Very basic multiple carb sync. tech

Uh, that procedure is Ok for your idle, but what about throttle plate syching at other RPMS??? You need to disconnect the throttle linkage from the gas pedal, and adjust the other linkage so the throttle butterflys open at the same time and the same distance and produce the same flow at a couple different spots through the rpm range.

Having the carbs set the same at idle, is certainly important, but doesn't make any difference of the idle stops, when/if the throttle plates are not open equally at say 2800, where your engine is when running down the road.

So you really need to do a couple more runs through the sych tool off idle too. The once you get them matched up that way, take another look at you idle balance.

 

I just ordered one---I'll let U know how it works

 

Why wouldn't they be opening at the same rate if they are sync'ed at idle,unless you have sloppy linkage?

 

Is the linkage perfectly centered on the rods and the carb ends exactly in the same position relative to the throttle levers? Do both butterflys open to the same position at WOT?

 

I would think so,if not something in the linkage is out of wack

 

You can't have it both ways. If it's a street car then sync it at idle. If it's a race car then you worry about WOT and nothing else. Pick one

It really doesn't need to be bullet proof. They are just plastic. As long as you use the same gauge on both carbs and get the same readings, accuracy is not important. Both carbs will be passing the same amount of air. I have no idea what those numbers mean and I don't care. If the gauge reads the same on both carbs, they are synced.

 

Perhaps your linkage is simpler than mine. I have an adjustable rod that goes to a lever on a cross rod.
The cross rods have an andjustable lever for each carb, and the lenth of the rods that connect the levers to the carbs are adjustable. So all those variables are tunable, and are seperate from the idle stop adjustment. So when mine are synched at idle, if the rods and levers ore out of adjustment, as soon as the carbs are off idle circuit, then can be no longer in synch. Mine are set up similar to a 4 cyl bike where the trottle cable actuates a rods which actuates the carbs, and all the inter connectioins are tuneable. You probably don't run into that with 2 2bbl but I would think that on 3 2's with progressive linkage you the forst and 3rd would also be tuneable and would need to be synched so thier throttles opened together and for the same amount.

Guess I used to dealing with straight 6's and 4's with multiple carbs and non progressive linkage.

 

All I can say is if U R running more than one carb---BUY IT!!!
This thing REALLY works,I just had Uncle MAX here on the HAMB rebuild my carbs,He does a REALLY good job and fast,I put the carbs on and adjusted the mixtures and idle and it was running smoother than ever---THEN I got the Synchronizer in the mail and boy was I off base--re-adjusted the air-flow&idle with the new toy and then a HUGE difference!!Now it is so smooth you wouldn't believe it!
Really a good investment Go to E_bay and type in carb synchronizer There are others on there but I got mine from Webercarbs direct $27.95 and free shipping

 

Great glad to hear it. Ain't it easy with the proper tool?

 

Do they have an adapter to fit early AFBs? I'll be running 2 with the 4 and 1/8" tops.

 

I don't think so,you would have to make one (adapter)

 

ROCKY,
you might be able to use something like this,I believe I've saw them made out of rubber at pluming stores (I think rubber would be better)

 

Can't get a pic to post . What I was referring to is a 4"X2" PVC pipe reducer.
you might have to take a little out of the ID to get to 4 1/8. I believe they make them out of PVC and also rubber (which would probably be better)
Check out your local plumbing store---GOOD LUCK!

 

here it is

 

Great tech article! Now I gotta idea on how to tune my 6 twos on my Nailhead. I'm running straight linkage, seems like it makes it some what easier than progressive. Thanks for all your help

 

I'd have to disagree with you on that. With progressive linkage all you have to sync is the center 2 carbs. The end 4 don't pass any air at idle so they don't need to be synced. They just need to be completely shut

I learned how to do this on a Man-a-fre 40 years ago. 4 carbs all working at the same time. It was a PITA but I kept at it and finally got it. Every time you adjust one carb the idle speed changes and you need to readjust the linkage and screws to get it to the desired idle speed. It's bad enough to match a pair. 4 were a bitch and 6 ...I don't think I'd even want to go there.

I'd recommend 2 sets of 3 deuce progressive linkage. get each side set up and then sync the center 2 carbs...a piece of cake compared to chasing all 6 carbs.

Remember that these were never meant to run on the street. They were race car intakes where all that mattered was WOT. JMHO

 

I'll make a brief report on the webercarb synchronizer that Gary T. posted. It works great. I have been running duals for over 20 years and thought they were set up pretty good. Wrong. It didn't take but a few minutes to get them synchronized. I did have a little problem after reattaching the linkage, but it is still a lot better than before. Thanks to all for the info.

Hugh