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Wed Aug 28, 2024 11:16 am

Hello everyone,

I bought these dual carbs from someone on marketplace, they have strange looking intakes and wondering is anyone has seen them before. He said he couldnt get them to sync up properly and upgraded to some webbers. This will be my first time messing with dual carbs and will need to order a linkage kit so I wont be installing and messing with them yet. The fuel inlet looks a little large for the stock tubing so I probably will downsize it, any reason I shouldn't? He said he rebuilt them prior to me buying them but I have a spring attached on one of them to a bolt and the other doesn't. I'm going to have to do some more research but if anyone can point out anything odd that I should look at?

Wed Aug 28, 2024 11:41 am

Those look like Kadrons. I don't use the stock Kadron linkage, I use one that is similar in style to the CSP linkage. I got mine from Kaddyshack, but I can not recommend them from my personal experience.

That spring from the linkage to the screw on top is to help the throttle return closed, they're on both of mine, on my bus engine.

Wed Aug 28, 2024 12:15 pm

otis_bartleh wrote: Those look like Kadrons. I don't use the stock Kadron linkage, I use one that is similar in style to the CSP linkage. I got mine from Kaddyshack, but I can not recommend them from my personal experience.

That spring from the linkage to the screw on top is to help the throttle return closed, they're on both of mine, on my bus engine.

Thanks, I'll try and get another or just a new set of springs, could be why he couldn't get them to sync correctly. I'll keep that in mind when I start looking for linkage.

Wed Aug 28, 2024 3:54 pm

I agree that those are Kadrons, also known as Brosol 40's (Brazilian Solex). In your 2nd photo you can see the letters "SOL" on the carb body just behind the nut for the manifold attachment.

The manifolds are one version of Kadrons, being steel. The other type are aluminum. The curved pipe on each manifold is for the vacuum equalizer "balance" tube. Use a sturdy hose for those such as the reinforced stock-style 1/2" ID air filter breather hose.

You can de-rust those manifolds by sandblasting, or soaking them in white vinegar overnight. Or also Evapo-Rust.

Kads originally had small metal ball studs at both throttle levers. They snapped into a ball socket at each end of the original Kad crossbar linkage. The linkage worked reasonably well as long as those ball sockets did not develop any slop from wear and lack of lubrication. Your throttle arms do not have those ball studs, which were press-fit and peened into the arms. However, there are slightly better solutions for linkages, such as the Scat center mount swivel, the Gene Berg style with "down rods" ($$), and the "CSP"-style center mount swivel.

The idle jet is seen in the first photo. It's brass and has a hex-shaped head. Use an 8mm wrench to remove it. You should be able to read the jet size after you remove it, stamped in tiny numbers. Typical size is 55.

If you have original style air filter assemblies, they have a single mounting stud. That stud is mounted off-center on the air filter, so that once you have the carbs on the engine you can rotate the entire air filter to clear the fan shroud and have the most clearance between the engine compartment side panels and the front firewall.

Wed Aug 28, 2024 5:08 pm

Go to Kaddieshack.com and read his tech articles and videos, lots of info there.

Thu Aug 29, 2024 10:48 am

here is a photo of my kadrons and linkage...have blow it up.

Thu Aug 29, 2024 8:34 pm

I too am running a set of those Kadrons. Fairly simple carbs to use and tune. There is a book out there with tons of good info and I highly recommend you grab a copy. I'm using the SCAT linkage and like it.

Fri Aug 30, 2024 9:32 am

one of the design issue with Kadrons is the discharge hole where the idle mixture exits the carb is on the side with the mixture screw...so as a result more of the fuel mixture goes down the manifold port into the cylinder closest to that screw....so they tend to idle on those 2 cylinders which could be what the PO means when he claimed he couldnt syncronize them...they are very sensitive to fuel pressure(needs to be low) and they'll also drip out of the pump nozzles if not set up correctly...been a while but found a lot of good info on AJ Sims LowBugget site...with the built-in air cleaner stud you'll need a piece of tubing to stand on top of the carb io use a Uni-Syn

Fri Aug 30, 2024 11:09 am

volksworld wrote: ...with the built-in air cleaner stud you'll need a piece of tubing to stand on top of the carb io use a Uni-Syn

A Pringles can cut to size is perfect for this. (Just clean it good first :lol: )

Wed Sep 04, 2024 1:23 pm

Thanks for the all responses, I stopped getting email updates and didn't know anyone else replied. I will look into the sites and try to figure out how to set everything up properly.

Wed Sep 04, 2024 1:49 pm

OrangeMango wrote: Thanks for the all responses, I stopped getting email updates and didn't know anyone else replied. I will look into the sites and try to figure out how to set everything up properly.

Be mindful that unmodified Kadron's will not provide enough ported vacuum to work an SVDA or DVDA vacuum canister on those distributors. Kaddie Shack does the modification.

If you don't have them modified, you'll need to use a mechanical advance only distributor like a Bosch 009 or 010.

Wed Sep 04, 2024 4:46 pm

Dual Kadrons with a 019 would be a good way to go.

Wed Sep 04, 2024 6:26 pm

If you're going to run a mechanical advance only distributor with those dual Kadrons, run a Bosch 009 or Bosch 010. The 010 would be first choice though they are expensive.

