Spin them suckers around

[robin1731]

I'm certainly having fun with it. I had those 2" v-stacks laying around so I stuck them on (literally). It will need some sort of filter and probably a stone shield to keep the big chunks and the rain out. That will have some limiting effect on the amount of air they are getting. For now, I'm using as much junk as I have laying around as I can.

It only takes a couple of minutes to change the jets on the Webers. The stock carbs almost need a re-work just to get to them.
I suppose we (notice the "we" Rob) can drill out the jets and then solder them up and re-drill them to experiment? Lot of wrench time involved going that way. I'm sure we'll talk about that later.

I am concerned about my choice of the polyester resin (readily available at the Auto Parts store). It's real brittle. I'm going to do a test later with a tube made with epoxy resin and fiberglass. Vibration and really rigid plastic parts generally don't get along very well and I'm concerned about cracking of the joint between the tubes and the aluminum base plates. There is a lot of weight cantilevered off the front. There will be bracing, but I'm not confident about that. (The epoxy appears to take longer to set up. The glassing takes a lot of time and there are 4 layers on each tube.)

The carbs will remain on their correct sides but feed the opposite jug (#1 will feed jug #3 and #3 will feed jug #1). That will make the linkage all inboard. With any luck I can utilize the outboard synchronizer on #4 so I don't have to design and build one for the cross-bike sync. Having it just inboard of the carb will be a plus since it would be tough to get to if it ends up near the centerline of the bike.

The biggest changes will/can be made without removing the carbs. Trust me.

[gregforesi]

Performance is a side issue.
More important is that it looks cool. And ya'll have to admit that it looks pretty cool.
The rear tube for the left is done. I figure I'm 25% home. My confidence level that this mess is going to work remains at 10%.

Of prime importance is that on the way home from Stockbridge today I did a vicious shift to second gear and my left knee must have hit the #4 v-stack screen. It be gone. I wouldn't feel horrible about that except that I have no idea where I bought them. The chances of buying one and having the screens match up is nill. I have a feeling that I'lll need to buy 4.

[Oldewing]

I know your pain on number 4 weber, that's why I sold the set off the Hack. My leg hit all the time, and they where too noisy for the putt putt that the hack will be doing.

[gregforesi]

AAhhh, but the sound young man. The sound. That Weber growl reaches to the soul. It's the sound of wild horses stamping their feet and chafin' at the bit.
Then you twist the throttle with malice aforethought and the horses get unleashed.
The growl turns into a roar.
The skin pulls back on your face and then...

Oh, sorry. You're talking hack. My bad.

I can't believe I knocked that stupid thing off. It will take at least a half day of searching around to come up with a match.

[gregforesi]

Work progresses (at least on paper it does).
Actually, the left side is nearing completion and the right side is well underway.
I've been working on linkages. I considered using cables with splitters. A mechanical setup appears to be easier to adjust.
There are a lot of pieces in this so I may look at a cable arrangement as well.
I am considering tack-welding tabs on the stock butterfly brackets. The choke attachment points are at the correct angle so they won't have to be altered. It looks like I'll be able to retain the left-to-right synchronizer.
The lower rod with the wheel on it is throttle. The upper rod is choke.

Linkages and fuel line.jpg

[Greg]

So what do you think your gains are over the stock system? And how safe are the carbs in the event the bike tipped over.

You're a Genius.........

[robin1731]

That linkage looks very much like I was thinking when we were emailing about these. Similar to a bell crank for a mulit-carb system on a car. You may even be able to adapt one of those for this.

[CYBORG]

i like the linkage set up. turns out easier then i thought. go for it

[gregforesi]

Rob, I was considering using small u-joints directly on the ends of the carb butterfly shafts. They would have taken up the angle between the attachment points. It ended up being too far forward (interference with the fan shroud/fan baffle plate) so I went with linkages. The geometry of the link points is slightly different left-to-right to eat the angle.

Greg, I have no idea whether this will even work. If they turn out to be as efficient as the stock system there will be no power gain.
This idea has been floating around in my head for 5 years and it's finally turning into pieces parts. I'm pleased that I can use stock carbs to try the idea out. I balked at blowing $800 on a pair of Webers and then finding out that the whole idea was un-tunable (or complete garbage). I'm hoping to learn enough with this system so I can make a decision on whether to build a Weber setup. Even with the fabrication proceeding I have questions that won't be answered until the unit is on a bike (icing is first in line there).

The hobby shop is out of the lightweight fiberglass so unless I go on a road trip to Hobby Lobby the right side is at a standstill. I'll putz with the linkage blocks today. The 1x3x1/8 aluminum angle (that everything in the center will mount to) is on the engine.

[Greg]

Greg . I think you are well on your way to making this thing work.....

[Whiskerfish]

Nice drawing but anything wrong with just choking one side with a manual lever on the carbs? You are going to loose the high idle function anyway.

[gregforesi]

The Weber's don't have any choke at all. You just flood the snot out of it to get it running.
Everything is cheap when it's only on paper. The real expense comes when you start making scrap (both the regular kind and parts that don't work out like you thought they would).

Although I show the linkages in the cartoon, my throughts aren't really far enough along on them to know how the throttle attachment and bracket are going to work out. I do keep looking at the stock mechanism mounted to the plenum. If that gets scavenged then I get the idle adjustment, throttle stop, and (maybe) fast idle for free. I would like to have the idle adjustment outboard though.

How about dual choke cables - one on each side. I'm not ambidextrous but I could practice.

Here is a picture of the resin setting up in the joint between the tubes and the aluminum base plates. Doing this part is a lot like watching paint dry.

IMG_0136_resize.jpg

Look ma, no support jig!
I was able to route the spark plug wires through the maze. That was a plus because I was thinking I would need new spark plug ends.
I have been searching for fuel-proof duct tape without any success. I suppose I'll have to break down and buy 1 3/4" fuel filler hose.

IMG_0138_resize.jpg

[CYBORG]

moving right along. and that exhaust looks interesting as well

[Whiskerfish]

Not withstanding all the other challenges I suspect you to be correct with icing being the potential show stopper.

[gregforesi]

Yeah, I'm a little concerned about icing. The Randakk manifolds stay pretty cool for a long time.
Too bad you can't blow through the carbs. A turbo or two would probably take care of the icing issue quite nicely.