1934-1940 Horn

[FLFD7]

JR,

The military 640B was basically a Sport Scout with a few changes.

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The horn on the 640B mounted to the fork body ( not the handlebars) just like the Sport Scout.

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The 741 horn mounts to the frame under the gas tank. The 741 fork body is different than Sport Scout. It’s about an inch longer, and up top there is no mounts for the horn. I think the reason for that is the 741 speedometer mounts to the fork body (640B speedo in the dash), and if the horn is mounted to the fork body it would block the rider’s view of the speedo.

IMG_6146.jpeg

Its hard to get the above photo cause you’d need 3 hands but you get the idea.

I guess you could come up with some sort of clamps on the handlebars, but the center cast portion of the bars is pretty wide compared to the spacing of the studs on the horn so I don’t know how that’ll look.

[JTR249]

Well, the reason I asked is because I plan to mount the '34-'40 horn on the civilian 741 and thought I could use something like the two brackets that are curved from the 741 horn set-up. These are actually also shown in the 1940 chief parts manual.
They just seemed to be more ergonomic mated to the handlebars because the curve in them seems more shaped to the handlebar diameter, but I've never tried to fit them because everything is just parts right now in this early phase.
Then, I have recently acquired the 340 and '34 Chief parts books to see if there were other brackets that would work. I didn't know much about the J shaped brackets used on the 340-B.
They look like they are not open enough to fit around the bars. I also noticed in the parts book, there are two back shields (horn covers); one is a half and one a whole.
there seem to be more pictures in the later parts list manuals and I noticed the 1940 shows the half shield for that year. Other books, like Bogaert's, An American in Paris, shows many photos of actual military chiefs with full back covers on them.
Thank you for the photos and help.
-JR

[FLFD7]

Hey JR,

Let’s look at some of this. What you are calling the “J” bracket is, I think, the Chief horn bracket:

IMG_6157.jpeg

From Greers website.

Here they are mounted on a Chief fork…

IMG_6158.jpeg

They were used on 38 to 45 Chiefs and 38 to 42 Fours. They are meant to mount to the fork body, not around the handlebars.

Here they are compared to Sport Scout mounts…

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The four bigger holes mount to the horn body, the lower holes mount to the forks.

Here is an up to 1940 Chief setup…

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Along the studs on the back of the Indian face horn there is a rubber pad, then a metal cup with projections that fit inside the big holes on the mounting bracket, then another rubber pad and another metal cup, but this cup has clearance holes for the 10-32 threaded end of the stud but smaller then the 1/4” stud body. The back cover is then put on with acorn nuts. This essentially captures the horn bracket between the rubber pads, allowing the horn to vibrate, the horn is “floating” on those rubber pads.

The setup is the same for the Sport Scout except for the shape of the mounting brackets.

[FLFD7]

You mentioned about the two different style back covers, that has to do with the change in horn design from 1940 to 1941. On the later horn the 4 studs were replaced with a rectangular plate that has threaded holes the same spacing as the studs. On these horns the back cover was replaced with a single screw to a threaded hole in the center of the horn body…

IMG_6160.jpeg IMG_6162.jpeg

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Here it is set up for a Scout. The back wasn’t flat because it didn’t need the 4 acorn nuts, it was rounded, which looked better with the stream lined fenders (?).

Compare to the earlier horn….

IMG_6163.jpeg IMG_6164.jpeg

So I think where you are a little mixed up is you are looking at two different horn bodies and their corresponding back covers, and different brackets for the Chief and Scout.

Hope that clears some of it up.

Joe

[JTR249]

Yes, that clears things up. But I only need the parts you show above. I have all the parts for the 741 rounded back and brackets, except one of the long ones is broken.
I'm still puzzled as to how to figure out the handlebar mounting, like you said. That part will be a custom make if it is even possible.
Thanks.
-JR