1 vs 2 cyl? By prodigit (Read 952 times)

[prodigit]

How do 1 vs 2 cylinders usually measure up?

Gas mileage (MPG), speed, torque?

And does 1 x 500cc cylinder equal the power of 2 x 250cc, or more like 2 x 200?

I had a 2.4Liter 4 cylinder car, and a 2.4 liter 6 cylinder car, and the 6 cylinder car was much more powerful, but also consumed more gas!
From the car's perspective, a 2 Liter, 6 cylinder would come close to a 2.4 liter 4 cylinder car.

Is this also so with 1 vs 2 cylinder on a bike?

[wolfhound]

Have never owned a 2 cylinder scoot but have owned a Tank 250 at one time. It was 10 mph faster than the 150
but did not get as good a gas milage. My present TGB Del. 150 gets 68 mpg and my TGB R9i with sidecar gets
48 mpg and top speed is 54 but average speed is 45-50. Before the sidecar was added it got in the 60s
mpg . The 150 tops out at 60-63 but runs best at 55-60.
Hope this helps.

[bobf]

My guess is this. With one cylinder for a given output is much noisier than a 2 cylinder with the same given output. One large cylinder makes a large bang while 2 smaller cylinders make two smaller bangs. Muffling is a bit easier, operation should be a bit smoother, and more gas used.
.

[alleyoop]

On a Scoot 2 cylinders gives you more power to pull the weight but does not necessarly give you more top end UNLESS of course the gearing is changed with taller gears. Take a a 250 Twin what you have is 2 125cc motors on it. With the extra power the two motors can now pull more weight a lot easier. With the extra power you can now turn the taller gears for more top end without sacrificing your low end pulling power. And of course the more cylinders you have the more gas your going to use. More gas is also needed for higher speeds and once you get up there now the wind resistance plays a role. To keep the same speed against the wind resistance you give it more gas.

Just think of 1 horse pulling a heavy wagon the poor horse is struggling, but add another horse to the wagon now they do not have to struggle so much to pull the wagon.
Alleyoop

[kz1000st]

Years ago Road and Track explained why a V-8 wouldn't make as many ponies as an equal sized V-12. It has to do with piston surface area being larger on more cylinders even of equal size. Of course more power means less mileage so while a 250 Ninja might ultimately outrun a CBR 250, the Ninja suffers in comparison in terms of fuel mileage.

[JR]

All very true but there are lots of varibles to look at in comparing sometimes. For instance you can have the same size liter wise in two different engines yet they perform totally different say short stroke versus long stroke. I go back to the day of the huge big long stroke engines that once the reached a good cruising speed would run at 60 MPH and get better MPG than the same size short stroke engine at the same speed. Short stroke equals more hores quicker but works more to make them. More work equal less MPG.

For instance in the late 50's Ford came out with the long stroke 292, you could almost count the revolutions of the pistons when it was idling, it had that long of a stroke. You could wind that thing to 90 MPh in second gear. Then they came out with IMO the greatest engine they ever made the 289 but if you wound it to 90 MPH in second gear you'd be praying it didn't throw a rod through the hood, just like the Chevy 283 it was short stroked. But put one of these on the line and man could you burn some rubber!

Ah those were some engines!

JR

[prodigit]

I suppose there's more to see than just adding a cylinder isn't there?
I ask because if a scooter could have been made with twin cylinders, they would have done so long time ago...

It seems you mainly find twin cylinders on heavy cruisers, touring bikes, or sportsters, that need more than what a single cylinder can offer.

Perhaps a single cylinder would create too much heat, too much torque on the chassis when ignited, so the motor vibrates back too hard when the piston is no longer under load...

Then there's probably the added cost and complexity of a motor with more than one cylinder; another reason why they won't build multi cylinders on a small scooter, that meant to be affordable.

It's logical to say that a twin cylinder engine will have more torque and power than a similar single cylinder engine; and thus use up more gasoline.
However, if a balance is found, eg: Comparing a single cylinder 150cc, with a dual 50cc (100cc), and both engines would perform about the same, what would their gas mileage be?

Basically, if their acceleration would be the same, shouldn't they have the same gas mileage too? Most surely the engine would run more smoothly, less noisy, smaller exhaust, and much more reliable too! (in case one spark plug would break, there's still a small cylinder to drive you home or to the nearest garage).

There are many benefits to dual cylinders.

I just don't know, if dual cylinder automatically means more gasoline usage. After all, you'd also have more power, better acceleration, and more smooth ride with 2 cylinders!

[wolfhound]

Honda has just released a 2 cyl. scooter and 700cc bike. The bike is being released in this country this month and has
been well recieved in Europe already. The bike is reasonably priced, I think the model is CR700x but dont hold me to
that. The scooter is not scheduled for release in this country. And doesnt Honda use a 2 cyl engine in the Silverwing
scooter?
I like the 1 cyl. cause I am cheap and look for good MPG and am satisfied with 55-60 mph!!!