Leather question

[T. Cotten]

I couldn't find an appropriate section of the Forum for this question, so I'll ask it here...

I am about to punch out another batch of H model airvalve leathers. What sort of leather would best resist heat and gas fumes? "Vegetable-tanned", "chromate-tanned", or what?

Thanks in advance,

...Cotten

[AdminGuy]

I don't think it matters. Thickness may be the only consideration.

[T. Cotten]

It seems to matter.

My preliminary tests show that modern leather immediately gives up it dyes to produce an ugly mess when douched with gas. (Let's see how that gets through the cybercensor.)

Some ancient belting material appears to be very much more stable.
I am concerned whether it is cowhide or horsehide however, as they have different reactions to different oils and solvents.

....Cotten

[Paquette]

Cotten,
I am not sure what it is that you are trying to make: what ounce leather, what temper, dyed or raw, etc. If you can give me a bit more info, I might have some ideas. You can just post here or e-mail me ---- jester@worshamcastle.com

[Tommo]

Cotton,
My cobber and I recon a lot of model H carbs and we gave up using leather a long time ago.
Leather valves are ok if you use the bike everyday and once damp with the fuel mist they will stay flat and seal so long as they don't dry out.
On bikes that are only used spasmodically the leather drys out and warps and then doesn't seal properly which leads to very rough running. This is what gives the Model H it's bad name.
We use a modern plastic in place of the leather and a lot of trial and error by us has found a spring setting that makes things perfect.
We make our own springs for the "flutter valve" as we call it and it's revised tension gives you the required range of mixture setting. The weight of the valve assembly and the spring tension is quite critical but if you want further details e-mail me direct and we can discuss it further.

Regards, Tommo

[INLINE4NUT]

Tommo how far from cambridge are you ??

[Tommo]

About 5 hours drive south. Roughly 250 miles

[JohnR]

Is this the Model H being discussed?

http://www.indianmotorbikes.com/reso.../hschebler.jpg

[AdminGuy]

Thanks Tommo. Much appreciated.

[T. Cotten]

JohnR!

So far, all of the H models across my bench have had the same airvalve (or "flutter valve".

The diagram you posted applies generall to all, from my meager experience.

Tommo's post has me all upset, as his experience obviously exceeds mine, and I already have sent too many out with any saddleleather that was handy.

Bless this forum for this valuable exchange of information! Too many vendors think such gems be sacred knowledge to covet and hide.

....Cotten

[JohnR]

Cotton,

Actually I had no idea what you were asking about" H model airvalve"? I did a Google on the subject and came up with the Indian Carburetor illustration. So I ask and apparently it was a carb design.

An early predecessor to the CV concept??

[T. Cotten]

JohnR!

"CV" means "Constant Velocity"

In my humble opinion, that is an ideal that cannot be approached short of fuel injection, although a Keihin tagged one of their designs as such. (They are very good carbs, but they are modern, and might as well be a piece of a flying saucer if tacked upon a vintage machine.)

Come to think of it, HD used them somewhere in the 80's and later, I'm told.

But that's after my time, so I shall defer to others more familiar with recent hardware.
This forum is for antique and classic motorcycles, and I won't confuse the issue.

....Cotten

[LouieMCman]

Great diagrams of the Schebler carb John, but it doesn't show the extra hole and manual valve in the body for the really high speed running. I too fabed up a piece of plastic with beveled edge in my carb and it works good on my '20 Sport model and as Tommo said, the spring tension is the critical adjustment. It took me a few trys but now the bike flys down the road at a blistering speed of 35 - 40.

[T. Cotten]

Louie,

Not all H models had the side aperture (See attachment.)

Of the few that have crossed my benches, no two have been alike, even when they were supposed to be.


....Cotten

[LouieMCman]

Thanks Cotton, I didn't know that. I learned something today now I can quite trying so hard. I've been working on an Italian bike that's been twisting my brain any way.