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R50/2 steering damper parts length question...

ECJ
Posts: 21
Joined: Fri Dec 15, 2017 9:50 am

R50/2 steering damper parts length question...

Post by ECJ »

Hi All-

I'm in the process of mocking up a 1965 R50/2 (it's actually a conversion project with a 1974 R75/6 engine), and had a question on part length for the steering damper adjustment knob (friction type). When the rod is placed down through the steering stem, it barely catches 2 or 3 threads of the lower friction plate, and certainly does not seem possible for it to protrude long enough to thread it through the lower plate and insert a cotter pin as is required.

The stem portion of the adjustment knob (from the underside of the cast knob) measures 9 7/32", with the cotter pin hole being about 1/8" up from the end of the threads, so it would seem to be about 1/2" shy of the required length.

I'm not aware if there were different lengths of rods from other models that this has perhaps been switched out for, so maybe that is the issue (it is a 'star' type knob, not a 'wing nut' type), since this bike was in boxes when I purchased it.

Everything is seated properly (steering head bearings, top triple, upper detent cap and slotted washer, upper friction plate, etc.), so it's a bit of an irritating conundrum, especially for a component that will probably not even be used since I'm not hauling a side car! So, before I section it and weld in a new piece to lengthen it, let me know what I'm missing......

Thanks in advance!

ECJ

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schrader7032
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Re: R50/2 steering damper parts length question...

Post by schrader7032 »

RealOEM doesn't want to display all years for the R50/2. But the "adjusting screw" as they call it for the R50 and the one for the R50/2 1967-on are different part numbers. No other information is provided. Vech also lists two different damper rods part numbers.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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wa1nca
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Re: R50/2 steering damper parts length question...

Post by wa1nca »

Yes 2 different part numbers and lengths
From Salis site
R27-R69s
https://bmwclassicmotorcycles.com/index ... -5443.html
245mm__9.645 inches

R50s-R69s with hydraulic steering damper
https://bmwclassicmotorcycles.com/index ... amper.html
246 mm__9.685 inches
Tommy
Last edited by wa1nca on Sat Feb 27, 2021 9:30 am, edited 1 time in total.
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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Re: R50/2 steering damper parts length question...

Post by schrader7032 »

Tommy...your second link should say 236mm. And the Salis site says that the first item covers the entire range of /2 all the way to the R69S. I wonder if the difference, or one of them, is that say for the R69S, it's a hydraulic damper whereas the other bikes fits a friction damper.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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Re: R50/2 steering damper parts length question...

Post by wa1nca »

Yes #16 from Salis site
https://www.bmwclassicmotorcycles.com/p ... -damper-i/
236mm for R50s__R69s with hydraulic damper with Red Dot
245 mm for r50__r69 with friction damper

Tommy
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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Re: R50/2 steering damper parts length question...

Post by schrader7032 »

To further confuse things, RealOEM shows #31412000048 for the R50 (pre 1961) and #31422000396 for the late model R50/2. Seems to be the same numbering system used by Vech.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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Re: R50/2 steering damper parts length question...

Post by wa1nca »

schrader7032 wrote:
Sat Feb 27, 2021 10:15 am
To further confuse things, RealOEM shows #31412000048 for the R50 (pre 1961) and #31422000396 for the late model R50/2. Seems to be the same numbering system used by Vech.
Ok Salis site shows 31422000396 is the damper for r50US R60US and R69US and is also 236 mm
https://bmwclassicmotorcycles.com/index ... -5444.html
Tommy
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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wa1nca
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Re: R50/2 steering damper parts length question...

Post by wa1nca »

wa1nca wrote:
Sat Feb 27, 2021 10:53 am
schrader7032 wrote:
Sat Feb 27, 2021 10:15 am
To further confuse things, RealOEM shows #31412000048 for the R50 (pre 1961) and #31422000396 for the late model R50/2. Seems to be the same numbering system used by Vech.
Ok Salis site shows 31422000396 is the damper for r50US R60US and R69US and is also 236 mm
https://bmwclassicmotorcycles.com/index ... -5444.html
Tommy
The R50/2 should be 245mm or 9.645 inches
and seems like ECJ may have one for the S or US models at 236mm which would be 9mm or .354 inches too short
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

ECJ
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Re: R50/2 steering damper parts length question...

Post by ECJ »

Gentlemen!

Thank you all. It would indeed seem that the previous owner had used an adjusting screw from either an S or US model.

The difference of 9mm/.354" seems about right. I will call Vech tomorrow and see if he has a 245mm one available (although I imagine it will be an expensive part....).

You can also see that the previous owner ran the damper set up this way, as there is rust on the treads of the lower friction plate where the adjusting screw stopped short. Kind of lucky it didn't rattle off at some point....

As always, I appreciate the collective and deep knowledge here!

ECJ

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Re: R50/2 steering damper parts length question...

Post by wa1nca »

over $200.00
I would weld in a piece to make it 245mm
Tommy
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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