Author Topic: Single Carb cb550 Video (Read 5185 times)

Lostboy Steve · « **on:** December 07, 2015, 02:25:55 PM »

Has anyone seen this on youtube? lol pretty neat idea if you were sold a bike with destroyed carbs. The manifold may even prove useful in a turbo setup if altered a bit. Leaded copper pipes if polished up might look pretty nice too.

Scott S · « **Reply #1 on:** December 07, 2015, 02:29:52 PM »

Anytime I see an SOHC4 with less than 4 carbs, I feel like someone just didn't have the cajones to get 4 carbs running right. Unless there's a turbo or F.I. involved.

Lostboy Steve · « **Reply #2 on:** December 07, 2015, 02:33:28 PM »

...and i tend to agree, especially because I did two racks of carbs on my 77 after finding a gross vacuum leak in my first set, but nontheless pretty cool.

seanbarney41 · « **Reply #3 on:** December 07, 2015, 04:30:43 PM »

It sounds like #$%*.

goldarrow · « **Reply #4 on:** December 07, 2015, 06:18:02 PM »

The other 3 carbs were sold off to fund the project???

Dimitri13 · « **Reply #5 on:** December 10, 2015, 02:49:10 AM »

Someone saw a Harley chopper side-draft carb and said "I want that!"

Neat idea, and I'm jealous of the accelerator pump.

dusterdude · « **Reply #6 on:** December 10, 2015, 04:42:56 AM »

See what?

cb650 · « **Reply #7 on:** December 10, 2015, 12:50:17 PM »

650 frame

carnivorous chicken · « **Reply #8 on:** December 10, 2015, 01:00:07 PM »

That poor #1 cylinder, I'm guessing it doesn't get much fuel.

flybox1 · « **Reply #9 on:** December 10, 2015, 02:21:02 PM »

Quote from: carnivorous chicken on December 10, 2015, 01:00:07 PM

That poor #1 cylinder, I'm guessing it doesn't get much fuel.

+1

riverfever · « **Reply #10 on:** December 10, 2015, 05:56:27 PM »

I've had farts that sounded better.

jaguar · « **Reply #11 on:** December 10, 2015, 06:43:01 PM »

I see ZERO point in set ups like this.

RevDoc · « **Reply #12 on:** December 10, 2015, 08:36:43 PM »

Quote from: carnivorous chicken on December 10, 2015, 01:00:07 PM

That poor #1 cylinder, I'm guessing it doesn't get much fuel.

That was my immediate thought as well. #1 & 2 would be lean as hell and you would have to get into all sorts of B/S jetting to get it running anywhere near decent! If that would even be possible.

Deltarider · « **Reply #13 on:** December 10, 2015, 11:41:16 PM »

Quote

That poor #1 cylinder, I'm guessing it doesn't get much fuel.

A lot of "+1" comments, so I take it someone can explain to us dumbheads why this would be the case.
Apart from the exhaust the engine seems to run quite silky.
BTW, that ram-air setup is an ideal flycatcher.

carnivorous chicken · « **Reply #14 on:** December 11, 2015, 07:34:32 AM »

Quote from: Deltarider on December 10, 2015, 11:41:16 PM

Quote
That poor #1 cylinder, I'm guessing it doesn't get much fuel.
A lot of "+1" comments, so I take it someone can explain to us dumbheads why this would be the case.
Apart from the exhaust the engine seems to run quite silky.
BTW, that ram-air setup is an ideal flycatcher.

A set up like that, with a single carb on one side of the manifold, means that the gas/air for the #1 carb has to rush by three cylinders prior to arrival, and all three are competing to suck it in too. Most manifolds that connect to four cylinders (think V-8s, or even other single carb attempts on SOHC fours) put the carb in the middle of the cylinders.

