Carb suggestions???

[SLM]

Without pictures to prove you actually have such a project, we are wasting time on your hypothetical questions. If you actually have such a project, then you would be asking questions like how to convert from 4 carbs to one.

Show me the engine.

Seriously, if you want help, stop being an *** and actually show us that you have some idea about what you want us to help you with.
I wish some people could 3D print common hand tools and common sense,
390 CFM might be close if you need an off the shelf carb, but, honestly, I would think a genius like yourself could just print a manifold with a carb already installed. Then you could show us a better way to do it.
Have a nice day.

how am I the one thats being the ***??(whatever that is)
Im literally just asking questions and you starte mocking and saying im lying bout my project, im really just trying to learn, you got mad for no reason.
I hope you realize you r being the ******* right now by just assuming im lying, like wtf did i ever do to u? calm down and lets talk engines man thats what this is about, go let out your loneliness somewhere else.
Also even though it IS actually possible to print a carb and a manifold in one piece (if you knew anything bout 3d printing youd kw its posssible) its just too much work designing the carb so that the enturi and all the passages work efficiently, AND, I never said i anything about printing a manifold already installed on a carb, thats ridiculous , ON TOP OF THAT, i never said i kw better,ispecificlly said I dont, you just keep twisting my words man.

Actually, that math was wrong...

indeed it was, maybe go back to college to learn about it (if u ever went in the first place)

 

[SLM]

you kw what, f u, im actually gonna print that manifold with the carb on, teach your unmannered know it all a lesson, gimme till thurday nd ill show u

 

[Grizzlymi]

I'm curious how this 4 carb manifold is going to work. You asked questions about the carb, which I have no problem with. Teach us all how this is going to work out. I'm new to 3d printing, so hope it all works out. Asking about what carb works on 750 without figuring out the manifold is what I want to know. Hope it all works out and can't wait to see what you come up with. Pictures would help a ton.

 

[Grizzlymi]

And just for the record, people come on here all the time looking for advice., and then get snarky at the replys. Tons of great info on here from many people with a ton of knowledge. So just get used to it and have a sense of humor. Looking forward to that 3d printed manifold.

 

[SLM]

I'm curious how this 4 carb manifold is going to work. You asked questions about the carb, which I have no problem with. Teach us all how this is going to work out. I'm new to 3d printing, so hope it all works out. Asking about what carb works on 750 without figuring out the manifold is what I want to know. Hope it all works out and can't wait to see what you come up with. Pictures would help a ton.

I thought about using a two carb setup like the murray´s twin carb kit, but that kit is too expensive so i thought id 3d print my own manifold, there are heat resistant filaments out there that can handle more than enough the heat the engine will be making, and lots of people have done this before, my initial plan was to just find two carburators and make two manifolds so that each carb feeds two cilinders, I have the manifold figured out, i just havent made it yet because i would need to custom make it so it fits whatever carb i put on, but now that im going to be 3d printing it that wont be much of a problem.
I will be posting pictures, as soon as i find them lol

And just for the record, people come on here all the time looking for advice., and then get snarky at the replys. Tons of great info on here from many people with a ton of knowledge. So just get used to it and have a sense of humor. Looking forward to that 3d printed manifold.

ya i kw i kw, but one thing is calling out someone for not knowing something, another thing is just straight up putting them down, some people get very brave behind a computer screen, those people tend to have very low self steem and thats why they take it out on someone whom they know will have no consequences if they do, I´ve been here for a couple years, ill admit ive been on and off and ive switche accounts cause i forget the passwords and ive gotten comments calling me out for not knowing, jokes, but nevera useless answer thats just someone taking it out, I do hope i get used to it, but it just bugs me that people think they can act like that hiding behind a screen and go off feeling the same

 

[SLM]

as for those pictures, theres reallly not much to see, cuz i dont wanna mount the engine yet untill i know the engine runs and well, its a cb750c engine, previous owner said the engine was good but i just wanted to check how it ran first. I will have the manifold by thursday, mark my words yall, thank you for actually helping and contributing to the project. thanks and have agood day man

 

[Master Hack]

everyone calmdown!
SLM, l have a particular interest in your project, see l have one very similar.

what you are proposing can, has,and will be done. Purdy fun toy when complere.
Your approach is a good one. I want to know if mine runs before committing all that work. Thats only smart. There are about 15million things that need to be done on a project like this. Yer on step #145 already. Yes it is important, but ya need to back up and start at #1. If it has no carb, what else is missing? Ya gonna buy a carb, (no such thing as a cheap option) to put on an engine of unknown condition? lf yer gonna just ask others to tell ya how to do it cuz yer "busy" then this is a doomed project. You'll get "info" thats all over the spectrum.
Ya need to get a battery and see if it turns over and has compression. Then ya can decide if its worth the time, money and effort.

