upgrading to carburetion

[sho'noff]

I know there are some three cylinder motorcycles engines out there with 1 carburetor per cylinder.
I would like to see a sho with 2 sets of these carbs linked to either bank of cylinders. using a carb cfm calculator I entered 3200 cc's at 6800 rpm and got a result of 318.906 cfm.
the yamaha xs850 4 stroke cfm would be 105.887 then times that by 2 equals 211.774, so a larger set of carbs would be nessicary to accomplish this.
anyone tried this? I don't know if it is possible although I saw a vw rabbit with some carbs.

 

[SHOmethewayhome]

I know there are some three cylinder motorcycles engines out there with 1 carburetor per cylinder.
I would like to see a sho with 2 sets of these carbs linked to either bank of cylinders. using a carb cfm calculator I entered 3200 cc's at 6800 rpm and got a result of 318.906 cfm.
the yamaha xs850 4 stroke cfm would be 105.887 then times that by 2 equals 211.774, so a larger set of carbs would be nessicary to accomplish this.
anyone tried this? I don't know if it is possible although I saw a vw rabbit with some carbs.

interesting project, but the stock intake already flows pretty damn well.

what would you be gaining by swapping over to individual carburetors?

also, at that point, why not custom fab an intake to run 3 sets of webers?

 

[yamahaSHO]

Are you really trying to do ITB's, or do you really want controlled fuel leaks?

 

[sho'noff]

just an idea at this point, alot of motorcycles make much more horsepower per cc than any car.
For example a kawasaki gpz750 with 2 valves per cylinder, dual overhead cams 4 cylinder makes roughly 86 horsepower at 9500 rpm.
739 ccs and 86 horsepower is more than 1 horsepower per 10 cc's 1995 taurus sho 3200 cc's 220 horsepower is less than 1 horsepower per 10 cc's.
I am sure alot of it has to do with winding a little 4 cylinder engine to 9500 rpm, but the individual carburetors and very long equal length pipes help.
my kz750 has a clean air system that lets air into the exhaust with reed valves. I took the main hose off for the system with it idling and the velocity of the exhaust through the pipes created a lot of vacuum.
If there was a way to put very long equal length headers on the sho I am sure there would be a great power output increase.

 

[yamahaSHO]

Your logic is severely flawed... Stop comparing motorcycle engines to car engines. It's not the carbs that make the power (and they don't really use them anymore anyway).

 

[sho'noff]

Your logic is severely flawed... Stop comparing motorcycle engines to car engines. It's not the carbs that make the power (and they don't really use them anymore anyway).

com on, it is a yamaha

 

[yamahaSHO]

So.................. ....... ............ ...

 

[sho'noff]

actually alot of motorcycles use carbs even still, because they don't use conventional spark plug wires! they would eventually burn the ecu.

 

[sho'noff]

actually 220 horsepower in a front wheel drive scares me.

 

[yamahaSHO]

What bikes are you looking at?

Not sure how you're going to "burn the ecu" either.

 

[sho'noff]

interesting project, but the stock intake already flows pretty damn well.

what would you be gaining by swapping over to individual carburetors?

also, at that point, why not custom fab an intake to run 3 sets of webers?

webers? vw carbs? that is awesome.

 

[Shovert]

Here is one with 4 barrel carb.
http://www.supermotors.net/getfile/601517/fullsize/carb.-sho-engine.jpg
As far as motorcycle carbs. Been done. Got a link with Honda s2000 with carbs. Maurice

 

[yamahaSHO]

I'm willing to bet the S2000 had ITB's and not carbs.

 

[SHOtime2511]

ITB would be kind of cool if for some reason you are dead set on N/A performance.
Carbs would probably give you a net loss.

 

[intimdatr]

Most bikes since 2006 have gone to Fuel Injection and will never look back. The biggest fail point of bikes is the winter months and fuel stagnation.

Carbs are a cool idea but the amount of work you are going to have to to make this work is going to be long and get very expensive. And likely you are going to see a loss in power in the very day world on top of seeing a possible drop in fuel economy.

The world has gone to fuel injection for a reason. Id stay with it. And gauging by the other threads youve started you need to work on you maintenance before you start crazy stuff like this.

 

[sho'noff]

yeah, I guess it wouldn't really be an upgrade as I said in the title, thanks

 

[Racer X]

The biggest fail point of bikes is the winter months and fuel stagnation.

Tell me about it...

 

[intimdatr]

Tell me about it...

My dad lost a Honda Saber that way.

However we did find a Honda Vf500 Interceptor for 300 bucks and cleaned the carbs 3 times and put in all new jets and the thing screams. I love the bike!

 

[sho'noff]

I found one of those speed signs that shows how fast you are going, it seems revving the motorcycle engine throws it way off.

 

[rubydist]

anyone who has worked on multiple carb setups will tell you that it is a royal pita to get them balanced. the complexity of balancing them goes up with the square of the number of carbs, so 6 carbs is 36 times more difficult to tune properly than 1 carb.

you have way more potential to make things better with the fuel injection and tuning.