RevDoc · « **Reply #15 on:** December 11, 2015, 09:49:21 AM »

Quote from: carnivorous chicken on December 11, 2015, 07:34:32 AM

Quote from: Deltarider on December 10, 2015, 11:41:16 PM
Quote
That poor #1 cylinder, I'm guessing it doesn't get much fuel.
A lot of "+1" comments, so I take it someone can explain to us dumbheads why this would be the case.
Apart from the exhaust the engine seems to run quite silky.
BTW, that ram-air setup is an ideal flycatcher.
A set up like that, with a single carb on one side of the manifold, means that the gas/air for the #1 carb has to rush by three cylinders prior to arrival, and all three are competing to suck it in too. Most manifolds that connect to four cylinders (think V-8s, or even other single carb attempts on SOHC fours) put the carb in the middle of the cylinders.

You got to it before I did, CC. I've seen other attempts like this in industrial & marine applications and they all work poorly.

Yes, the engine may sound like it idles smoothly but try putting it under load and see what happens. Honda engineers knew what they were doing when they designed our engines with individual carbs for direct feed rather than one of these contraptions!

buffalogt750 · « **Reply #16 on:** December 11, 2015, 10:36:41 AM »

If you go on youtube and find this video the builder says it made 92 horsepower on a dyno. He probably meant 9.2 horsepower.

strynboen · « **Reply #17 on:** December 11, 2015, 10:44:31 AM »

the optimal vas 1 floate champer vho vas lined up to the 4 kaburators.. one flote/ gas valve is easyer then 4..
is it possibel to remove the 3 floats gas/ valve..and make one as a marster..and puts lines to the other bovls..to fill them..but only have one to kontrol and delevre to the rest.

.but i like the stock ..it vorks for me..after i kleaned the rust aut of my tank

curemode2002 · « **Reply #18 on:** December 11, 2015, 11:13:00 AM »

That and the carb he is using is going to be sucked dry at higher RPMs. I could see going with one or two webber carbs like the drag guys used to back in the day.

jaguar · « **Reply #19 on:** December 11, 2015, 12:24:19 PM »

Maybe at the crank....and he used a 75% loss formula

jonda500 · « **Reply #20 on:** December 11, 2015, 06:07:40 PM »

Quote from: Deltarider on December 10, 2015, 11:41:16 PM

Quote
That poor #1 cylinder, I'm guessing it doesn't get much fuel.
A lot of "+1" comments, so I take it someone can explain to us dumbheads why this would be the case.
Apart from the exhaust the engine seems to run quite silky.
BTW, that ram-air setup is an ideal flycatcher.

My personal opinion (initial startup and throttle pump aside), is that #1 would get the same air/fuel ratio as the other three cylinders.
My vacuum guages have two much longer tubes that screw into the two inner cylinder manifolds but this doesn't mean they get a lower vacuum reading than the short ones - I have checked this!

I agree that single carb looks too small for that purpose (unless it came off a 1000cc twin or something!)

John

carnivorous chicken · « **Reply #21 on:** December 11, 2015, 08:54:32 PM »

Quote from: jonda500 on December 11, 2015, 06:07:40 PM

My vacuum guages have two much longer tubes that screw into the two inner cylinder manifolds but this doesn't mean they get a lower vacuum reading than the short ones - I have checked this!

John

Completely different concept. Your vacuum gauges are measuring pull (vacuum) of the carbs, run through the same tube. Distance doesn't matter. Vacuum for #1 carb on this could be the same as #4, but that doesn't mean that it's getting the same amount of fuel. It's being siphoned off by 4, then 3, then 2, and 1 is getting what makes it that far. There's a reason you don't see SOHC fours with single carbs very often. It may sound easy (if you're lazy and can't figure out four carbs) but it's not very effective.

Deltarider · « **Reply #22 on:** December 11, 2015, 11:42:17 PM »

Quote

It's being siphoned off by 4, then 3, then 2, and 1 is getting what makes it that far.