 

[panchothedog]

SLM, your idea of printing a manifold while it's probably possible, did you ever stop and think about the engineers that actually designed and built the engine. They decided that 4 separate carbs was the best way to feed fuel and air into the engine. Your chances of fabricating something that even comes close to performing half as good are a thousand to one. As far as printing a carburater, have you ever actually taken one apart? The tiny orficces, the needle and seat mechanism, float, springs, butterfly or throttle slide. I don't care how much you know about computers and 3-D printing, you are not going to print a WORKING carburater. BTW, I am probably older than your Grandfather and never graduated from high school. But I am smart enough to recognize an arrogant youngster who is in way over his head. If you want it to run properly, put the carbs that the factory put on it.

 

[Darren]

I wrote a similar post then deleted it, I think ebay may have a 4 carb setup, I wish young posters wouldn't abbreviate words 'thumb text' These posts are around for a long time and can help fellow enthusiasts. High revving engines require fuel injection or a carb for each cylinder. There's a guy 3d printing a motorbike manifold on youtube, He seems to have cracked it, but also admits vibration could just crack the plastic.

 

[SLM]

everyone calmdown!
SLM, l have a particular interest in your project, see l have one very similar.
View attachment 152523 View attachment 152524
what you are proposing can, has,and will be done. Purdy fun toy when complere.
Your approach is a good one. I want to know if mine runs before committing all that work. Thats only smart. There are about 15million things that need to be done on a project like this. Yer on step #145 already. Yes it is important, but ya need to back up and start at #1. If it has no carb, what else is missing? Ya gonna buy a carb, (no such thing as a cheap option) to put on an engine of unknown condition? lf yer gonna just ask others to tell ya how to do it cuz yer "busy" then this is a doomed project. You'll get "info" thats all over the spectrum.
Ya need to get a battery and see if it turns over and has compression. Then ya can decide if its worth the time, money and effort.

Hi MasterHack, yes your right, thats where I should start, however the previous owner said he tore down the engine imslef and said everything was in good order, as for the carb i meant something cheap for a carburator, obviously i understand i cant get a carb for 15 bucks, the only reason i decided to go the printed routeis customization, my own curiosity, and to prove sparky wrong tbh. nothing else is missing, and im not asking cuz im busy, im asking cuz i wasnt able to find anything on the internet.
I already ahve a battery on order and im just waiting for it to come, along with all the other electronic bits.

SLM, your idea of printing a manifold while it's probably possible, did you ever stop and think about the engineers that actually designed and built the engine. They decided that 4 separate carbs was the best way to feed fuel and air into the engine. Your chances of fabricating something that even comes close to performing half as good are a thousand to one. As far as printing a carburater, have you ever actually taken one apart? The tiny orficces, the needle and seat mechanism, float, springs, butterfly or throttle slide. I don't care how much you know about computers and 3-D printing, you are not going to print a WORKING carburater. BTW, I am probably older than your Grandfather and never graduated from high school. But I am smart enough to recognize an arrogant youngster who is in way over his head. If you want it to run properly, put the carbs that the factory put on it.

Hi pancho, yes yes, i am well aware, however, i dont know how familiar you are with 3d printing but 1) the engine originally had four carbs so the only "manifold" they had would be the rubber boot that holds the carbs. 2) I am basing this design off of the Murray´s carbs dual carb kit for this bike, and the dimensions I was able to find on the internet or from other 3d models, however if the 3d printed carb works (i KNOW it will work id dont know how well it will though, if evven well enough) if the printed carb works i will print four of them and go the stock route.
yes i have taken one apart, never s super sofisticated one though, mostly just go karts and dirtbike carbs and the orifices are not a problem at all, like i said before, i do not know how familiar you are with 3d printing but small and intricate passages and shapes is what 3d printing excels at so those wont be a problem, as for the needles and similar, i will be using those from a carb rebuild kit so i know i wont get the wrong ones or wrong sizes, and not to be a dickhead and know it all but, actually, it IS possible and in fct has been done, i will admit not on this scale, but thats why we are here, to discuss new ideas and madman projects, i thought this was a DIY community, why would you not want to know if its possible to make your own carburators? i think its a great experiment that could open a whole new path for the DIY community, imagine just being able to switch venturi sizez, float bowl depths, manifold lengths or carb dimensions in less than a day? instead of having to buy a different carb everytime one doesnt fit, all you would have to buy is jets, and those could be drilled from the old ones so not even much of a problem either way.



