Single Or Dual Carbs

[Matt_E]

A carb is only good for so much airflow....it is supposed to deliver 1:14.7 across the entire flowrange.
But I suspect that at high air velocities the metering gets funky....the fuel passage cannot flow any more fuel(it leans out).

 

[waxhead]

I would think that a decent carb manafactuer would make a carb that can flow more fuel than it can air so that they dont have to people complaining about stuck engines
It would be safer from a marketing point to view

 

[ArtMaybee]

Once a carb has been modded to flow more air it can then outpace the stock fuel delivery capacity of the carb at WOT.

Nobody can give Mikuni troubles about this because normally the problems come with Running WOT on a single setup with a modded carb. These are no longer TRULY mikuni designs because they have been "re-engineered"

I'd have a hard time believing that a STOCK 44SBN could flow enough air that it couldn't be richened up to run WOT all day long. It wouldn't flow nearly as much air as a modded SBN so it would also be making less power and be turning less RPMs. BUT... It should be able to run WOT.

 

[WaveDemon]

A carb is only good for so much airflow....it is supposed to deliver 1:14.7 across the entire flowrange.
But I suspect that at high air velocities the metering gets funky....the fuel passage cannot flow any more fuel(it leans out).

the size of the throat should restrict airflow before the carb can't meter enough fuel to keep up with demand.

 

[WaveDemon]

Once a carb has been modded to flow more air it can then outpace the stock fuel delivery capacity of the carb at WOT.

Nobody can give Mikuni troubles about this because normally the problems come with Running WOT on a single setup with a modded carb. These are no longer TRULY mikuni designs because they have been "re-engineered"

I'd have a hard time believing that a STOCK 44SBN could flow enough air that it couldn't be richened up to run WOT all day long. It wouldn't flow nearly as much air as a modded SBN so it would also be making less power and be turning less RPMs. BUT... It should be able to run WOT.

don't the aftermarket companies open up the fuel passages to match? I'm pretty sure I've read somewhere that they do.

 

[Matt_E]

the size of the throat should restrict airflow before the carb can't meter enough fuel to keep up with demand.

Hey, I'm just guessing.:biggrin:

 

[ArtMaybee]

Im sure they open them up.
But obviously there are still some issues with fuel delivery.

If your airflow is restricted, you will not be able to run the RPMs no matter how much displacement your motor has. More displacement, less airflow, adds up to lower RPMs before the thing runs out of breath.

If you can't run WOT with a carb on a motor (especially with the main jet removed), there are serious fuel delivery problems. Now, most people KNOW these problems exist with modded single carb setups and stay off WOT as much as possible.

 

[waxhead]

wow not isnt all this great
arent single carbs awesome

 

[SuperJETT]

Im sure they open them up.

Novi doesn't, the fuel takes a much longer path around the jet cover than stock.

 

[T-bone]

I'd have a hard time believing that a STOCK 44SBN could flow enough air that it couldn't be richened up to run WOT all day long. It wouldn't flow nearly as much air as a modded SBN so it would also be making less power and be turning less RPMs. BUT... It should be able to run WOT.

it defentlly flows enough fuel and air, my blaster gets ridden at WO all day long, single 44 carb.

 

[WaveDemon]

wow not isnt all this great
arent single carbs awesome

aren't you the one who just bought a wetjet manifold...

 

[T-bone]

dont dis the wetjet manifold, its the way to go on the 61X

 

[waxhead]

yes i am but its on a 61x that was designed for the single carb
the 62t is the one every one else is talking about
No one is interested in a single carb on a 61x as they cant sell a manifold for it so there is no reason to push it

 

[ArtMaybee]

it defentlly flows enough fuel and air, my blaster gets ridden at WO all day long, single 44 carb.

Yeah... but is your 44 a STOCK carb or is an aftermarket or modded carb?
Becauase usually the stock carbs aren't the ones with problems running WOT.
I was only referring to modded carbs that will run lean at WOT.

 

[T-bone]

heres a nice looking single carb. 49mm

 

[Takeastand SJ]

What kind of porting do you have............ I am not saying it impossible, just not adviseable............ I ran a single for a year and loved it, but swapped to dual 44's, even better now......... I could go back to a single tomorrow with no hesitation.

Who said anything about arguing? this just a good debate.
:Banane01: :Banane01: :Banane01:

I don't have any porting now, just head, pipe, and MSD. In a few months I'm putting in a 760 with some minor porting and maybe stroked we'll see. I'm not going to change the carb, I rode with a guy that had a ported stroker motor a few months ago with the 48 power bomb and he has had no problems. Again, you can't go race with a single carb but short full throttle runs are no problem.

 

[surfgy45]

i have to jump in and say, this is a very informative thread!! thanks fellas. too bad i just dont understand quite everything yet with your ratios and fuel to gas what nots. but i like it!

deserves a dancing banana... :Banane01:

personally, i want to switch to dual 44's over my single wamiltons 44 set up. ported, piped, whole shabang bolt ons...the single lacked the ability to keep up with fuel delivery on short WOT (and i mean pinning throttle after a brief gain to plain out on water) motor would just die out. but im also under the impression that a well set up dual 44 will give me better low response/hit, which im after.

 

[yamaslut]

you will love dual 44's after a single setup... I gained much bottom

i have to jump in and say, this is a very informative thread!! thanks fellas. too bad i just dont understand quite everything yet with your ratios and fuel to gas what nots. but i like it!

deserves a dancing banana... :Banane01:

personally, i want to switch to dual 44's over my single wamiltons 44 set up. ported, piped, whole shabang bolt ons...the single lacked the ability to keep up with fuel delivery on short WOT (and i mean pinning throttle after a brief gain to plain out on water) motor would just die out. but im also under the impression that a well set up dual 44 will give me better low response/hit, which im after.

 

[Idok]

i have to jump in and say, this is a very informative thread!! thanks fellas. too bad i just dont understand quite everything yet with your ratios and fuel to gas what nots. but i like it!

deserves a dancing banana... :Banane01:

personally, i want to switch to dual 44's over my single wamiltons 44 set up. ported, piped, whole shabang bolt ons...the single lacked the ability to keep up with fuel delivery on short WOT (and i mean pinning throttle after a brief gain to plain out on water) motor would just die out. but im also under the impression that a well set up dual 44 will give me better low response/hit, which im after.

thats a tuning issue.......if it bogs out its probably a little fat on the highs, but if it briefly hesitates, then rips its a little lean...

 

[surfgy45]

thats a tuning issue.......if it bogs out its probably a little fat on the highs, but if it briefly hesitates, then rips its a little lean...

napes, i had it tuned by JetWorks in their in-house tank along with the rebuild