I'm lost here. Don't they siphon by turn, alternatively? Doesn't the vacuum of 1 siphon as hard as the others? And isn't there a constant feed? What fysics is this? The way you guys put it, I can't understand how it could run at all. But it does and quite silky I must say.

seanbarney41 · « **Reply #23 on:** December 11, 2015, 11:48:10 PM »

Quote from: Deltarider on December 11, 2015, 11:42:17 PM

Quote
It's being siphoned off by 4, then 3, then 2, and 1 is getting what makes it that far.
I'm lost here. Don't they siphon by turn, alternatively? Doesn't the vacuum of 1 siphon as hard as the others? And isn't there a constant feed? What fysics is this? The way you guys put it, I can't understand how it could run at all. But it does and quite silky I must say.

hey,if you think it sounds great, go ahead and run that #$%* on your own bike then

buffalogt750 · « **Reply #24 on:** December 12, 2015, 05:27:46 AM »

Quote

It's being siphoned off by 4, then 3, then 2, and 1 is getting what makes it that far.

By that theory any intake manifold with unequal length runners can't work? So the one I have pictured here, or any 6 cylinder or V8 manifold for that matter, is total crap and will starve the cylinders farthest from the carb? The carb he uses is from a Harley Softtail so I'm sure it is big enough. I would never attempt this but the bike sounds alright to me. However the 92 horsepower he claims is certainly total BS.

Bailgang · « **Reply #25 on:** December 12, 2015, 05:39:13 AM »

Geez guys what's all the hubbub about? Somebody tries something different and everyone else takes turns bashing him? The single carb isn't for me either but I will give the guy credit for trying and I wouldn't necessarily call the guy lazy because it looks like it took some effort to build it. I see some possible issues as well but I'm not quick to assume either, other than a smoother idle I would highly doubt any performance gains in fact I imagine the builders intent was more for the "look" value than anything else. Yeah I think the 92 hp claim is absolute BS too.

If you want to see some crazy DIY carb setups then you should check out some Goldwing sites, going to a single carb setup is popular with GL owners mainly because rebuild kits can be pricey for them and or owners really are too lazy to figure out multicarb setups, some conversions are well done while others are just plain back yard engineering. The most amusing I've seen was where the owner made his own intake manifold using plastic PVC pipe.

Nope that's not for me either, I instead spent the money to get the correct kits for the carbs on my GL1100.

carnivorous chicken · « **Reply #26 on:** December 12, 2015, 07:33:49 AM »

That's the configuration I alluded to in my post as functional -- a single carb in the middle of the cylinders. Compare the bends in that manifold to the one on that bike. Sharp, 90-degree bends? Small diameter pipe with no flare on the intake? I'm not going to belabor the point all day or argue with people -- some people like this, some don't, and I don't really care. It just doesn't look functional to me and, again, there is a reason why there aren't a lot of SOHC4 conversions to single carbs.

Deltarider · « **Reply #27 on:** December 14, 2015, 11:51:35 AM »

As far as I'm concerned, there's no debate whether that setup with one carb (probably ment as a joke*) will work well or even better than the original 4 carbs (it will not). I just question all this echoing of members here that #1 carbs must run awfully lean whereas no one so far can produce convincing proof. Then, when I present myself as a dumbhead that still doesn't get it, some even loose their temper. That tells ya, doesn't it? Don't get me wrong: I'm open for evidence based reasoning but not for stupid remarks from folks that can't distinguish the sound of a nice running engine from the not so nice sound of the exhaust.
* anyway that's how I see it.

jonda500 · « **Reply #28 on:** December 14, 2015, 03:07:42 PM »

Quote from: Deltarider on December 14, 2015, 11:51:35 AM

As far as I'm concerned, there's no debate if that setup with one carb (probably ment as a joke*) will work well or even better than the original 4 carbs (it will not). I just question all this echoing of members here that #1 carbs must run awfully lean whereas no one so far can produce convincing proof. Then when I present myself as a dumbhead that still doesn't get it, some even loose their temper. That tells ya, doesn't it? Make no mistake: I'm open for evidence based reasoning but not for stupid remarks from folks that can't distinguish the sound of a nice running engine from the not so nice sound of the exhaust.
* anyway that's how I see it.

