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Discussion Starter · #1 ·
The photos are here & the story and pics are under Aircooled Pocketbikes.
 

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We have been using those manifold in the goped world every since ive been building them .
The HDA223 is a 15mm carb not 19 The inlet on one side may be 19 but the back is 15mm . Even Walbro list it as a 15mm carb.
We use the Hda48 on polini or the HDA 77b. They have a slightly bigger inlet and perform allot better. With this carb linkage.
davesmotors.com/s.nl/it.A/id.1307/.f
I have a SDC80 carb I will be using it is almost 20mm for my polini build. If any one needs a Walbro manifold they are quite easy to machine on the mill I could make one.
walbro.com/parts-service.aspx

You are going to love the HDA carb its so much easier to tune I think the the dellorto carb.
 

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Discussion Starter · #4 ·
I have a 223B, it's 19 in the front 16 in the middle and 19mm in the rear, you must have an older model. I had to hog out the 16mm manifold to 19mm and put a Dave's 20mm tall V-stack. Plus it's a purge carb.
 

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Discussion Starter · #5 ·
Here is the rubber / steel C1 manifold almost ready to mount the Walbro Cag alum manifold to it, 2 holes and countersinks & SS Screws and alittle seal on top the screws, and it will be ready. Should have the SKF French bearings and seal from Germany in a couple of weeks, with it the the Billet Cag engine cases, and its bearings and seals, and Polini reeds.
 

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Discussion Starter · #6 ·
Re: Update 1 Photos of 19mm Walbro HDA223 to C1 Intake Manifold

Here is the 19mm mounted on Cag alum manifold bolted to the rubber/steel modded stock C1 manifold. Only thing left is the purge port & boost port fitting on top the Cag manifold part. The purge fittng has to intersect the pulse hole to pump gas.
 

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I have a 223B, it's 19 in the front 16 in the middle and 19mm in the rear, you must have an older model. I had to hog out the 16mm manifold to 19mm and put a Dave's 20mm tall V-stack. Plus it's a purge carb.
When it comes to the size of the venturi, it's no different than any other HDA-223. There is no difference in the A/B/C/D and so on.

What you are playing with is, and will always be a 15.08mm venturi size carb. The venturi is in the middle.

Take a close look at your carb on the inlet side. Open the choke butterfly and look for the number stamped on the inside of the carb. This number is the venturi size, measured in 64ths. Yours will say "38".. meaning 38/64 of an inch is your venturi size. 38/64" translated to millimeters is.. dun dun dun.. 15.08mm!

Here's a pic of the inside of my HDA-48D (Also has a 15.08mm venturi):


Here's Walbro's website showing specs for the HDA-223:
http://wem.walbro.com/walbro/product2.asp?partnum=HDA-223-1&Series=HDA

Here's a spreadsheet I made a while ago showing the venturi size of EVERY DIAPHRAGM CARB that Walbro makes:
https://docs.google.com/file/d/0BzrY-Dy8RXfjallVX2l3Y2JzZEE/edit?usp=sharing

Don't believe me? Call Walbro for confirmation.
 

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Discussion Starter · #8 ·
There is nothing to believe, I already said in the thread 16mm in the middle, I am not going to nit pick over a .12mm smaller.
Been to Walbro many times. The 603 was made for 30 to 50cc engines the HDA223 was made for 50 t0 100cc engines. I have the 50cc model of C1, ( 46cc ), it has a copy 19mm Dell PHBG w/ 1.01mm main jet. It's alot of carb, hard to tune it, and I hate changing jets, messing around with atomisers, its a waste of time.
The Walbro runs up side down, no jets, floats, float bowls, needles, gas turn off valve and it don't leak all over the ground. I have a little screw driver in my pocket, 1/4 turn I'm jetted and ready to Rock and Roll.
 
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