3-D Printing an Obsolete Part (Intake Manifold)

SMSW

Joined
Sep 4, 2013
Messages
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Location
Cleveland
Bike
2010 ST1300
In the early '90's I acquired a bike in milk crates and restored a T3 Moto Guzzi (this is posted here because my question is not really bike specific). At that time, my neighbor was an amateur racer and restorer of Guzzi's, and he worked with me putting the bike back together. At his suggestion we replaced the original carbs with DelOrto PHF30's, and the intake manifolds with a curved manifold (pictured below) from another model Guzzi. Fast forward 25-odd years and these rubber manifolds, (which were used on one model bike for two years (and not a very popular model, I might add) are now made of unobtanium. Correction. there is one side available in Europe for around $100.

I'll be restoring this bike again this winter, which will be mostly cosmetic, except for tires, battery, perhaps new cylinders, and an upgraded alternator. (The cylinders are another story.)

These manifolds are relatively simple, and I can get help using SolidWorks to create computer file models of the manifolds (they are side specific). I can then use the facilities at my nearby alma mater to print new left and right manifolds. Note that the original pieces, simply bent hard rubber couplings, clamp onto an aluminum spigot on the cylinder head and receive the carb's spigot at the other end.

For those who have played with 3-D printers, do you have any suggestions for the material I use? Any thoughts regarding how hot a motorcycle's cylinder head (air cooled) might get? I would expect to receive some guidance on the material at the university, but I also think they would not have much experience in answering my second question.

I will add, there is a company in Italy (I think), that upon receiving original parts will do a short production run manufacturing new parts in the original material. This would make sense for a very valuable and rare bike or car, but certainly not for a potential daily rider.

Manifold 2.jpg

Manifold 1.jpg
 

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I would try Harper's Motto Guzzi near Kansas City. They might have a work around.
Those air cooled heads are going to get hot.
 
Wouldn't a work around with available parts be easier, unless of course originality is very important. I have no idea if these would fit but there are parts out there that MAY do the job.
Could coolant hoses be altered to do the job.
Good luck.
Upt'North.

www.ebay.co.uk

4pcs Motorcycle Carburetor Intake Manifold Boots for Honda CB750C Custom 80-82 41814240671 | eBay

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I looked for rubber plumbing connectors, and found a few things that might work. I see you need two different opening sizes, but I have no idea of the sizes needed. Here is what I found on the HD site:

Here's a 90, perhaps the right size could give you two usable opening sizes if cut:
www.homedepot.com

Fernco 2 in. x 2 in. PVC DWV 90-Degree Mechanical Flexible Elbow PQL-200 - The Home Depot

Bring convenient connections to your pipes using Fernco PVC DWV Mechanical Flexible Elbow. Compatible with cast iron, steel, plastic, copper.
www.homedepot.com

They also come in straight reducing couplings, if straight is a possibility:
www.homedepot.com

Fernco 2 in. x 1-1/2 in. DWV Flexible PVC Coupling P1056-215 - The Home Depot

Fernco - 2 in. Drain Waste and Vent x 1 1/2 in. Drain Waste and Vent Flexible Coupling - This bendable attachment is compatible with a wide variety of piping. Product resists corrosion and offers an efficient
www.homedepot.com

They don't show 45s available, but other places do; again, you have to look for appropriate sizing:
www.marsupco.com

''VHT'' 45 degree Elbow - Blue

Serving St. Augustine & Northeast Florida's Commercial and Recreational boating needs since 1946! The best place for all your Marine Supplies and Fuel!! Located in Historic Downtown St. Augustine, Florida.
www.marsupco.com

National Supply Direct - Your Marine and HomeGoods Superstore Wet Exhaust Hose - Plumbing - Engine and Plumbing

National Supply Direct - Your Marine and HomeGoods Superstore
nationalsupplydirect.com nationalsupplydirect.com

Silicone 45

Shop here for your silicone 45 degree elbow.
www.siliconeintakes.com

KBJ-45L-H-100A | K Black J 45° Elbow | Ito Tekko | MISUMI

K Black J 45° Elbow of Ito Tekko,KBJ-45L-H-100A. Check out the variety of configurable, K Black J 45° Elbow products of Ito Tekko,KBJ-45L-H-100A. MISUMI has other mechanical components, Press Die, and Plastic Mold products available. MISUMI offers free CAD download, short lead times, competitive...
us.misumi-ec.com us.misumi-ec.com
www.ebay.com

Donaldson P105543 Heavy Duty Rubber 45° Elbow (Inner Diameter: 64mm / 2.5") | eBay

Donaldson P105543 Heavy Duty Rubber 45° Elbow(Inner Diameter: 64mm / 2.5")Flexible rubber adapters and elbows have smooth radii and inside surfaces to minimize flow resistance within the air intake system. Rubber adapters help to absorb vibrations and reduce intake noise level.Specifications: ...
www.ebay.com

Jamestown Distributors

www.jamestowndistributors.com www.jamestowndistributors.com

45 Degree Rubber Reducer Elbow

45 Degree Rubber Reducer Elbow.
puredieselpower.com
 
I'd start by looking at the materials available for 3D printing and then select the most likely to succeed. Once you have the 3D model you could try different materials.

www.martins-rubber.co.uk

Choosing the Right Rubber Materials for Your Application

Selecting the right rubber materials for an application is crucial. Martin’s Rubber explains the importance of material selection in rubber engineering .
www.martins-rubber.co.uk www.martins-rubber.co.uk
 
There are several alternatives that I can use, i.e. original T3 manifolds and carbs, or manifolds from the later model LeMans, etc. The problem with these is I would have to modify (cut) the sheet metal of the side covers. I don't want to do this. Originality is not of paramount importance. I've upgraded the ignition to a hall effect sensor in the distributor, eliminating points, am considering a larger alternator, have an outside oil filter (imagine that, MG's of this vintage used a spin on oil filter inside the sump - IIRC, 18 screws to drop the sump and a new gasket to replace the oil filter). If I use the alternative manifolds listed above, new problems crop up, namely clearance issues with the tank, carb cables and air filters, not to mention knees (the riders).