I also doubt you are actually older than my grandfather unless you are in the mid to alte nineties, which i assume you are not or you wouldnt be texting here, as for the arogant youngster who is over his head, sure i can be arrogant, i am young, and i do not think i am over my head, if you never went to high school you wouldnt understand how much you learn there but i can guarantee you what they teach in high school nowadays is prob as advanced as the math you did in college (if you are as old as you say) also nowadyas we have the internet which makes learning absolutely anything a possibility for anyone, so what im trying to say is you dont know my capabilities, we havent met, so the only way you could have judged my capabilities is off of my age, but like i said, i dont think you understand how many tools and knowledeg young people like me can acquire using the internet, there relally is almost no boundary for capabilities in terms of knowledge anymore, not to say that i know everything, absolutely not, lol i have a life, i cant be siting down learning everything, but i learn what i can and need in order to dop what i want to do.

One last thing, all carb from the factory are probably so old (not as old as you though lol) that thery r probably all not running right anymore, so while that could be the prfect solution on paper, its not for me, and besides, like i said, i want to do my own experiments, nobody has done this to this scale, least of all you or anyone here apparently so who are you to tell me if its possible? i will find that out and let yu guys know so you can use it or learn from my mistakes

Have a good day and tahnk you all for your feedback

 

[SLM]

I wrote a similar post then deleted it, I think ebay may have a 4 carb setup, I wish young posters wouldn't abbreviate words 'thumb text' These posts are around for a long time and can help fellow enthusiasts. High revving engines require fuel injection or a carb for each cylinder. There's a guy 3d printing a motorbike manifold on youtube, He seems to have cracked it, but also admits vibration could just crack the plastic.

im hoping the rubber boot will smooth it out a bit, if not i could mount the carbs to the frame and have a flexible tube from the carb to the engine, although i dont know how i feel about a flexible "manifold" airflow over bumpy roads would be horribly turbulent

 

[ezcome-ezgo]

Turbulent airflow can be a good thing.

 

[SLM]

Turbulent airflow can be a good thing.

for torque and in the cilinder, not so much in the manifold no? i mean i guess it does help with atomization, i dont know i will see when I cross that bridge, for now ill just continue with the carb mounted to the engine

 

[Master Hack]

Hey if you can 3D print anything, and make it work, i say good on you, go for it. Tecnology marches on. Us old geezers are more comfortable with cast iron, 1/2 inch bolts, and steel, heavy unbreakable steel.
If you know how to print parts to build a carb, go for it. You may make a discovery along the way....
If it doesn't work well so what? Ya lost some time and a few bux. But learned something also.

 

[SLM]

i mean not ANYTHING anything, but pretty much everything that i would need on a daily basis and then some
Exactly! thats what im thinking, so what if it doesnt work? ill go back to what has been proven to work, but i still want to explore new grounds since there are advantages if it works, i understand that some people prefer older technologies, personally cars should have stopped evolving after 2010, but oh well, it is what it is, to each his own

 

[Denny]

personally cars should have stopped evolving after 2010, but oh well, it is what it is, to each his own

See you are young and still wet behind the ears. Cars should have stopped evolving after 1972.

 

[Master Hack]

Cars should have stopped evolving after 1972.

Absoutly! It all went to hell in 73!
big difference between elvolving and gov mandated evolving.

 

[SLM]

See you are young and still wet behind the ears. Cars should have stopped evolving after 1972.

well as much as i like the simplicity of carburators, EFI has opened so many doors and the ease of tuneability is just undisputable, hp per buck at least
although i really agree that the muscles cars just before the emission craze were the 69 stingray is just perfection in design terms, too bad the performance didnt live up, not to say it was bad, just not as good as its looks were

 

[Denny]

68-72 Corvettes all looked the same. If it all stopped in 69 we would not have the LS6 & LS7 of 70 & 71 from Chevrolet or the 71 Hemi Cuda from Plymouth.

 

[SLM]

ok so i forgot to write this yesterday but
I ran out of filament (a spool of wire which is used as material for 3d printing, for those who dont know) and so I wasnt able to finish it in time,
HOWEVER, i have filament coming on sunday AND I have a prototype manifold ready, I didnt have my phone on me so had to take a picture with the computer, so i apologize for the lack of quality, also this is a PROTOTYPE, so i am currently working on the second version, cause after doing some simulations i found this one doesnt flow as much or as well as i would like it to (I should mention this is an exact copy of the Murray´s carb dual carb kit, not to say that i know better, just saying that the people who designed it were limited by space, ease of installation and compatibility issues with the cables nd all, since im doing most of that custom i get to make one that flows better) , the version im working on right now will be longer but will flow much better, also I decided to go with a twin carb setup as I found a good set of pwk34b s, however I still want to test the 3d printed carb so that will go on the other go kart engine






below is the new manifold cross section in CAD, might not look that diffrent but this on is (also unfinished btw) much more freer flowing