Bought a set Keihin carburetors on Ebay from an YZF750 superbike.
This setup was 4 in a row so had to modify a lot on it.

Here made the brace and connecting rod to the other side.
Plugged the open fuel lines and acceleration fuel pipes.

Raw milled aluminum for the manifolds.

Both acceleration pumps connected on each side for better response instead of a fuel line to both sides.

Aluminum soldered with Alutite. A special soldering system without the expensive TIG welding. Just an open flame 380 degrees celcius and a scratch pin.

The raw hand milling to make the flow nice and easy going for the air/fuel mixture. Had a lot to do because the inside size was 35 mm and had to go to 41 mm.

Made the inside smooth  and outside polished.

Other side of the manifold.

Fitting the parts into the bike for all sizes and little changes.

Nice to see these stacks :-)

The carburetors are fitted with a hose of 50 mm.
Made some rings onto the carburetors to get to the 50 mm size of the manifolds.
And then to connect them with a hose clamp

Sync pipes and NOS foggers fitted in the manifold.
Next to make is an airfilter adapter that fits on the stacks.

Fitted 4 K&N filters for better airflow and to keep the engine free from contamination.

Bought 4 adjustable slow air jets to make tuning easier.

Made a video of the first run. Click on the picture for an impression.
I like the rattling :P Open stacks produce more power but not reliable to standard road use.
K&N filters were installed for that.
This first run was a base setup off the bench. So everything had to be tuned a lot.
That took a lot of time to get it right.