+1!
I think it sounds great and I commend the creater for trying something different! I hope an air filter is added when it's ridden!
John

BPellerine · « **Reply #29 on:** December 14, 2015, 03:27:00 PM »

do a search for the build nelsinore ,the guy made a single carb setup for cb 750 that worked.bill

Scott S · « **Reply #30 on:** December 14, 2015, 05:55:25 PM »

I think that 750 had dual carbs.

Stev-o · « **Reply #31 on:** December 14, 2015, 06:50:39 PM »

Quote from: Scott S on December 14, 2015, 05:55:25 PM

I think that 750 had dual carbs.

No Scott, it was a single Mikuni....

http://forums.sohc4.net/index.php?topic=116272.0

Don R · « **Reply #32 on:** December 14, 2015, 07:23:53 PM »

Take a look at the 6 cylinder intake, the center runners are large, the next two get smaller and the two end ones are the smallest. This is an effort to equalize the flow. Math isn't my strong suit but assume 8,000 rpm, each cylinder needs air/fuel every other revolution that's 4,000 pulses per minute or 1,000 pulses per cylinder per minute. That's 16.6 pulses per second, There will be a steady pull but my guess is the closest cylinder will be the big dog. if the intake main tube stepped up in size toward the carb that could help some. Will it work? Yes. Will it win many races? Probably not.
There are also reversion pulses going backwards when the cam is in overlap but that's another story.

jonda500 · « **Reply #33 on:** December 14, 2015, 08:28:29 PM »

Still no-one seems able to expain it...
Not meaning to upset ppl, but where exactly is #1 getting the extra air from to make it run leaner than #4?

I have seen car manifolds with equal diameter but unequal length inlet tracts...
John

Don R · « **Reply #34 on:** December 14, 2015, 09:31:10 PM »

Performance intake designers go to great lengths to make the runners the same for good performance. There's an entire industry devoted to it. Some engines are designed to a price point and corners are cut. They still run.

On my big block, even with a high dollar intake I still have 4 different size jets on the 4 barrel carb to get the same fuel mix to all of the cylinders. Cylinders 5 and 7 are consecutive in the firing order of most V8's (18436572) and are also on the same corner of the intake. Cylinder 7 is always leaner because 5 steals the flow before 7 can get it. To solve this we make a new cam to swap 4 and 7 in the firing order. When 5 and 7 aren't fighting for the fuel it makes more power and cylinder 7 has fewer problems due to running lean.

I can't explain the science any better but it's a proven fact.

kghost · « **Reply #35 on:** December 14, 2015, 09:51:27 PM »

Quote from: jonda500 on December 14, 2015, 08:28:29 PM

Still no-one seems able to expain it...
Not meaning to upset ppl, but where exactly is #1 getting the extra air from to make it run leaner than #4?

I have seen car manifolds with equal diameter but unequal length inlet tracts...
John

How familiar are you with Fluid Mechanics (static or Dynamic)?

Scott S · « **Reply #36 on:** December 15, 2015, 09:21:10 AM »

Quote from: Stev-o on December 14, 2015, 06:50:39 PM

Quote from: Scott S on December 14, 2015, 05:55:25 PM
I think that 750 had dual carbs.

No Scott, it was a single Mikuni....

http://forums.sohc4.net/index.php?topic=116272.0

Ok, not the same bike I was thinking of.

njclimber · « **Reply #37 on:** December 15, 2015, 06:09:37 PM »

I bet it has nothing under load.

Redline it · « **Reply #38 on:** December 16, 2015, 11:49:16 AM »

Quote from: carnivorous chicken on December 10, 2015, 01:00:07 PM

That poor #1 cylinder, I'm guessing it doesn't get much fuel.

I'd have to consider one thing, how much less, the #1 is getting, but you could always implement a volume regulated stream by a little bit more of using the same length of tube. #4 would have a loop, that'd be bad ass, polished. Or use the 4 original old rebuilt, and calibrated carburetors that give you can of worms fuel delivery 24 7s. Or the 4 will work great one day and next they give you trouble. I have a little 400f I could spend a little time and make it show room condition, but I ride it instead. Mikuni 38mm fat jetted, would do the job just fine.

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Author Topic: Single Carb cb550 Video (Read 5185 times)