741 Carb Bowl Condition

[JTR249]

Cotten suggested I post here a question about re-casting or treatment of the inside of a carburetor bowl for my 741 Linkert.
Take a look at the condition and let me know if this is normal wear. A couple of the pits are fairly deep and one is very close to the edge of the round passage where the bottom of the carb body passes through the bowl.
How would any of you proceed. I already ordered a replacement bowl, though I am interested to know your thoughts.
The first, smaller photo is the replacement bowl.
-JR 741 Replacement Carb Bowl.jpg 741 Linkert Carb Bowl.JPG

[ChiefTwoKicks]

Here's an idea... JB Weld is nearly impervious. Ive used it to patch threads on an original Indian fuel filter. Although I don't use the fuel filter anylonger, the patch (simply a swab around the threads, and a crack at the threaded hole), the patch never leaked. I ran it for nearly 5yrs, until I finally got around to locating another original filter. That was also back in the old days before all the new fuel blends made more problems than it anticipated. Solving one problem often creates different other problems. Roll the dice...

If the 741 fuel bowl was mine, I wouldn't hesitate putting the JB Weld on it !! Just be sure to clean the area you want to patch (I used acetone), maybe a very good carb cleaner.

Of course, the repair is only for a temporary fix. That could get you back together, while you search for a better specimen. Unless there are special specs for a 741 Carb bowl, they are pretty much all the same. Cotton would know if there are specific bowls for your specific carburetor. It might be Indian specific. I dont know. I dont know if 741 carb bowls are being remanufactured.

Good Luck, C2K

[T. Cotten]

I hope you ordered a sidevalve bowl, John?

That's an OHV bowl; If the pits don't go to daylight after blasting, I just seal inside the bowl with an isocyanate urethane, before grinding the top flat, and then lathe-dressing the bottom surfaces square to it.

.....Cotten

[JTR249]

Uh-oh. Well, I guess that's what happens when you don't question the description.
I saw "741" in the listing and thought I was okay. The diagram I used was in the combined spiral service/repair and parts list, so they did not illustrate the 741 in the section on carburetor assembly/dis-assembly and instead placed the 640 carb in the illustration. many sections in that book have charts that list similarities and differences side-by-side. Am I right?
So naturally when I compared that one with Greer's, I thought, that's odd, this one has an elevated part on the lip of the bowl.
So the correct bowl has a raised edge? like this--?
Linkert Side Valve Float Bowl.jpg
Thanks Chief and Cotten.
-JR

[JTR249]

Here's a better one. Is this one correct?
-JR
Linkert Carb Float Bowl 1.jpg Linkert Carb Float Bowl 2.jpg Linkert Carb Float Bowl 3.jpg

[T. Cotten]

Here's a better one. Is this one correct?
-JR

Yes, JR!

It needs prepped, of course; I'm not sure which manual you referenced, but it is common for wartime publications to focus on Scheblers, with some Linkert drawings showing hybrids.

....Cotten

[JTR249]

I was wrong about the manual. I have one of those re-prints of a service manual combined with the parts list. The seller spiral bound the whole thing. A really nice book, though most of the primary instructions are for the magneto set-up. Not the type of drive I have, but still useful.

What does prep involve? Mike at Into the Wilderness said the same thing.
-JR

[T. Cotten]

What does prep involve?

-JR

Kinda depends upon your equipment, JR....

And aesthetic expectations as well as function.

Rough-blasted aluminum is ugly, collects grime, and oxidizes faster, so embedded media can be removed with a soft power brush (Nylox, Adalox, etc.) to produce a brighter, smoother finish that stays clean longer. (I use a 14" wheel pulleyed down to a few hundred RPM.) And as I mentioned, the inside can be coated to encapsulate any remaining embedded abrasives, and protect against further corrosion. (ZAMAK Scheblers benefit from coating the bowlstem and bowlstem threads as well.)

Dressing the gasket surfaces as I mentioned is prudent "prep", and purists will want the cap, drain plug, and pivot screws to appear "cad".

....Cotten
PS: Yours appears to have been heavily sanded or even polished at some time, probably to remove hammer marks; Here I have sanded some away and re-textured with steel shot, before beading and the soft wheel brush.

HAMRMARK.jpg

I must add: If a piece is not thoroughly prepped, it cannot be properly inspected.

[JTR249]

I finally found the correct one and this one has a few extra parts. Still as you said, there is the prep work to be done. I had no idea all that went into a '41 carb.
My motor is the learning model I cobbled together from all kinds of places--a standard bore 741 distributor ignition powerplant.
Here is the one I selected. Have you ever used New Metal to fill the pocks in the outside? -JR
Linkert Carb Side Valve Float Bowl 1.jpg Linkert Carb Side Valve Float Bowl 2.jpg Linkert Carb Side Valve Float Bowl 3.jpg

[T. Cotten]

...I had no idea all that went into a '41 carb....

We have only briefly addressed the bowl, and none of its working parts, yet, JR,..

Prepping the 1/4"-32 threads should be addressed,

Just wait until you get into the body.

..Have you ever used New Metal to fill the pocks in the outside?

Not familiar with it, JR,
But then I never had a customer feel that putting a bandaid on a beauty mark was necessary.

....Cotten

[JTR249]

741 Carb A BMB.jpg 741 Carb B BMB.jpg Wally Brown sent me what appears to be an excellent condition body. By prepping threads, do you mean some type of lubricant or thread-lock?
-JR

[T. Cotten]

Depending upon their condition, JR,...

They may require only a good brass bore brush for cleaning, or to be chased with a tap if stressed, or a full replacement with an insert if boogered.

Your pics left out the vital model stamp; Is it an M741, or an M741-1?

....Cotten

[JTR249]

Are you kidding me? What's the difference? Mag model or distributor? I didn't even know about this one.
This is exactly why this one is just to learn from and you have schooled me most abruptly.
Thank you, sir. This one is an M741-1.
-JR 741 Carb D BMB.jpg

[JTR249]

This one does not have any signs of damage. All the threads look clean and good. He will usually tell people if there is any damage and is always honest about cost.
How's this as an answer to my own question above:

"In the context of carburetors, "M741-1" and "M741" likely refer to the same basic carburetor model, with the "-1" signifying a slight variation or modification, usually relating to internal components like jet sizes, needle and seat configurations, or specific adjustments made to suit a particular engine application; essentially, an M741-1 is a slightly tweaked version of the standard M741 carburetor.
Key points to remember:

• Base model: Both "M741-1" and "M741" are considered the same base carburetor model.
• Minor variations: The "-1" signifies a minor difference in internal components or settings, potentially impacting performance characteristics.
• Manufacturer specific: The exact meaning of "-1" can vary depending on the manufacturer, so checking the specific product documentation is important for precise details."

I never knew Google knew Indians!

-JR

[T. Cotten]

You can tell that was written by AI, JR....

By what it doesn't know, such as the manufacturer, and that the difference was venturi size, which is hardly a 'slight variation' when it comes to performance.

Common sources cite the M741 with a tiny 3/4" venturi, and the M741-1 with 13/16", the same as used for 80" Fours.

(However, I have a L&L spec sheet that says 13/16" for the M741, but also an impossible 7/16" float setting!)

....Cotten