Cb750 Dual Carb Intake Design

xb33bsa said:
the difference is a motorcycle engine is in an extreme state of high perf tune compared to the examples you refer to
these old jap motors are putting out close to 100 hp to the liter, the 2 valve ones, the 4 valvers are all higher than that
you cannot get that without really efficient breathing
if it was just as good to have less than one carb per cylinder the mfg's would have done it in the first place fer fucks sakes
think of the money they would have saved,you dont think they researched it ? hell yes they did
for the average joe or jill,it really borders on idiotic to not run the oem carb setup and airbox
Click to expand...

Your posts drive me crazy. You obviously have good knowledge of engine performance, obviously more than I. You can offer good info, but then you talk down to people because they don't share the same taste in motorcycles as you. It seems that you hold optimum engine performance paramount to everything else on every motorcycle. If I were building a race bike, I would agree with you. Its obvious though, that I'm not. I don't think it I is idiotic to ditch the stock air box and carbs at all. I built an affordable stripped down bike to cruise back mountain roads. I want a bike that rides the streets well, and looks great doing it. I think that twin carbs poking out from under the tank looks awesome, and runs better without an air box compared to the stock cv's. Plus I can build the kit for less than half the price of a set of FCR's for example. I'd bet that a lot of cxman's customers buy for the same reason even though that's not his purpose for building the kits. I see most 750 dual carb kits on hardtail bobbers with no front brakes, and that's ok with me. I know that I'm not alone in this. Companies like Steel Bent Customs, Café Racer Dreams and Wrench Monkees build bikes that probably drive you crazy. They are not pure performance driven machines, but I like them. I think they put out a good affordable product, and I bet they function well enough that their customers are more than happy. They build bike for a target market, just like the big car companies. We can't all drive a porsche. I suggest that anyone reading this should do a search for "steel bent customs" and read the thread where guys here are bashing SBC. The company owner, Michael Mundy came and posted a very good response like a stand up guy.

One day I hope to build bikes to the caliber of Michael Woolaway, but I know its a longshot even for a dreamer like me. ;D
 
you go for it nick the world is big enough for all of us and without allowing for dreamers and tinkers the world would be a lot sorrier

it constantly amazes me that some people dont apply the thought that my bike may represent freedom of speech to me

and that if it is mine and i love it there should be some respect or at least courtesy afforded to that expression

even if it is not what others would choose

and if i expect that respect i have to pay it on down the line and respect others even if the path they choose is not mine
 
cxman said:
you go for it nick the world is big enough for all of us and without allowing for dreamers and tinkers the world would be a lot sorrier

it constantly amazes me that some people dont apply the thought that my bike may represent freedom of speech to me

and that if it is mine and i love it there should be some respect or at least courtesy afforded to that expression

even if it is not what others would choose

and if i expect that respect i have to pay it on down the line and respect others even if the path they choose is not mine
Click to expand...


Thank you. It is that point of view that makes these forms valuable for us all.
 
ncologerojr said:
Your posts drive me crazy. You obviously have good knowledge of engine performance, obviously more than I. You can offer good info, but then you talk down to people because they don't share the same taste in motorcycles as you. It seems that you hold optimum engine performance paramount to everything else on every motorcycle. If I were building a race bike, I would agree with you. Its obvious though, that I'm not. I don't think it I is idiotic to ditch the stock air box and carbs at all. I built an affordable stripped down bike to cruise back mountain roads. I want a bike that rides the streets well, and looks great doing it. I think that twin carbs poking out from under the tank looks awesome, and runs better without an air box compared to the stock cv's. Plus I can build the kit for less than half the price of a set of FCR's for example. I'd bet that a lot of cxman's customers buy for the same reason even though that's not his purpose for building the kits. I see most 750 dual carb kits on hardtail bobbers with no front brakes, and that's ok with me. I know that I'm not alone in this. Companies like Steel Bent Customs, Café Racer Dreams and Wrench Monkees build bikes that probably drive you crazy. They are not pure performance driven machines, but I like them. I think they put out a good affordable product, and I bet they function well enough that their customers are more than happy. They build bike for a target market, just like the big car companies. We can't all drive a porsche. I suggest that anyone reading this should do a search for "steel bent customs" and read the thread where guys here are bashing SBC. The company owner, Michael Mundy came and posted a very good response like a stand up guy.

