I can't wait for the fancy welded manifold so I'm making one from PVC

[brianinpa]

opcorn:

When I go to the big blue or orange stores to look around, I like to take one of these so I can sit for a while as I think things through... :smilie_happy:

Oh, and I am a vintage tool guy too, so how about a better photo of the drill press!!!

 

[mcgovern61]

Brian, you keeping that on your trailer while camping now? :smilie_happy:

 

[mcgovern61]

Well, for those of you that need some controversy and nay-sayin....

"It will never work"......... :deadhorse:

"You need heat....I'm cold.....I mean........you need cold heat.........."

"Those air passages are too small/big/sideways/........."

"I told you it would never work.....I mean, who ever heard of something like this workin........can't happen.....not on my watch........."

:smilie_happy: :fishin: :wave: opcorn: :yahoo:

OK, it is out of the system, so go ahead a build!

:smilie_happy:

 

[dan filipi]

Yeah it's fun to joke and all and as far as questioning how this build will work out.....I sure won't because I've been surprised too many times already what does work so I'm quietly watching the build come together.
This is not all that radical either.
My only question is the gorilla glue holding metal to plastic.
I've never tried it so I don't know.

 

[chuck c]

Gorilla Glue is wickedly strong stuff. I'm not too worried about that, I'm more concerned with how it handles vaporized gasoline. Polyurethane is not really gas-proof. I'll test it before I take any long trips! If it doesn't hold up there are plenty of other options like JB Weld or make that flange out of PVC and use PVC cement.

 

[chuck c]

I bought a couple of 45 degree pre-bent sections and then spent a couple of hours cutting them to try to get a good fit. They are a large radius of about 18" with a few inches of straight on one end. I thought I could cut them to give me just 7 out of the 45. Nothing I did came out very good because I have the curved portion inside either the connector or the rubber portion of the intake tube. The bend would have to be in the middle leaving both ends straight for them to seat correctly. Tomorrow night I'll dig out the heat gun and try to bend a few. In the meantime I shoved it into place to see how it looks and it's not bad with just straight pieces. There's enough "give" to let it most fit. They aren't seated very well so I think it is worth it to try bending them.

If bending doesn't work well I could make a saw cut say, 3/4 of the way thru the tube, bend it, then glue it. I don't want to create another possible leak point.

One more magic number: 450. That's the center distance between the right and left intake ports in the heads, as best I can measure it. A bit if research says acetone is the only thing that affects Gorilla glue once it's cured.

 

[chuck c]

You can see the carb sits very far forward. It could move back a full inch and still have clearance from the frame. I think I need to do that.

The rubber on the intakes is rock hard. I'm afraid I'll split it forcing the PVC in.

Any suggestions on an air cleaner?

PS I'm under no delusions this will work well. I'm sure a well designed one would work much better. I'm enjoying the challenge of making one that works for about $40.

 

[slabghost]

Might want to file the runners down a bit so they fit easier. I'd just put a pod air filter on it if it were mine.

 

[chuck c]

There's going to be so little left of that box when I get done it's got me rethinking it. If I used a piece of plain old round it would be easy to drill holes at the 7* angle and could be made long enough to not need those offset connectors that I fear are restrictive. I'd only need a flat plate in a small area to mount the carb. Hmmmm.

 

[brianinpa]

Have you decided on the baffle for the inside yet to help prevent the two cylinders from running lean?

 

[joedrum]

it is very easy to thread pvc pipe to accept the threaded fitting you are using ...when i farmed ... i did this a lot and it worked great and was easy to seal ... it was easy to make your own tapp too from a threaded piece of piece of pipe ...by just cutting slots in it so waste cutting can have place to go .....

so this idea you have is totally doable without expensive tooling ...so if one was going to use stock intake horns witch are square to the centerline of bike this would work great .....i am not avocating you stop doing what your doing just throwing info out that you might use to think on ....

 

[chuck c]

Now that I will probably relocate the carb closer to center that shouldn't be needed.

 

[dan filipi]

chuck c » Tue Sep 16, 2014 3:12 am[/url]":27o9gv4i]
There's going to be so little left of that box when I get done it's got me rethinking it. If I used a piece of plain old round it would be easy to drill holes at the 7* angle and could be made long enough to not need those offset connectors that I fear are restrictive. I'd only need a flat plate in a small area to mount the carb. Hmmmm.

I don't think the offsets will be a problem.
It's looking good.

 

[slabghost]

With the results of all the other builds and considering their different designs. I really doubt the restrictions in the offsets will make any noticeable difference.

 

[Ansimp]

slabghost » Wed Sep 17, 2014 1:39 am[/url]":3210zawo]
With the results of all the other builds and considering their different designs. I really doubt the restrictions in the offsets will make any noticeable difference.

+1
Also on Joes slotted threaded pipe tap. I use that system on 1 1/2" fittings in poly tanks :good:

 

[canuckxxxx]

Questions: :headscratch:

What is the "fancy welded manifold" you can't wait for?
How did you do that very nice drawing in post #1?

Thanks
Brian

 

[dkl]

The four intakes look like they are set close to 1/2" above what will be the bottom of the manifold. Gas should not be allowed to pool in the manifold, could be dangerous.....and this comes from a PVC guy. The picture may be misleading.

 

[joedrum]

dkl » Tue Sep 16, 2014 6:40 pm[/url]":31jjgz2x]
The four intakes look like they are set close to 1/2" above what will be the bottom of the manifold. Gas should not be allowed to pool in the manifold, could be dangerous.....and this comes from a PVC guy. The picture may be misleading.

good point but floor can always be filled also .....

 

[tom foreman]

wow,very kool ... :clapping: :music:

 

[slabghost]

dkl » Tue Sep 16, 2014 5:40 pm[/url]":324d6a35]
The four intakes look like they are set close to 1/2" above what will be the bottom of the manifold. Gas should not be allowed to pool in the manifold, could be dangerous.....and this comes from a PVC guy. The picture may be misleading.

Pretty much all the production manifolds for carbs have a rough bottom to hold any puddling fuel. It will evaporate and join the fuel charge once the motor warms up. Better to have it pool in the plenum than get into the cylinder as a liquid.