in fiats and renaults

28mm smoothbores!

Keihin or Mikuni, and at that bore size they are well priced.

A bit small, even for a stock A12?

New mikuni 32s are like $150. Use one adapted to the stock manifold with a right-angle connector.