intakes, interesting topic to me friendly discussion welcome

I've been reading up on a lot on dual carb intakes and have found there seems to be 2 different camps.One follows the single plenum intake theory for dual carbs and the other are firm believers in the individual runner per carb for dual carbs.I've found from browsing the internet both styles of Intake available from manufactures.My KR intake/carb schematic shows dual runners.A head porter who has a pretty good blog about engines as well as Christian related posts is but one example.He displays a rectangular shaped dual carb intake IIRC on a flow bench that appears after close scrutiny to be single plenum.He also features information learned from classes given by Joe Mondello<sp>The gentleman I purchase my linkert parts as I need them shared during a visit today that he has examples of both single and dual plenum intakes,both obviously to him from casting techniques,etc. "factory" built and other pieces of his collection are crude enough in their build execution he believes they could only be the resulting effort of unknown individuals.
I'm posting this in hopes of educating myself on the merits as well as the pitfalls of each manifolds fabricators chosen technique.Mods please close this post if it becomes no more then a conflict between supporters of one or the other styles.I've been here nearly a decade and this is my "go to" board when seeking to further my knowledge,due to the knowledge base of members as well as the frequent visitors. I'd like to share with those that may be unaware a Dutch website I find very informative as well as entertaining http://motorvitamine.eu/www.motorvitamine/index.php I due only to personal preference use google translate to enable me to read the posts.

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Panic for linkerts I have 2 complete M51's currently bone stock with factory parts as far as I can tell.For conversation sake please share your knowledge on the merits and pitfalls of each style of intake with the forum if you would using the common 3 bolt Harley linkerts as the example.Engine size in my case for example only is 58" I believe the engine builder said.

I've been reading up on a lot on dual carb intakes and have found there seems to be 2 different camps.One follows the single plenum intake theory for dual carbs and the other are firm believers in the individual runner per carb for dual carbs.I've found from browsing the internet both styles of Intake available from manufactures.My KR intake/carb schematic shows dual runners.A head porter who has a pretty good blog about engines as well as Christian related posts is but one example.He displays a rectangular shaped dual carb intake IIRC on a flow bench that appears after close scrutiny to be single plenum.He also features information learned from classes given by Joe Mondello<sp>The gentleman I purchase my linkert parts as I need them shared during a visit today that he has examples of both single and dual plenum intakes,both obviously to him from casting techniques,etc. "factory" built and other pieces of his collection are crude enough in their build execution he believes they could only be the resulting effort of unknown individuals.
I'm posting this in hopes of educating myself on the merits as well as the pitfalls of each manifolds fabricators chosen technique.Mods please close this post if it becomes no more then a conflict between supporters of one or the other styles.I've been here nearly a decade and this is my "go to" board when seeking to further my knowledge,due to the knowledge base of members as well as the frequent visitors. I'd like to share with those that may be unaware a Dutch website I find very informative as well as entertaining http://motorvitamine.eu/www.motorvitamine/index.php I due only to personal preference use google translate to enable me to read the posts.

I once knew a fellow who was the Head Porter for the Texas and Pacific Railroad, but he did not know too much about motorcycle carb plenums, as I recall.

IMHO, though, a single manifold system would seem to allow two carbs to balance their flows between cylinders in a somewhat similar manner that dual exhausts on a car are improved by a crossover pipe that helps scavenge exhaust flow.

Maybe I have simplified this too much, but based on the one removed post, there does not seem to be a need for a concern on the part of the moderators to close this subject based on the conflicts generated. So if I have made too general an assumption, please chime in and steer me in the right direction.

most of the twin port conversions I have seen are the separate port variety. I would think that you would get better gas flow velocity that way, certainly on a 45" engine. I'd also rather think that you would need to do a LOT of tuning to get any real benefit from them; I saw a thread a while ago about a 45 with a pair of cv carbs from a Suzuki GS500, which seemed to go well, but then again no information was offered about how far they were open.

