741 Carb Bowl Condition

[JTR249]

Service Shots 153 Linkert Carb Spec Sheet.jpg Do you think this has anything to do with the Service Shots 153 stating the opposite of what we previously discussed regarding venturi sizes?
Here's a photo of the page.
Do you think I need to try a fit of a 3/4" venturi to see if the fit is tighter?
The Service Shots page had the specs for venturi flipped around. My carb is an M741-1 and so I bought a 13/16" venturi as you suggested.
I will look in my spares and see if I have one and let you know what I see.
-JR

[T. Cotten]

The 'fossil record', JR,...

Suggests that's just another 741 typo.

The fit of the venturi within the body has little or nothing to do with the venturi's bore ("choke"); It has more to do with whatever ZAMAK was poured that day, and the decades of 'seasoning' thereafter (That's why swaging venturies is an art, and not a science).

A three-quarter would be great stoplight to stoplight, if there is no leakage around it or the nozzle spigot. You might even merge with Interstate traffic if you are brave.

Graciously, the 1" Models that crossed my benches were usually in much better condition than larger Models.

....Cotten

[JTR249]

Okay. I thought that's what you said earlier.
I tried to fit the throttle disc and it will fit inside the bore, though is very difficult to get it to move.
I ordered a 1" and a 1 1/2" disc as well just to see if there is any difference in free movement. If not, I will try what you suggested and try to file the edge.
Is there a special file or any old type that is in the barn for metal blade implements?

The choke disc fits fine, though the arm is very stiff to move. This is one of the few original parts on the carb.
Thanks again.
-JR

[T. Cotten]

Okay. I thought that's what you said earlier.
I tried to fit the throttle disc and it will fit inside the bore, though is very difficult to get it to move.
I ordered a 1" and a 1 1/2" disc as well just to see if there is any difference in free movement. If not, I will try what you suggested and try to file the edge.
Is there a special file or any old type that is in the barn for metal blade implements?

The choke disc fits fine, though the arm is very stiff to move. This is one of the few original parts on the carb.
Thanks again.
-JR

Your throttledisc was 1 3/16", JR,...

Measured at the shaft axis. A 1 1/2" disc will be 1 9/16", and never used by Indian.

When did I ever suggest filing upon a throttledisc?

Not that it can't be done:
PennyThrottle.jpg


....Cotten

[JTR249]

I thought you said in an early post in this thread a good shop could remove metal if the disc does not fit? Okay--not filing, but removing is a different process.
Sorry for the mis-phrasing of what I meant.
I just measured my throttle disc and it is a #11 (from the used parts purchased online) and measures 1 and 2/16" across the mounting holes.
If this one does not fit as I described, what should I use?
-JR

[T. Cotten]

I thought you said in an early post in this thread a good shop could remove metal if the disc does not fit? Okay--not filing, but removing is a different process.
Sorry for the mis-phrasing of what I meant.
I just measured my throttle disc and it is a #11 (from the used parts purchased online) and measures 1 and 2/16" across the mounting holes.
If this one does not fit as I described, what should I use?
-JR

I believe, JR,

I was referring to machining an oversized disc from a larger spent 1¼" or 1½" disc, or from scratch, as is necessary for oversized bore repair.

You wanted a 12°, and unless your bore has been honed oversize, it should be 1.1875", or perhaps a half-thou less.

We assume you installed fresh throttleshaft bushings for a fresh shaft?

....Cotten.

[JTR249]

The bushings were already in the body, looked very clean and appeared to be in good condition. I will have to double check because the bottom is ever-so-slightly wobbly.
I was looking at the throttle disc again, pulled my wet/dry sand paper out and went over everything generously and what do you know? The disc finally fit. I also sanded the shaft.
Here's a photo. Of course I'm still waiting on the bell crank and parts with that. I also have not fitted the cable swivel assembly.
-JR
M741-1 Throttle Disc Fitted.JPG

[T. Cotten]

The bushings were already in the body, looked very clean and appeared to be in good condition. I will have to double check because the bottom is ever-so-slightly wobbly.
I was looking at the throttle disc again, pulled my wet/dry sand paper out and went over everything generously and what do you know? The disc finally fit. I also sanded the shaft.
Here's a photo. Of course I'm still waiting on the bell crank and parts with that. I also have not fitted the cable swivel assembly.
-JR
M741-1 Throttle Disc Fitted.JPG

So they are not fresh bushings, JR?

If you can feel slop on the fresh shaft, they are sloppy. Usually the top is worst. If they are sweet, don't fix them.

Ideally, for flow and performance, like a motor valve, you shouldn't round off the edges of a throttledisc.
Ideally.

Your carb looks ready to disassemble and prep; Please grind the manifold flanges flat.

...Cotten

[JTR249]

Thank you very much, Cotten. I have learned more than I ever knew before about this type of carburetor in these 5 threads.
I have taken careful notes and will use them for future reference and still need to read all of Paul's rebuild thread.

Do I have the carb assembled correctly with the float needle assembly on the choke lever arm side?
I have seen other Linkerts with different configurations.
-JR

[T. Cotten]

It's hard for me to tell much from your pics, JR,..

Except the throttledisc is upside-down; The degree stamp should be on the right side of the shaft.

Please note how the beveled edges of the disc will then close 'flat' against the bore wall.

The only other Linkert bowl alignment is the inline OHV, which is capped by the carb body. (WLA folks often have fits installing their sidebowls any way but perpendicular to the body, most likely due to repop fuel lines. Unfortunately, this often leads to the float hanging up upon the bowlstem, and overflowing.)

.....Cotten

[JTR249]

Ok. The 11 stamp goes on the right side facing this end (#67 and 68 above)?

Thanks.
-JR

[T. Cotten]

Ok. The 11 stamp goes on the right side facing this end (#67 and 68 above)?

Thanks.
-JR

I believe that's in the service manual, JR,

All Linkerts and Scheblers went to the right (except DCs' went on top), or else the bevel doesn't mate the bore.

And properly, it should be a twelve, but it would probably run anyway!

....Cotten
PS: Beware of some abominable 1" discs produced I believe, in Czechoslovakia.
popGDISC.jpg

[JTR249]

Got it.
Those diagrams are not easy to interpret.
Yes, 43-4 number 4 in the assembly procedure.
Thank you.
-JR