1946 Indian Chief Preservation

[jlammers]

I'll check it with a dial indicator. It will be somewhat crude, but will give me an idea if I'm in the ballpark. What is a realistic tolerance, .003?

[T. Cotten]

Let's keep it simple, Jim...

You want it perfect.

And the manifold, too.

The easiest inspection is to 'machine' them clean and 'flat', and be done with it.

....Cotten
PS: Got a lathe?

[tfburke3]

I'll check it with a dial indicator. It will be somewhat crude, but will give me an idea if I'm in the ballpark. What is a realistic tolerance, .003?

Handy with a file?Some light passes over the holes will reveal the high spots.Cottens method is ideal but without lathe and fixtures a little carefull file work can be adequate.
Tom

[T. Cotten]

Handy with a file?Some light passes over the holes will reveal the high spots.Cottens method is ideal but without lathe and fixtures a little carefull file work can be adequate.
Tom

"Adequate" is subjective, Tom...

Please note that the shiny high spot is three-quarters of the flange:
flangcut.jpg

The low spot is the dull portion held back by the gallery stiffening the cast flange against the fastener stress.

Chalk up your best bastard and go for it.

....Cotten

[jlammers]

A very, very quick check tonight with the edge of a machinist rule shows that each mounting hole has burrs that need taken care of at a minimum. Once I do that, a better check can be done. Cotton is 100% right, the best way to fix it is to chuck it up and make some chips.

[T. Cotten]

A very, very quick check tonight with the edge of a machinist rule shows that each mounting hole has burrs that need taken care of at a minimum. Once I do that, a better check can be done. Cotton is 100% right, the best way to fix it is to chuck it up and make some chips.

After you have ground the manifold's flange flat, Jim,.

You could always lap it to the carb flange for a witness mark.

Won't cure anything, however.

....Cotten

[dukekleman]

After you have ground the manifold's flange flat, Jim,.

You could always lap it to the carb flange for a witness mark.

Won't cure anything, however.

....Cotten

Here are 3 photo stages of carb flange lapping I performed on a carburetor body that had been lathed prior in its life.
Surface area is crucial as we all know.
IMG_20241006_081427587~2.jpg
IMG_20241006_081831214~2.jpg IMG_20241006_082822782_HDR.jpg
Hope this is helps,

Duke Kleman

[T. Cotten]

Wouldn't tossing it on a lathe again have been quicker and easier, Duke?

The 'low' spot in your red box is the common result of fastener stress, and why 5/16"-18 bolts should be torqued to no more than 10 ft-lbs.

I also advise against thick or stacked gaskets, as it gives both flanges room to move:

ssmanifd.jpg


...Cotten
PS: With regard to surface area, please note how minimal it is between the top bolt hole and the counterbore.

Beware of ebay hero offerings that are compromised:
ITWGASK1.jpg

As well as castings themselves.... .
image_45592.jpg

[dukekleman]

Quote: Wouldn't tossing it on a lathe again have been quicker and easier, Duke?

I use my lap process to achieve the final surface finish I'm looking for.
If the Linkert carburetor body were a balanced component when installed in a lathe, I would use a particular cutter "speed" and feed to achieve the final finish I desire.
Being it's a counter weight in the lathe, I choose to get the final finish with this approach.

I typically use multiple steps/stages to arrive at the final result.
In this particular situation, lapping was all that was required to remedy issue at hand. It goes pretty quick actually...

Yes, those 3 fastener flanges designs require a great amount of attention. There are numerous ways things can go wrong in that design. Torque applied and heat can be very combative.
A great amount of attention to detail is required while simple things can be overlooked.

Duke Kleman

[T. Cotten]

Quote: Wouldn't tossing it on a lathe again have been quicker and easier, Duke?

I use my lap process to achieve the final surface finish I'm looking for.
If the Linkert carburetor body were a balanced component when installed in a lathe, I would use a particular cutter "speed" and feed to achieve the final finish I desire.
Being it's a counter weight in the lathe, I choose to get the final finish with this approach.

When you must cut dozens on a small lathe, You have a dedicated, adjustable counterweight:
CARBBALC.jpg

I typically use multiple steps/stages to arrive at the final result.
In this particular situation, lapping was all that was required to remedy issue at hand. It goes pretty quick actually...

I was taught, Duke, that a nice toolmark bites into and seals gaskets better; Even ground surfaces like a sharp, healthy profile, rather than a 'polish'.

Yes, those 3 fastener flanges designs require a great amount of attention. There are numerous ways things can go wrong in that design. Torque applied and heat can be very combative.
A great amount of attention to detail is required while simple things can be overlooked.
Duke Kleman

Myself, I blame the hundreds or thousands of cyclic expansion and contractions the assembly suffers in duty, aside from multiple callous installations and re-torques.

The 1" Models suffered less at the flanges, and 1½" Models suffered far worse.

....Cotten

[dukekleman]

Cotton,

An additional counter weight would be beneficial, no doubt.

Surface finish is something that varies based on variables. One of those would be the type of gasket material you are using. Bite, squeeze and slip...
It's proper RA finished is partnered with a particular gasket material.

Duke Kleman

[T. Cotten]

Cotton,

An additional counter weight would be beneficial, no doubt.

Surface finish is something that varies based on variables. One of those would be the type of gasket material you are using. Bite, squeeze and slip...
It's proper RA finished is partnered with a particular gasket material.

Duke Kleman

With a small lathe, Duke,

Its manditory. Note the cylindrical mass of steel opposite of the bowlstem.

It hinges at the top left to allow a clamshell assembly, closed by two forked tongues at the bottom, secured with a light aluminum nut.

I must counter-balance the manifolds as well, adjusting each on knife-edges.
CHFMNBAL.jpg
CHFMNCUT.jpg
PS: Sorry for the late edits; Please note that ususally each spigot must be re-chamfered before the tailstock livecenter sits true.

...Cotten

[dukekleman]

Cotton,

Good engenuity...
A well balanced component in the lathe aids greatly in any unwanted frequency in your cutting tooling.
This all contributes to a better finish on the component in the end.

Duke Kleman

[jlammers]

Take the set screw out of the detent (choke shaft stop), install spring and ball, press ball down in a notch, slide in choke shaft through detent and carb body, reinstall set screw….works for me….

And it worked for me, on the first attempt! Thanks for the tip! Now just waiting for a modern float to arrive so I can get it all back together and re-installed on the bike.

I also decided to order a new wiring harness for the bike. I'll save the original, but after a quick inspection there are multiple bare sections and it's all pretty fragile. There doesn't appear to be a whole lot to the harness (compared to my old Camaro for sure) so hopefully that's an easy job.

[jlammers]

Carb is back together! hopefully will get it back on the bike tomorrow.