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Proper horn mounting for R 50 S with tach drive

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jwonder
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Proper horn mounting for R 50 S with tach drive

Post by jwonder »

Hello all,

I am down to mounting my horn on the R 50 S and I have the original Bosch HO/FDG 6/1 horn which is quite large. There is no way it will fit in the space by the front of the motor.

Needless to say living in NY I need the horn and the first few test rides on the 50 S were harrowing at best without one!

I have also noticed that my front cover has a mark on the left side and I remember someone telling me once that they mounted the horns pointing out to the left when they ran the tach with hydraulic damper.

I guess I could get a smaller horn but originality is also important.

Any guidance is greatly appreciated!!!
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Re: Proper horn mounting for R 50 S with tach drive

Post by schrader7032 »

The picture of the R50S in this brochure doesn't suggest that the horn was mounted to the side. You have good skills on the BMW database so you might be able to find something more there.

http://beemergarage.com/documents/bmw1962.pdf
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Re: Proper horn mounting for R 50 S with tach drive

Post by vechorik1373 »

James

There was a bracket, to mount the horn on any early BMW that had the cam driven tachometer installed on the front generator cover. This bracket bolted to the two upper motor mount studs, and laid on top of the existing stock upper motor mount bracket.

I was told by the Archives the part number and was given some dimensions for it. For the life me, I cannot find the information that I had on that part. However, I did make one. based on the dimensions that I was given. This is what it looks like. I fabricated mine by taking a piece of steel box tubing, and carefully cutting the bracket out of the box tubing.
As you can see in the photo, it fit perfectly, and looks just like the real thing!
Screenshot_2021-11-29_07-05-25.png
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Re: Proper horn mounting for R 50 S with tach drive

Post by wa1nca »

Nice job
great info
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Re: Proper horn mounting for R 50 S with tach drive

Post by Daves79x »

The bracket is very cool, functional and all, but if I was going for perfect originality, I'd screw the tach drive and put the horn where it belongs. If not, you are always going to have a home-made part on the bike. But that's just me - carry on!

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Re: Proper horn mounting for R 50 S with tach drive

Post by jwonder »

Well necessity is the mother of invention.

I used my mediocre metal bending skills and some rattle can paint and came up with the following bracket. It is not bent straight as you may be able to see in the pictures. It clears the frame, tach mount, hydraulic damper and the front forks. It will clear those even when I aggressively push it and shake it.
FD4908E0-6D1A-41C1-8743-C03F17ECA24B.jpeg
Once I know it’s fine under riding conditions I might add a gusset to it to stiffen it up a bit.

Even though I made my own bracket I might still go with the official BMW bracket that Vech shows. Dave, if it has a part number from the archives I would have no problem recreating it for originality.
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Re: Proper horn mounting for R 50 S with tach drive

Post by vechorik1373 »

James,

After rooting around in my desk, I FOUND the bracket dimensions I was given from the factory drawing dated May 7, 1961.
I made a copy of it in metal as I mentioned before,
So don't let anyone tell you that this bracket is WRONG. This IS the horn bracket for machines with a gen cover mounted tachometer gearbox.:
Screenshot_2021-11-29_14-53-22.png
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Re: Proper horn mounting for R 50 S with tach drive

Post by jwonder »

I am planning on making at least one of those!!

Thanks Vech!!!
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Re: Proper horn mounting for R 50 S with tach drive

Post by 1967 R502 »

I had the same issue compounded by interference of a Hoskins Tank. The horn mounted on the side would vibrate with revs and bounce off the underside of the tank.

The Solution: use a different horn. A smaller one. There are many to choose from. Some are even Bosch, or Hella or Klaxon.

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