I ran a high compression 1835 with dual Kadron's, a German Bosch 009, dual mufflers in a cal look VW bug back in the mid-1980's. I ran low 14 second quarter mile runs with it.

I would never run a 019 in a bug. It has a short ramp rate and only advances to maybe 15-16 degrees. The 019 is basically a BR8 late 50's bus distributor. Those split buses also used reduction boxes and had a max speed of what? 50-55 mph?

Mon Dec 09, 2024 8:57 am

So I made a trip down to socal and picked up the linkage, heat riser block offs. I had some time this weekend to look at everything and noticed a few things I though I should ask about.
1st the bolts on these on the inside look to be cut, assuming to fit through the hole, is this normal? I feel like it would be easier to run a bolt going down and a nut at the bottom
2nd the idle jet on one of them looks rusted up, I will pull this off and take a look but might just need to replace it.
3rd the fuel inlets are 2 different sizes, this is not normal right? One is reading at about 4mm inside diameter and the other about 5.6mm inside diameter.

Between the idle jet and the different size fuel inlets I can see why he might have been having a hard time syncing them up.

Lastly is it possible to run these with a vacuum advance distributor and capping off the vacuum port? I will buy a different distributor, I just want to see if I can get them installed and idling without replacing it right now.

Mon Dec 09, 2024 9:50 am

Kadrons have to be modified to add the vacuum port to them. If you can add the vacuum port you can get a 034 distributor.

Mon Dec 09, 2024 11:21 am

OrangeMango wrote: So I made a trip down to socal and picked up the linkage, heat riser block offs. I had some time this weekend to look at everything and noticed a few things I though I should ask about.
1st the bolts on these on the inside look to be cut, assuming to fit through the hole, is this normal? I feel like it would be easier to run a bolt going down and a nut at the bottom
Correct; one bolt head is sliced to accomodate the "intrusive" angle of the inner face of the intake manifold. Insert the bolt just like you have it, with threads going UP. You first assemble the carb to its manifold OFF the car, then place the unit onto the cylinder head. Make sure you use lock washers under the nuts for the carb.

2nd the idle jet on one of them looks rusted up, I will pull this off and take a look but might just need to replace it.
Ugh- somebody ground off the outer face of the idle jets, which normally have the idle size stamped in (tiny). Baseline jet size is 55. Use an 8 mm box-end wrench to loosen the jet.

3rd the fuel inlets are 2 different sizes, this is not normal right? One is reading at about 4mm inside diameter and the other about 5.6mm inside diameter.
I have a pair of Kads in the basement which I'm reviving. Both have the 3-barb fuel inlet fitting with 4.0 mm ID. OD at largest point of barbs is ~ 7 mm. The metal fuel line which came with the set, and is used to mostly distribute the fuel between them, has 6.5 mm OD.

Which linkage did you buy?

Mon Dec 09, 2024 7:16 pm

I ran a high compression 1835 in the early 1980's with dual Kadrons, dual mufflers and a Bosch 009 mechanical advance only distributor. That engine did low 14's in the quarter mile. The 009 worked great with that set up.

You don't have to run an SVDA with those carbs. A 009 or even better, a 010 works very nicely with those carbs.

Tue Dec 10, 2024 5:59 pm

One of the reasons people have trouble synchronizing Kadrons is because the linkage that comes in the kit is horrible; at least the set of Kadron linkage that came in my kit 25 years ago did. At the time I couldn't understand why. My understanding is that that linkage set never improved.

The ball ends will start popping off at random in a short timeframe (at least mine did). Then there is the issue of both carb arms attaching on the same side of the pivot, meaning the linkage between the carbs is a fixed length, while your engine is not - due to thermal expansion and contraction. This doesn't seem like it would matter that much but it has more of an effect on synchronization than a lot of people would believe, and is even worse if you're not running a thermostat to keep the engine width pretty stable.

Your linkage arms at the carbs look very much like those that come with the Scat universal linkage kit; maybe that's what the PO tried out. By the nature of its design, it too suffers from the fixed-length issue. I spent a lot of time and effort trying to work around this on my Scat universal kit, with no success.

If you're going to run a center-mount linkage, consider one that mounts the carb arms one on either side of the pivot, that way when the engine width changes, the center pivot just twists a little and self-compensates for the width variation. This will go a long way toward holding synchronization. Just make sure it's designed in such a way that the geometry between the center pivot and the carbs holds very close to the same angularity on both sides. Otherwise they'll synch up somewhere in the range of motion but not hold that synchronization throughout the throttle travel. Intake manifold height and center pivot height will both come into play here, and it may be difficult to get it right.

I may catch a little hate for this one, but although pricy and not exactly perfect, the Berg linkage will get you really close to having carbs that will synchronize and stay that way. They're fairly easy to get the linkage rods geometrically similar, and don't suffer nearly as much from engine width variation. Just read and understand the installation instructions - they are a little difficult to follow when they describe bending your brand new linkage to finalize synchronization, but if you think through it before actually bending anything it will make sense.

When I ran duals, the Berg was my third and last linkage kit. It was the best solution for my no-thermostat engine.

Hope this is helpful.