One day I hope to build bikes to the caliber of Michael Woolaway, but I know its a longshot even for a dreamer like me. ;D
Click to expand...

Well some others think that downgrading performance in the name of looks is stupid.
Some think there are far to many people playing a game of dress up with their motorcycles and far to many people selling junk to unsuspecting people.

$600 is crazy town for two basic off the shelf carbs and a pair of manifolds.
Even more so when the principle is flawed,t he execution is poor and the PR is junk.
I want to see proof that they run at least as good as stock, better yet how do they run when compared to the many other options in around the same price point?

Funny part is all this search to "make it your own" or "expressing ones self" all by making a bike work less as a bike, and just repeating other people's bad ideas.

If "runs well enough" is the benchmark then how long to "looks like it could run" is fine?
I'm always amazed by the number of bikes people fawn over don't even run!

Posts might drive you crazy, but you can't have sugar and roses all the time.
Sure some may have the knowledge and such you seek, but they might not be willing to help go down wasteful paths.
 
surffly said:
Well some others think that downgrading performance in the name of looks is stupid.
Some think there are far to many people playing a game of dress up with their motorcycles and far to many people selling junk to unsuspecting people.

$600 is crazy town for two basic off the shelf carbs and a pair of manifolds.
Even more so when the principle is flawed,t he execution is poor and the PR is junk.
I want to see proof that they run at least as good as stock, better yet how do they run when compared to the many other options in around the same price point?

Funny part is all this search to "make it your own" or "expressing ones self" all by making a bike work less as a bike, and just repeating other people's bad ideas.

If "runs well enough" is the benchmark then how long to "looks like it could run" is fine?
I'm always amazed by the number of bikes people fawn over don't even run!

Posts might drive you crazy, but you can't have sugar and roses all the time.
Sure some may have the knowledge and such you seek, but they might not be willing to help go down wasteful paths.
Click to expand...

Why does what other people do to their bikes bother you so much? Do you hate choppers? I would never ride one, but I appreciate the fab work that goes into a lot of them. On the other hand do you like race prepped moto gp bikes? Those would be amazing to ride...on a track.

I wouldn't want to ride around town everyday on a chopper or a race prepped bike.

So if all we look for is function/performance and not styling, why not just buy a modern bike and call it a day?

Some will say that it's a cool challenge making an old bike perform better, and I agree. But, I also think it's a cool challenge to bend, cut and weld to make and old boring bike look cool.

Isn't like telling a painter to just buy a camera?
 
nick arguing with someone like this is fruitless they know everything
 
surffly said:
Well some others think that downgrading performance in the name of looks is stupid.
Some think there are far to many people playing a game of dress up with their motorcycles and far to many people selling junk to unsuspecting people.

$600 is crazy town for two basic off the shelf carbs and a pair of manifolds.
Even more so when the principle is flawed,t he execution is poor and the PR is junk.
I want to see proof that they run at least as good as stock, better yet how do they run when compared to the many other options in around the same price point?
Click to expand...
Buy a set and put it on a dyno. Prove it's crap. You saying it's crap is worthless. You have shown nothing to prove you're right. The information is out there- and lots of it. You haven't looked. It's obvious what you don't know far outweighs what you do. Even the breadth of proven experience of certain people you are ridiculing and arguing with is unknown to you. Do the research and publish the results. It's obviously beyond your scope. You put on a great show, though.
 
deviant said:
Buy a set and put it on a dyno. Prove it's crap. You saying it's crap is worthless. You have shown nothing to prove you're right. The information is out there- and lots of it. You haven't looked. It's obvious what you don't know far outweighs what you do. Even the breadth of proven experience of certain people you are ridiculing and arguing with is unknown to you. Do the research and publish the results. It's obviously beyond your scope. You put on a great show, though.
Click to expand...

