dual Weber manifold question

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dontwantapickle
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dual Weber manifold question

#1

Post by dontwantapickle »

I finally pulled my empi 40idf carburetors out of storage for this ongoing project bike I have here.
Now, I'm gonna figure out how I'm going to mount them.


I know that randakk makes/made manifolds, but I want to see what other options may be available.

There is the guy on youtube that made his on a 3d printer, and that idea really interests me although I am a bit concerned about the durability of the soft printable plastic.

Whatever I end up making, I want to do some design testing to hopefully optimize performance.

Have any of you guys made your own manifolds? Any Pics ????

I am open and looking for Tips, Tricks, Hints, Opinions, Etc......
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ericheath
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Re: dual Weber manifold question

#2

Post by ericheath »

For dual Weber’s probably not as big a concern, but the “fad” of using PVC pipes for manifolds have been around for 4-5 years with single carbs. One poster came back to inform us that his blew up. I can’t see how you can avoid eventually a situation which will arise where the spark and mix is off and you get a backfire through the intake.
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dontwantapickle
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Re: dual Weber manifold question

#3

Post by dontwantapickle »

Nobody ? I find it interesting that none of the Goldwing modifiers/customizers here on the forum has built their own.

ericheath: I have seen some pretty crazy single carb setups over the years.
Manifolds made from PVC pipe, sink drain pipes, radiator hoses, etc.....

I can tig weld, I'm pretty confident that I can fabricate something out of steel that will work better than anything I can find in the Home Depot plumbing aisle.
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Re: dual Weber manifold question

#4

Post by pidjones »

Search here and CGW. Lots of folks do the single carb experiment.
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dontwantapickle
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Re: dual Weber manifold question

#5

Post by dontwantapickle »

pidjones wrote:Search here and CGW. Lots of folks do the single carb experiment.
This is true.
However, I'm talking about DUAL IDF carburetors, perhaps I didn't make that clear.
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Re: dual Weber manifold question

#6

Post by CYBORG »

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Boxer4
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Re: dual Weber manifold question

#7

Post by Boxer4 »

I bought a set of manifolds that were made by the gentleman I bought them from. I have not seen the Randakk ones in person but I suspect they are almost identical. If I was building a set I would have them come out to the sides a little bit more to eliminate clearance issues with aircleaners.
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dontwantapickle
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Re: dual Weber manifold question

#8

Post by dontwantapickle »

Yes Boxer4, those are what I'm talking about.
That design is not too complicated to make.

I totally agree with building them so there is a bit more clearance.

I'm planning on doing some porting, and my initial calculations have those runners as being too long for my goals.
That's why I'm interested in seeing what others have done to possibly minimize the tweaking of the flow
that I will have to do.
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Re: dual Weber manifold question

#9

Post by gregforesi »

Well, there is simple...and then there is what at first look appears to be simple but it ain't. The guy Randakk used actually swaged the carb ends of the runners into ovals so they would be 40mm round when they hit the top plate and matched up with the carb bores. Nice trick that.
Other than that, each side is a couple of tubes with plates welded on.
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