Copperwing wants a single carb so... copper manifold

Since I went with a copper theme in customizing my bike, I have wanted to make copper downtubes for the stock carbs. I just hadn't been able to figure a good way to connect copper plumbing to the heads. Frustrations with the stock carbs had me considering a single carb and then I found inspiration here: https://classicgoldwings.com/forum/viewtopic.php?p=137161#p137161 Special thanks to Canukxxxx!

So here starts my single carb journey...

I hit up the local metal recycling yard and found these materials just begging to be brought back to life. I bet they didn't quite have this in mind...
1' x 2' piece of brass sheet, (for other projects)
4" piping with a cap for the plenum,
various pieces of 1" pipe with 90* elbows for the runners and downtubes
roughly 5' piece of 1" pipe,
and the best piece, a 4" x ~16" piece of 1/4" copper plate with holes that fit the pipes. To be used as flanges and, if I have enough, to mount the carb.

Canukxxxx said the doughnuts would be easy to make from the plate, if I had some hole saws and a drill press. Well, I had neither. I convinced the wife to let me get the hole saws but the press was a bit too much. I screwed a piece of aluminum plate to my trailer bed, bolted and clamped the copper to it, and started drill/sawing.

I cut a grove for the o-rings, then cut out the doughnut. I smoothed the o-ring grooves with a dremmel, and sanded away until pretty and shiny.

Half way there on the flanges, but the kids wanted to go swimming...

What do you intend to bolt them down with? Some kind of stepped washers?

Oh, I have some aluminum plate that I'm going to put over the top of them like Canukxxxx did.

I think I might make a pair of "Y" shaped ones per intake to show off the copper more

Y shaped is like distributer hold downs. That'd be cool.

What's your plan sealing to head? O ring or gasket?

Zoomed in a bit.

I am planning on using an o-ring in the groove here. I used a 1-3\4" hole saw to cut down about .070" and then smoothed the channel with a dremmel. The o-rings I have are about .140" thick and fit nicely in the groove.

I will solder these to the pipes and make y shaped pieces to hold them down to the head.

Nice!

opcorn:

Just wanted to give you a heads up, Bug, to check the spark plug boot assembly clearance with these flanges in place. I had to do some grinding on my steel flanges so the plug boots would fit down tight.

Thanks for the heads up! I'm running a full dyna ignition/coils/wires and the iridium resistance plugs so I'm not using the boots or well covers. (I make sure to blow them out every once in a while so they'll drain). I did check them just to be sure though.

Cool.

nice ....looks great.... opcorn:

Ok, slow progress. I finished cutting out the other two flanges and polished them up a bit more.

I'm not sure why I kept thinking about using the aluminum plate to make the hold-downs, I'm going to have plenty of scrap from around these cut-outs. I'll see if I can make the larger area to the left fit whatever carb I get. Do you think 1/4" of copper is thick enough to tap and bolt the carb to?

1/4" inch plate should give you plenty of stiffness and hold threads. If you want to make certain though you can silver solder some brass nuts under the plate for more threads to hold it.

hmmmm it would be a gamble ....the carb throttle and motor are always working on it in twisting way

Once everything is soldered together, I think 1/4" will be fine, for threads too. I would use threaded studs then nuts to hold down the carb.

Jeez, I have been asleep at the switch here...didn't even see this thread until now. :lazy: Looks like you are making good progress. I never even considered making the O-ring grooves with a hole saw but if it works, why not.

Are you going to make Y shaped hold-downs, like an old Chevy distributor, to hold the flanges down to the head? :shock:

I will be following with interest. opcorn: opcorn:
Brian

I am a little worried about the grooves. I don't have a drill press to keep it level so they're a little uneven. I will probably have to get a finer bit for the dremmel to smooth them out.

That's what I was thinking to hold them to the head, but the more I think about it. I start worrying about them angling up when I tighten them down. If I have enough scrap material, I might try U shaped pieces. I know I don't have enough to make full rings like you have.

I purchased a holley 740 (list 9685) from fleebay yesterday,. It should arrive around Wednesday. I'm waiting for it before I go much further, so I can make sure it will fit behind my alternator.

I'm glad that you are taking a step back. Workmanship and attention to detail are everything with custom bike.
Those copper (or brass) doughnut are the first step and have to be made just right; outside diameter the same as the width of the head flange, inside diameter a nice fit to the copper pipe for a good, neat solder joint, and the o-ring groove exactly the same as the OE elbows.
As far as those floating flanges go; I made all four out of about a foot of 2" x 1/4" aluminum flat bar. The nice thing with that flat bar is that, once you have all the holes drilled it only takes one diagonal cut for each flange. Then some filing to shape.

Good luck
Brian

Here are the flanges laid out on the aluminum flat bar.