I'm not the guy selling the product and just talking the talk.
Would think the person selling his amazing carbs would want to show how good they are to all the dummies like me....
 
cxman said:
nick arguing with someone like this is fruitless they know everything
Click to expand...

Way to be confident in your product. So a few questions and you tuck tail me hide?

Never claimed to know everything.
Do know a good running engine and how to tune. Also have run a fair many "alternative" carbs, albeit on a sohc.
Do have questions about the idea, and question your product.

But so far all I hear about it is "it looks cool" or "it's my expression "
Tells me it is little more then a fashion item and no other thought went into it.

All ears to see this "research" "testing" and what not.
I've seen it for other carbs.

And as for this vastly experienced group that is selling, or just talking about these set ups...it's the internet....so no one knows what you know until you tell them. Haven't hear that this guy selling these kits now has some amazing history. Not that it's needed. Just if you are going to sell something legitimizing yourself to the people buying is nice . Even more so now with so many people making the jump to the bandwagon...

To me the look comes at the cost of performance.
Prove me wrong. Let's see a back to back dyno run.

Why is that such a scary request?
Why is it greeted as a heartless attack? Was that never something you thought you would be asked?
 
Why so confrontational? I can see wanting to see data (in god we trust, all others...) but screaming generally gets poor results, just ask my kids. Neighbors' kids, too.
 
Well I had asked, in this thread and others.
Was ignored.

And now I have been brushed off and been told I know nothing and should shut up..
 
surffly said:
And now I have been brushed off and been told I know nothing and should shut up..
Click to expand...

You chimed in calling someone's product crap without any evidence, or reasoning. The only explanation you provided is that someone can go out and buy smoothbores, cr's etc. You bitch that there is no evidence, but you haven't given any either.

If I was making the product, I wouldn't pander to you either. If you don't like it, don't buy it.
 
Since we're supposed to be talking about carbs, I have another question.

Would four vm34's be way too big for a dohc cb750?
 
ncologerojr said:
You chimed in calling someone's product crap without any evidence, or reasoning. The only explanation you provided is that someone can go out and buy smoothbores, cr's etc. You bitch that there is no evidence, but you haven't given any either.

If I was making the product, I wouldn't pander to you either. If you don't like it, don't buy it.
Click to expand...

I came in saying that it was not a new idea.
Latter I did say the product was crap. Over priced and in the pictures doesn't look built wells
Surely doesn't integrate the carbs well.
Actually the carbs aren't the product, just the manifolds.

If someone is going to try and sell a product it is their job to show what it does, how it works and why people should buy it.
I have questioned the sizing, flow, construction along with the basic idea.
I don't need to prove anything, how can I prove a negative? Have stated that I have worked with and seen results from other fueling options, why should I not see the results of these?
 
ncologerojr said:
Since we're supposed to be talking about carbs, I have another question.

Would four vm34's be way too big for a dohc cb750?
Click to expand...

I assume stock?
Yes, even if you could physically fit them.
There are many 34mm carbs out there, why the preoccupation with the VMs?

Actually while we are on the subject upgrading carbs on a cb750 is kind of a waste.
They are not the weak link, the flow through the head is in the sohc, money spent on the bottleneck is much better spent, if performance is the goal.
But alas, you can't see porting in a parking lot.
 
surffly said:
I assume stock?
Yes, even if you could physically fit them.
There are many 34mm carbs out there, why the preoccupation with the VMs?

Actually while we are on the subject upgrading carbs on a cb750 is kind of a waste.
They are not the weak link, the flow through the head is in the sohc, money spent on the bottleneck is much better spent, if performance is the goal.
But alas, you can't see porting in a parking lot.
Click to expand...

The flow through the head is in the sohc?

I was asking because there is a set of four vm34's on eBay for a good price. I would buy them and try my dual carb set up. If it worked I would just sell the spare two carbs, if not I would run the four.

Although I was pretty sure four vm34s would be too much.
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom