Intake manifold questions and comments

Shaun Chandler

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Well I'm about to get an intake maniflold laser cut along with some stuff for some other jobs I'm working on and wanted to start a thread to get some comments on them.

I've drafted up two types. The first is just like the stock except not rubber it will be 3/8 aluminum with an aluminum pipe welded in and I will use either reinforced silicone as the boot or mabey viton tubing. I haven't sourced the rubber yet so not quite sure. Then of course it will use stainless clamps. The picture of aluminum intakes I posted below is the 650 ones I just ripped the picture off of google.

Here is my first question. Why are there no vacum lines in this version from the xs650. You would need them to balance the carbs and if you used a vacum petcock (which I'm not sure the 650 has)?

Alright so my second design is a one piece intake I drew up and I've attached a picture of the scale paper template I printed off. It will also be made of 3/8 aluminum. Because I didn't want to cause a hot zone in between the carbs around the cylinders I made those cut outs in the middle to allow for air flow.

I plan on putting vacum lines on both styles I was just kinda curious why the 650 intakes don't have it. I just have to source some of those little flared vacum lines I'm sure they would be cheap enough not to bother purchasing them. Anyone know what I would call them aside from a flared copper nipple? Because I'm getting nowhere finding them yet.

I just wanted to put my ideas on these out there so I could get some opinions on what I'm doing. By all means tell me if something sounds stupid I just wanted to make a original looking intake so I'm leaning towards the one piece.
 

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You could try some barbed hose fittings; they are cheap and come in all sorts of sizes and styles. You can even get some with threads and such.

A "single barb hose fitting" looks the most like the original design.
 
Thanks Fubar. Hopefully have something real next week I can post up.

BC- Ya I considered hose barbs the problem with those is the smallest I could likely use would be a 1/8 NPT thread and that requires a Q drill which is around .332 inches. Since my flang will only be 3/8 thick (.375) that leaves almost no meat.

I think I'm going to have to get creative and probably flare my own copper pipe nipples and press them in.

Shaun
 
The later XS650s have vacuum petcocks. The reason those intakes don't have vacuum ports is they are meant to be used with Mikuni VM carbs and most people use the VM's that have the vacuum ports in the carb bodies.
 
Hey Drewpy

Lot of stuff on that site I just checked it out. They have barbs but I don't see myself being able to use them. If you look at the picture of the intake there isn't much room left on either side of the original vacum line (around 90 thou) and because I want to make this usable with stock air boxes. I can't make the flange any thicker since there will just be enough room for the clamps.

I have the flaring tool I may just have to make the copper piece and press it in.

Hey look you can see all the scars on my hands from the grinders that have taken a bite out of me :doh:

Shaun
 

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Oh I think I see what your saying drill and have two holes intersect? Then I can put a 90 barb on the front. Yup I can do that I have a mill, hell I could do that on a drill press. Great idea Drewpy I never thought of that.

I think I would have to change the shape of the flange to allow room as there is really just enough room for me to weld in the stub pipes.

Shaun
 
You will be glad to know Charles I'm just waiting for the quote from my laser cutter. Hopefully they don't drag there feet to much. My orders from them are usually small potatoes but they are usually quick.

Shaun
 
Alright so I'm getting some manifolds laser cut and I was hoping I could mabey get some assistance from the good people of the forum.

Once I finish making my manifold I considered putting it up for sale in the classifieds section of this great website.

I'm posed with a small problem though I want to make a part that would be usefull on many different bikes of our type. Different years and such but I only have two motors. One is a 78 and the other a 81 (sohc).

I'm attaching a pdf of my intake with some dimensions on it and I had hoped some people could check the dimensions against their motors, if possible I realize your not going to take your carbs off for me:wtf: .

All the dimensions are in inches. I would like to be able to offer these in the future but I have no way of checking my dimensions against other models and model years.

Thanks a million

Shaun
 

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Well I still haven't got rubber tubing yet I think they will be around 100 thats just a best guess right now. I've ordered the parts to be cut so in the end if you don't want them no hard feelings. This is a rather small market I'm sure but I'll put what I come up with out there and see if there is interest.

Shaun
 
Well I finally got my intakes back from laser cutting thought I would throw up a couple pictures. I'll probably be able to get one welded up this weekend. Still waiting on rubber hose for the boots. Wanted to get Viton tubing but I'm buying such a small amount that no one will talk to me for pricing. Moving onto large nitrile fuel transfer line hopefully I'll have it order tomorrow.

Take a look at the pics and tell me what you think. I cut both designs. I'm kinda partial to my own one piece design.

Shaun

My one piece will only work on a large scale if the center to center distance on the intake ports is the same for all bikes. SOHC only I don't have a DOHC to measure off of
 

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Well I finally got my intakes back from laser cutting thought I would throw up a couple pictures. I'll probably be able to get one welded up this weekend. Still waiting on rubber hose for the boots. Wanted to get Viton tubing but I'm buying such a small amount that no one will talk to me for pricing. Moving onto large nitrile fuel transfer line hopefully I'll have it order tomorrow.

Take a look at the pics and tell me what you think. I cut both designs. I'm kinda partial to my own one piece design.

Shaun

My one piece will only work on a large scale if the center to center distance on the intake ports is the same for all bikes. SOHC only I don't have a DOHC to measure off of

I'm leaning towards the two piece. They look mighty nice!

For connecting tubing/hose, what about radiator hose from local auto parts store? Also, Pep Boys sells silicone tubing. Maybe try that?
 
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