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hooverbj
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VBMWMO #9255
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After being convinced that my 66 R50/2's speedometer either didn't have a light or it wasn't working. I finally pulled my speedo out to see if it even had a light, and sure enough, one little bulb. I wiggled it a few times just to make sure it had contact, but nothing. I hooked up a testing light to the base of the bulb connector and grounded it to my cylinder head and it lite up showing that there is power there. I am now assuming that there is a bad ground. Can anyone tell me where I should look for a ground on the speedometer?

schrader7032
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VBMWMO #7032
San Antonio, TX
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I would have thought that the

I would have thought that the speedo body itself would be ground. Can you measure the resistance between the speedo body and the engine frame or battery negative?

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
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Bad ground to speedo

Yes you do have a bad ground to the speedometer housing
The speedometer gasket and the 2 insulated screws and washers that hold the headlight shell to the ears do not provide a good ground

The fix is easy
Just add a ground wire on the speedometer shell to the ground terminal on the switch board
(The large brown wire connected to the switch board terminal #31)

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

Twocams
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I lost the ground on terminal

I lost the ground on terminal #31 and tinned a piece of wire Unscrewed the speedometer nut. Wrapped the wire around the speedo and tightened up the speedo nut. Hooked the other end to #31. had a good ground until I get time to fix properly. And thats all I got

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

wa1nca
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VBMWMO #8374
Ashfield Ma.
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Speedo housing ground

Two cams
Yes I would also try to fix correctly someday
Thanks

The ground path from the speedometer is via the speedometer cable to the housing on the transmisson

I now think that the some of the new aftermarket speedo cables are not terminated ground wise from one end to the other

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

wa1nca
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VBMWMO #8374
Ashfield Ma.
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Ground for speedometer housing

The ground path for the speedometer is completed by the speedometer cable for the night light in the speedometer

I tested 5 cables
3 had continuity from one end to the other
The last 2 I bought had no continuity from one end to the other and I also had to add a separate ground to make the light work

I never would have guessed the the cable also provides the ground for the speedometer

The only solution is to add a separate ground
Small wire from # 31 to speedo housing

I bought mine from a well know source here in the USA

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

Twocams
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I bought both my cables from

I bought both my cables from Hansans BMW in Medford, Oregon. They had to order them 4-5 days free shipping. 69 R69S/ 92 R100RT.
The thing that had a good ground was the U bracket that held the speedo in. Had my test lite hooked to that for all my testing inside the lite bucket.

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
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speedo cable

Was your cable a original bmw part or a aftermarket

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

Twocams
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Now Tommy why do you have ask

Now Tommy why do you have ask things like that? I gave them the BMW part # (10 digit? ) They looked in their puter and said OK on order.
Be in on next order 4-5 days.
Now is BMW really making this stuff....I dont think so.

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

wa1nca
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Ashfield Ma.
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speedo cable

This now seems like a real safety issue for night driving
If the driver cant see how fast they are going he may be going to fast for the road or worse yet could get a speeding ticket for going too fast

I have made up a grounding kit and will sell for 19.95
2 for 36.00

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

stagewex
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VBMWMO #8810
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Who is riding their 50/2's or

Who is riding their 50/2's or 60/2's so fast that they are going to get a ticket?
Smile

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mike wex/stagewex
1969 BMW r60/2, US Model, 1995 BMW K75, 2006 Yamaha TW200, 2007 Ural Patrol

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
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Speeding

That is true
But it could happen

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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I think it was attributed to

I think it was attributed to vehicles with Lucas electrics, but "A gentleman does not motor around after dark." Big Grin

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

hooverbj
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Joined: 04/01/2017
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LED Substitute

Does any one know if there is an LED substitute for this little light? It would be easy if the light had both + and - connectors.

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