Dual carb setup question

[stickandtin]

I will be setting up a 634 Hirth for dual carbs. Should I use a dual carb intake with a balance tube(ie GEM)or should I use individual adapters without the balance tube? What are pros and cons of each option? Thanks

[pararailer]

I would say that the balance tube intake is better on a twin HR carb set up. If you are using HD carbs the balance tube may not be as important.

[stickandtin]

Pararailer, I'm new at this. What is the difference between HD and HR carbs and why is the balance tube more helpful with one and not the other?

[pararailer]

The HR carb is smaller than the HD. Back in the day when they put twin hr carbs on it was not much better that a single HD carb onless it had a balance tube on it. Its because only one cylinder pulls in a charge at a time. If one cyl only pulls through one HR, its getting less than it would with a manifold manifold and a bigger HD carb. So then they would connect the two smaller carbs with a balance tube. If it has two HD's on it each cyl will pull in a larger charge.
Kind of hard to explain.
Im no expert on 634's but I think they would use twin HD's with no balance tube.
I think the GEM twin carb mainfold was supposed to be a performance upgrade on a 440 or smaller Engine like a Sachs where twin HD's would be overkill.
In my opinion a single HD would be better than a twin HR on a 440 or smaller engine.

[obj1]

Here is a cayuga dual carb setup. no balance tube needed.

[bubbanoz]

love the use of the blue connecting material! are the dual high rise air filters factory Cayuga?

[stickandtin]

Thanks pararailer, that helps a lot. Going to take me a while to learn all the lingo. OBJ, I don't believe I have ever seen a dual carb setup like that on anything.

[obj1]

Bubbanoz, scorp11 said this is the setup we need to keep up with you and pararailer.

[stickandtin]

I bet if you put a blower on the end of those piggybacked carbs you could really up the HP.