C-200 cafe'....My project bike.....

[Weldangrind]

I'm sure that I could convince my buddy to TIG it, but the logistics are a challenge.

[66Sprint]

Thank-you for the kind thoughts...
It may come to that if the shops around here continue to refuse to even attempt it...(still looking for the "right" shop and/or the right price).....
I've already ordered/purchased another manifold in case my geometry calculations are way off, and the cuts prove fatal to the one I now have...(a spare never hurts)....LOL...


Even one step at a time, I'll get there eventually..... :wink:

[Weldangrind]

Do you have a MIG welder? Have you considered fabricating a new intake tube out of steel?

[66Sprint]

Yes,....and Yes..... But somehow that interferes with the aesthetics I mentally picture......
IF (big if) I can manage to get a mandrel-bent steel U-bend with a 1" (26mm) interior diameter AND manage to weld it so it looks decently, AND I spray paint it with Dupli-Color "cast finish aluminum" to re-achieve the sandblasted texture, I might be satisfied with it as far as appearance.....
Here's a pic of the two assemblies....

While I could add the reinforcing "rib" and probably get closer in appearance if I do make it up in steel, my problem with attempting this is the steel would "hold" more engine heat, preheating the fuel/air charges somewhat.....

Red lines are from my "eyeballing" to predict the cut line.... :oops:

Yes, I DO tend to overthink every little detail.....

[66Sprint]

Weld, After careful consideration and sourcing the materials, I think you MAY be on to something....
I can get 1" OD mandrel bends easily (and fairly inexpensively)......
slicing it lengthwise with a hacksaw and inserting a shaped piece of sheet to spread the gap will expand it to an almost perfect 26mm size and create the reinforcing rib...(two birds with one stone)... I am considering brazing the bits together rather than welding as the seam flow will smooth the internal surface as well.....The flanges will be 1/8" sheet with 3/4" OD tubes 7/8" long (1/4" bore) to replicate the casting at the head end....With similar fabrication at the carb end to emulate its looks......

It dawned on me I can counteract the slight heat transfer by enrichening the jetting slightly....and I believe a 10mm high insulator is available for the manifold to head joint....

Opinions of this plan?......

[Weldangrind]

I think that insulators on either end will negate the heat issues with steel.

That said...

If you can braze, can you just braze the aluminum to meet your needs?

[66Sprint]

Learning something NEW...I did NOT know aluminum COULD be brazed.....Special flux or rod necessary?
(To me, brazing means brass rod and Borax flux.....)

[Weldangrind]

This is an area where I'm a little weak, but I know that aluminum can be gas welded. I also believe that aluminum can be brazed, but my Haynes Welding Manual says that brazing is meant to work with a mechanical joint (like an overlap), but not a butt joint. It also says that brazing is as strong as welding when done properly, although the parent metal does not flow into the puddle.

A copper / zinc filler rod is commonly used for ferrous metals, but I haven't yet figured out what is used for aluminum (aside from what the book calls a special aluminum brazing rod). I recommend that you seek the guidance of your local welding supply shop.

Do you have an oxy-acetylene setup?

[66Sprint]

Yes,.... and also an Acetylene/air set-up I use for making jewelry (Silver soldering),... of course the flux wire MIG , (set-up with the option of a CO2 or CO2 /Argon shrouding gas)......Plus the stick welder.....

[Weldangrind]

Then you should have all of the hardware you need. The good news is that the China intake tubes are cheap as chips, so one can afford to experiment on them a bit. Looking forward to your experiments in brazing / welding.

[66Sprint]

We'll see....I ordered another manifold that already has the 45 degree upwards curve.... May require 1/2 and 1/2 and some careful fitting.... The steel option is looking better and better....LOL....

[FastDoc]

I know it's primitive, but what about a hacksaw, a short rubber connector, and 2 hose clamps? You could get any angle you want.

[66Sprint]

Well Doc....
I'm sure it would/could run the engine reasonably well (IF one keeps the joints "tight" so there aren"t any "steps" in internal diameter in them).....
BUT, the manifold is also the primary support for the carb.....Honda has even "added" an external "rib" to stiffen/strengthen the stock manifold (which has easily twice the wall thickness of the "cloned" copies for that part of the task), and I have to believe the Honda engineers knew what they were doing....
While I don't believe that there would be much flex to such a rubber jointed assembly, I think there might be enough to give problems eventually....
Of course, my main concern after proper running is the asthetics, and since I am somewhat stubborn (read that as Anal), I just can't bring myself to "cobble" it up......SO, I'll do just that with the rubber joints until I optimise the way it runs, then reproduce the shape in steel with the added rib...Eventually, I'll take that steel manifold to the local high school's metal shop and attempt to have a cast aluminum version made at their foundry...Unfortunately, welding is taught at a separate vocational school (to which I have no access) or I could shortcut this entire process....
I try to make every part so anyone who isn't intimately familiar with that model would think it's "factory" original....(Did I mention that I'm a bit anal about fabrication?)... LOL...

[Weldangrind]

You're preaching to the choir, brother. While my work doesn't always show it, I can appreciate your style.

I'm really hoping that you gas-weld the intake. This guy is a little corny, but he's really talented:

[FastDoc]

I understand and respect your point, I was just sayin' :wink:

Believe me I can get a Silver Medal in the OCD Olympics on my worst day.