@cjames431, I've checked with Harpers and all of the old Guzzi parts folks. The response is inevitably, used manifolds will be in iffy condition, and old stocks of the OEM parts are long since gone. I've posed this problem on the WildGuzzi website. I'd recommend their Restorations forum to some of you who have fixed up an old bike. There are a few guys who post lengthy threads of their restorations that are breathtaking.

Thanks to all for your suggestions, I'll look into all the leads suggested.
 
Without seeing the other side, is it possible they are identical except for the screw? If they are then you could buy 2 and the only difference would be a screw on the bottom on one side.
 
Byron said:
Without seeing the other side, is it possible they are identical except for the screw? If they are then you could buy 2 and the only difference would be a screw on the bottom on one side.
Click to expand...
Not exactly identical. One carb ends up with its intake slightly ahead of the other due to a tighter bend in the manifold. The KnN air filters (cone shaped), are massaged slightly to fit in the available space under the seat and in front of the battery. Once one is modeled, relatively few dimensions would have to be changed to yield the other, and printing two would not be much more difficult than printing one. Where are the Enterprise's replicators when we need them?
 
Might be worthwhile to take your boots to an auto part store and match a radiator hose with a bend of nearly the same angle, close enough that it won't mislocate your carbs too much or cause a crimp....and same inside diameter at the two ends of course.

I'm not familiar with a printable material with the flexibility capable of sealing at the ends. If you want to continue along that path, print the basic part to the modeled boot...leaving enough id at the ends to insert a softer seal. A ring seal could be cut from a radiator hose.
 
I've not dabbled with printing flexible filaments like TPU (thermoplastic polyurethane), but I know it takes a different setup for a 3D printer. Plus, for any material, it needs to have a high enough print temperature to also resist stretching and creeping at the bike's operating temperature. TPU is probably right at the limit. There are other flexible plastics but are even more difficult to print than TPU.

The piece design appears pretty simple by itself and quite printable. The main issue with any printed part under stress is to limit that stress across the weak interlayer adhesion as it can break easily. Also, it is hard to ensure a 100% airtight part right off the print bed. Either the wall must be made a little thicker or you must apply a sealing coating afterwards.

However, what would be your best bet is to make a 3D print of a mold to make the parts from a poured-in or injected thermosetting plastic. Here you don't need to worry about heat tolerance or air leaks, only compatibility of the printed plastic with the polymer you want to use (likely a neoprene or butyl rubber).
 
Since the required abilities are low deformation, heat-, fuel- & oil-resistance I would look into making silicone molds and vulcanizing rubber...
Processes used in jewelry or denture making come to mind...
Vulcanizing will also create a proper bond on the threaded (brass) sleeve needed as syncing port...
Maybe you can print a 3D master to cast the 3-piece silicone mold on it (or 6-piece as you've a left & a right part), but as far I understand is there no way to 3D print rubber per se...

Found some good information on elastomers... don't know about mechanical and thermal resistance though...

all3dp.com

3D Print Rubber: Is Rubber 3D Printing Possible?

As designers continue to grapple with the possibility of 3D printing rubber, we tell you whether it is achievable or not and go into detail discussing alternative rubber-like 3D printing materials.
all3dp.com all3dp.com
 
Be sure to update this thread with what happens. I'm curious. On the one hand, how many would they sell? On the other, how hard is it to create a part if they keep the originals on hand to make more as needed? I don't know and I don't know if that's how it works, just wondering.
 
I was going through old posts and stumbled across this thread. SMSW, were you able to find/make the parts? I'm actually doing more with TPU now. If you're still in need and have the parts to replicate I might be able to reverse-engineer them...might.
 
jdmccright said:
I was going through old posts and stumbled across this thread. SMSW, were you able to find/make the parts? I'm actually doing more with TPU now. If you're still in need and have the parts to replicate I might be able to reverse-engineer them...might.
Click to expand...
Thank you, but a few months ago, I sold the bike. I posted this elsewhere, but after putting a lot of work into the bike, I took it for a ride. Bottom line, it rode like the 1976 bike it is. I did not like it even after a few rides. I've been spoiled rotten by the ST and now by my VStrom. I decided to sell it and was extremely fortunate that a guy from Savanna, GA who loves Guzzi's saw my ad and gave me a call. I did most of the heavy lifting, but he continued and corrected the last major item the bike needed. My T3 had chromed bores on the cylinders and many of these begin to shed flakes of chrome after a while. Those hard flakes will chew up the engine if ignored. My bike had only 17,000+ miles on it and showed none of the symptoms. The new owner has replaced the cylinders and the bike will now go an easy 100 to 200k miles.

As it turns out, the intake manifolds are sort of available...but they cost around $65 each and most are in European countries. No idea how hard they are, but mine were ok for now and should be good for a while.

You can see a partial picture of the gas tank in my first post above. This is the bike when I sold it:

IMG_5602.jpg
 
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