I would tend to believe that the best avenue would be to look at more advanced carburation, rather than more carburation. You will get better starting, better acceleration and far better fuel consumption from an Amal Concentric and an afternoon with a few main jets than you will ever achieve from a Linkert, whatever you do to it; use a Mikuni and you won't suffer from the freezing-up on cold, wet mornings that you sometimes encounter with Amals.

You will get better starting, better acceleration and far better fuel consumption from an Amal Concentric and an afternoon with a few main jets than you will ever achieve from a Linkert...

You know this is akin to blasphemy on this site?

But I do tend to agree (with NO scientific or quantitative findings) that what a 45" really needs is BETTER carburation, not more carburation. Unless you're doing LSR or drag racing, I'd think a 1 1/4" carb should be enough for any streetable 45".

Not exactly HD, but I had a '69 chevy truck with a 396 and a cam designed for towing in it. The think was a dog.......and sucked the gas. It had a 750cfm carb on it. Traded for a 500cfm with smaller primarys and guess what...........the thing ran better from idle to whatever, had a ton more torque, and used way less gas. Point being..........big carbs are great if you are running WFO.......but 99% of us are not. Harleys are not crotch rockets (or even big block chevys) but, from idle to 3500-4000 RPM is where I'd think most of us are shooting for.

OP........if you're building a LSR or drag racer........forget everything I said, and continue on.

not that I want to disagree with you hdrl1935 but I have popular current literature stating the linkert lacks the technical refinement of newer carburetor designs.And I quote "An additional limitation is size:the largest common factory venturi is only 1 5/16" in diameter(slightly over 33 mm)and even the rare after-market venturi is only 1 3/8" (just under 35mm).end of quote.The literature I'm referencing additionally states that the linkert is not well streamlined internally,due to the throttle shaft and disc,mechanical choke and will not flow as much air as a comparably sized modern carburetor.And lastly I'll end referencing said literature with this final quote What this means in plain language is that in some cases(especially in large-displacement engines)there will be less power available with even the largest linkert then with other larger carbs.

This information I've share with you is provided by one of the foremost linkert experts and regarded by most if not all that frequent this board as well as a few additional forums as such.So in quoting and given credit to the literature owner though un-named you should realize that someone with 3 or 4 decades of experience with the linkert carb has clearly stated that even the biggest linkert is to small in some cases then adds after that statement that it's especially true in large-displacement engines.Given the grasp of the English language as the bulk of our U.S. members have one can only infer by the previously mentioned statement that engines other then the large displacement engines still indicate the largest linkert is too small.

Again I'm not interested in a pissing match just sharing an experts opinion regarding your belief that an 1 1/4" is enough for a streetable 45" engine.The term streetable in its self is open to opinion,to one 45 owner it might mean running a box stock 45 engine,to another 45 owner his definition might be a full tilt bored and stroked engine with maximum cylinder work,huge cams that one can verily get to idle,a huge carb with all the current tricks that leaves you the choice of idle or full throttle with nothing in between,etc.,etc.

Again I don't mean to offend I'm just sharing well documented facts from various sources written by some of the most highly regarded individuals that direct their skills and energy to research the flatheads we all love and provide us less skilled,or perhaps highly skilled but lazy individuals with hard facts that they can back up with additional hard facts if need be regarding the flathead,linkert carbs,etc. their shortcomings and what does and doesn't work effectively with them.

[Pa]

Linkert for vintage purposes. Fuel injection, calibrated respectively, for highest performance on any other usage of a vintage primtively designed engine. Pa

Greg posted: "I have popular current literature stating the linkert lacks the technical refinement of newer carburetor designs"

Please do not take this personal, Greg, but what the hell do you expect modern experts to profess?

How else are they going to sell you something you don't need, when a run-able Linkert can be put together by a child?

If refinement is the criteria, vintage anything is out of the question! Time to go buy a modern ride and forget all that romance and adventure.

