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Discussion Starter · #1 ·
Been working on my project for a while now. First time post on here, but from google searches it seems there is more experience and knowledge in this forum regarding single carb conversions.

Here's what I've got: 1976 GL1000, EMPI 30 PICT-1 single carb, and I've built the manifold myself. Just got it running last night, but it won't idle on its own after warming up. I suspect there could be an air leak but I haven't found it yet. I only just started testing it last night.

I haven't changed the jets yet, but before I start ordering a bunch of different sizes, I thought I would ask if anyone has used a similar setup. If anyone here has done one similar, what size did you use for idle and main jets?

Here's a pic of my setup:


And if you're curious about the build of the bike in its entirety, heres the build thread: http://www.goldwingowners.com/forums/showthread.php?t=22329
 

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Hello and Welcome Frankenwing .
We do have some members here who run single carbs . I hope they will be along to offer there thoughts .
I am thinking you may have problems with such a long runner from the carb to the plenum . I think I understand your carb placement with the suspension system .Well after reading your build thread I see I was wrong in thinking there was a problem fitting carbs around the suspension mounting .

I do find the suspension quite interesting and can see you put some thought and work into this .
Another option that has been used is twin throat carb on each bank . Sorry I dont know the model/brand . Seems it is used in performace VW engines .

Here is another site link with folks who run single carbs :NGW Club--Goldwing Forums

Please enjoy the forum here and let us know how you solve this problem . Now back to read your thread on the bike build . Thanks for sharing . Well thats an interesting build for sure . Enjoyed reading about it .
 

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It aint rocket science
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Not a fab guy here more nuts and bolts OEM type but can't help wonder why a remote mounted carb?

My thought is that by the time the air/fuel mixture goes through 2-3 ft of twists and turns the fuel would just be dribbling into the intake valve opening.
 

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Discussion Starter · #5 ·
Another option that has been used is twin throat carb on each bank
I'd actually love to do that eventually. But those double barrel webers are really expensive. So thats for another day.

But! i've got it all working. Idles a bit weak at the moment, but ordered new jets on monday and waiting on them to arrive to fine tune it. Other than that though, its super smooth. No lag or bogging down. And full powerband straight to redline! And I love the new sound :)

Some pics:



 

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Not a real techie type here, but with the carb not getting any heat from the engine, do you think it might be "cold carb" type issues?
 

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Nah. Electric choke works fine, I know for certain. When it's warm it's still an issue.
You made too long central intake tube + manifold + "cold" carburetor. That's why you still have idle issue. You need to make a flange and weld it to the center of the X-type intake collector.
 

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You made too long central intake tube + manifold + "cold" carburetor. That's why you still have idle issue. You need to make a flange and weld it to the center of the X-type intake collector.
I'm guessing that there isn't enough room at center of engine to clear the harley-type fuel tank, hence the rather extreme offset. It will be difficult if not impossible to get it running properly like it is. Need to figure out how to shorten the runners to distribute fuel mixture evenly. Only other way I can see would be to go with a dual carburetor setup. The electric choke only controls the startup fast idle setting. The setup that Sergey and I have uses the original heat tubes to heat the manifold runners. Even while running I was surprised to find how cold the carburetor feels on the outside.
 

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I saw the pix of your setup on another forum Frankenwing. On one picture your bike is shown stripped with a new melted frame without tank and carb (s). I can bet there is enough space to mount a single carb vertically. I would suggest to make a lower manifold with a flange on the center, mount a carb and connect an air filter also vertically just between your two-pieces tank using a vertically tube. So the filter will be on the top just in the center of your tank. For fresh air going to the carb it doesn't matter but you will have shorter intake runners and will not have any issues with idle.
 

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Discussion Starter · #12 ·
Everything dialed in. If anybody is interested, 41 mpg.
Thats fantastic.

I saw the pix of your setup on another forum Frankenwing. On one picture your bike is shown stripped with a new melted frame without tank and carb (s). I can bet there is enough space to mount a single carb vertically. I would suggest to make a lower manifold with a flange on the center, mount a carb and connect an air filter also vertically just between your two-pieces tank using a vertically tube. So the filter will be on the top just in the center of your tank. For fresh air going to the carb it doesn't matter but you will have shorter intake runners and will not have any issues with idle.
I've been thinking the same thing, at least by making a new manifold that doesnt connect to intake tubes. Instead i think what id like to do is make one that goes directly to the intakes on the heads, cutting out the stock intake tubes altogether, I could gain maybe 2 inches that way. Down the road i intend to make a better manifold anyways, since i had galvanized steel for this and the welds do not look pretty.

But according to the math, the distance the carb is from the heads isn't an issue. It all adds up fine. Ive already seen a similar setup work just fine, but it also took a lot of tweaking to get it right.

I got my jets in this week, and it made a slight improvement. But i still suspect a vacuum leak. Ive read a lot of complaints regarding these empi carbs not being good as is out of the factory. I can make it idle relatively normal by adjusting the fast idle screw, but where its set i know it isnt right.
 

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looks like the best way for frankenwing to go is maybe a second 30 pict-1 carb, and go to a two carbs set up with short manifolds at the heads.
 
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