can the four carbs be replaced with 1

[Guest]

Is it possible to have a intake that has 1 carb. I was talking to someone at work and he said something about Harley's have 1 carb? When I get a new exhaust what is difference between a 4 into 1 or 2 into 1 with the cost and performance. I can get take offs from Harley's on the mufflers can I use them or is there something different with size? It is alot different with a bike than a truck or car.

[spyug]

That's a whole bunch of questions in one post and without more info on your bike, hard to be specific.

In theory, it should be possible to convert from 4 to 1 carb but a lot of plumbing & calculating ( carb performance) would need to be done and it begs the question: why would you want to?

As to the pipes and muffs. Stock pipes are 2 into 2 and the bikes intake is optimized for this. If you go 4 into 1 or any variation, to get performance gains you need to rejet carbs and likely change out aircleaners as less restrictive pipes/mufflers will make the bike run lean ( i.e. more air than fuel). Harley mufflers could be used but they are definitely less restrictive than stockers.

Bikes are actually simpler than cars but it is a new learning curve for sure.

Give us more details and what you are trying to accomplish and likely we can help a bit more.

Cheers and welcome aboard.
Spyug

[spchips]

V-twins are easy to make 1 carb for 2 cylinders because the distance to both is the same and in opposite directions.

In a normally aspirated inline-4, there would be substantial flow differences on each cylinder for just about any manifold, and certainly any that would fit within the original design envelope. To make this work, every cylinder would need similarly spaced runners.

The most common time to see a 4-1 carb is on a turbo'd or supercharged bike. Because the intake is under positive pressure instead of negative pressure, the difference in pressure from place to place inside the manifold is a smaller percent of the absolute pressure.

for example:

in a normally aspirated intake manifold, the absolute pressure may be 10 psiA (atmospheric is 14/7 psiA) so this gives about -5 psi pressure change. If we had a common intake manifold, maybe we would have one area at 10 psi, and another spot, closer to the intake at 11. This is about 10% difference in air volume from one to the next, which is certainly enough so they couldn't have the same jetting, and wouldn't make the same amount of power, which would amount to a rough ride.

Now, in a turbo'd manifold of the same type, you might have 25 psi in one spot, and 24 in another. This is now a 4% difference.


If this is BS, somone can call me one it, but I'm pretty sure this is how it works.

[Flaggo60]

Years ago, British sedan cars (Austin, Morris, etc.) often had only one carb serving four cylinders. I wonder how the manifold was configured in those cases to permit equal charging of every cylinder, or did they do with an imbalance? Maybe they did, as certainly the performance was modest.

[spyug]

My first car was a Morris Minor and I had Minis, other Austins and other Brit iron that as Flaggo says ran single carbs into 4 cylinders. As I also says power was modest and likely due to the plumbing of the manifold which had the 2 center cylinders closest to the carb and no they weren't balanced ( other than center to center and outer to outer). Bolting on twin carbs was an easy way to pick up another 5 to 10 horse. If you had the coin, 2 barrel Webers or Dell'Ortos were the way to go as you then had (effectively) one carb per cylinder. Combine those with a bit hotter cam, ported ,polished and skimmed head and free flowing exhaust and you could easily double the hp.

Those were the days.

Keep it simple and stick with stock carbs (rejetted) and a freer flowing exhaust.

Cheers,
Spyug

[bwringer]

Lots of four, six and eight cylinder cars had one carb.

They also had plenty of room for an intake manifold large enough to achieve some semblance of evenly distributing the mixture.

In addition, a large, heavy engine in a large, heavy vehicle faces much reduced demands for high output and instant response.

Multiple carbs offer increased performance and responsiveness by mixing up exactly what the engine needs when it needs it, and they save space.

As noted above, Harleys normally use one carb, placed in the center of the V.

Some other V-twin motorcycles use two carbs -- my VX800 has two carbs, each placed on the rear of the cylinder, and some carbureted Ducatis use the same arrangement. I believe later Ducatis placed two carbs side-by-side in the middle of the V.

[Guy]

Why would anyone want to convert a GS to a single carb?

[scrapper]

I was thinking 1 carb to rebuild, not worring about sync the carbs. I do remember I had a chevett that the only hp performance upgrade was 2 barrelled holly or trying to hook up 4 webbers. The exhaust is looking to need replaced was wondering what to look for. It is a 82 gs650L. I can not find very many parts for a L was wondering if other models will work okay? I got a piece for the front brakes at bike bandit it was a different model but looked the same. The book I have also leaves out 650L. Thanks for the help. I will be looking on ebay for parts this winter.

[derwood]

Why would anyone want to convert a GS to a single carb?

........or performance upgrade a chevette?

[themess]

I was thinking 1 carb to rebuild, not worring about sync the carbs. I do remember I had a chevett that the only hp performance upgrade was 2 barrelled holly or trying to hook up 4 webbers. The exhaust is looking to need replaced was wondering what to look for. It is a 82 gs650L. I can not find very many parts for a L was wondering if other models will work okay? I got a piece for the front brakes at bike bandit it was a different model but looked the same. The book I have also leaves out 650L. Thanks for the help. I will be looking on ebay for parts this winter.

If the carburetor is properly built and adjusted and synchronized, you can go many years without touching it, as long as you don't let gasoline sit in it long enough to form deposits. When I lost my GS650G to a crash, it was 14 years old, the carbs had never been touched, and it ran very strongly.

[rudy]

I've heard of guys putting bike carbs on their small displacement 4 cylinder cars. I don't remember where I read it, but it wasn't your usual Brit cars either. These were guys with Nissans and Hondas and the like. Can't see it being much of a performance upgrade from a good injection system, but I don't remember much of the details. Maybe they were old models with carbs still. Don't remember.

But still, keep the 4 carb setup on your bike.

[scrapper]

wasn't wanting to keep 80 chevette stock. Tinted windows wide tires on the back. would have tried to install a buick 231 in it, was way to poor. I ran that thing hard and it never complained once. and if you can make something better , why not?

[scrapper]

I will keep it a 4 carb setup It just seems like extra work. I thought maybe this rebuild sync thing was every couple years? I have alot of trouble finding parts for gs650L, lots of parts , they don't have L after them.

[waterman]

Engine wise, the parts for a 650g will also fit a 650gL like yours. Exhausts will mount right up. You just need to weary of 650e motor parts, the top end will work but not bottom. Chassis parts will likely need to be specifically from a gl model, but you may find a 550l or even 850l may have interchangeable parts, rims, brakes etc.
I seem to find more gl models torn apart on ebay than straight g models. Look around or ask here most parts do show up.

[robertbarr]

A single-carb setup would mean nobody buys my O-rings. What a catastrophe! You trying to bankrupt me, Bub?