....Cotten

Al Crocker proved a smaller carb was more suited for a street racer as did Carrol Shelby on the race circuit. Hi-Po 289 only ran a 525 CFM carb. Crockers ran circles around the competition. Bigger is nice if wide azz open but through out the range a smaller carb is better used. Just my opinion, no scientific studies only facts on the road:) As far as a Linkert not being anything like a modern carb, with all due respect to our hosts S&S cycle their Super B appears to be a linkert on steroids and they'll run pretty strong.

Cotten I'd like to respond to you personally as you may or may not remember I'm a huge fan of the linkerts.I posted pictures of a couple M53's I rebuilt not long ago and was thrilled you responded to my post in a very positive manner as the post contained pictures of both the M53's I went through.I currently have the M53 with the near n.o.s. body and original bomb site venturi as well as a couple M51's.I'm hooked on linkerts and will mostly likely always have at least a few of them around.I have numerous parts for them,have bought,traded,and sold a couple dozen of them this past summer to build up my linkert fund enabling me to buy the pair of M53's as well as a M53A1 and the I've been told super rare M25S.I wouldn't ride a new bike across the steret my late model was a 1982 fxwg bought new 70 miles from where I'm setting that I rode for decades.The point of my post was meant to be informative and helpful.I just felt the need to share with the previous poster that the 1 1/4" carb isn't for the most part regarded as the most linkert a 45 might need.As you know and/or can easily find I've been a member of this board for nearly a decade and have never been one to post negative or spitefully.My dream carb at the moment is an aluminum MR3 just because I personally equate the linkert to art.I know the MR3 is a racing carb and of no use on a street bike,I'd buy one if priced right just to set on the mantle.Bottom line I think any linkert is the best thing since bottled pop.And I've had a dozen or so various other brands including S.U.s,S&S super B,S&S super E,and numerous others I can't recall the brands at the moment,I have c.r.s. can't remember shit syndrome.If I was in any way interested in newer bikes I would have spent the last decade and several vintage motorcycle board reading and soaking in all the information possible.Anyway again I'm not and have never been a shit stirrer on this or any other board I'm a member of,it's just not in my nature...........

The info about the twin Suzuki GS-500 Carbs was from Vince, aka Enigma here. Search his posts.

He was kind enough to send me photos of the homemade manifold and mouning on this 45.

I have partially made the manifold, and I have two sets of these carbs to play with. Along with the 34mm Mikuni.

George

Greg!

You went and took it personal.

This is still a friendly discussion!
It is just too much of a paradox for me to exalt vintage motorcycles, but then decree that they were junk and new is so much better.

Or that BIGGER is always much better.
Does anyone stop to consider WHY the MOCO used little 1" models on the Servis?

....Cotten

George,45Brit, I copied Vince's ideas and built up a dual runner setup for Frankenstein.
http://www.freewebs.com/dick_linn/ . All verbage is courtesy of my Son, who built the site for me.
At any rate, the twin 33mm CV's were Very Smooth responding, pulled nicely from idle, and did NOT give the top end of the single 38mm VM previously mounted. After a season spent tuning, I went back to the VM. I liked most everything about the Dual Runner, each cylinder obviously liked having its own carb, but the carbs were too small for a 1000cc KHK motor. George, if you want to save some work and want to see for yourself send a PM.
DD

You need to think of what cylinder size the carb suck through. So dual carbs on a single plenum is twice as much carburation as the same dual carbs on dual separat runners.

Patrick ( frenchowl ) has a thread on here as well, about twin carbs on his K model.

One thing I do know about CV carbs, is that they give very good response on low inlet vacuums, which means that they provide smooth carburation for sidevalves - because they are never fully open anyway. You can be bold with the sizes for the same reason, if they are too big they just never open.

Herr Dr.

PM sent, and I visited the link you posted.

Nice work..

now if I could actually be able to make some real progress on my project, I would be a happy camper.


George

Cotten you got me on this one I guess I did post in a bit of a defensive manner.I just don't want to get the rap that I'm a twin cam fan or into metric bikes and such :>) .The linkert has become quite an obsession for me.I wish I had deep pockets as I have several on my "have to have" list.
Thanks to everyone for the additional information you've shared on this post as well.