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1969 R69S US Crank Balancer (damper)
1969 R69S US Crank Balancer (damper)
Next question would obviously be do I really need it. At my age I don't "ride like I stole it". I'm pretty easy on the old girl and don't run the RPMs much past 4000 - I have an original oil pump tach installed so this isn't a guess.
Thanks for the help,
Scott B.
Stoney Peak BMW Service
Victoria, BC. Canada
BMW Classic and Vintage Motorcycle Service and Restoration
service@stoneypeak.com
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Re: 1969 R69S US Crank Balancer (damper)
There is a rubber "ring" in the center of the damper assembly that needs replacing regularly. Been a long time since I rode a /2 with one, but as I recall, I needed to replace mine every 2-3000 miles. When they get worn, the heavy outer damper ring gets loose (it should be difficult to spin by hand when the rubber ring is new) and causes a serious out of balance situation. It WILL eventually cause damage if you don't service it. Makes a lot of rubber dust in the front cover as well. During a cross country trip I took back in the '70s on an R69S, I ran out of replacement rubber rings and couldn't find a dealer that had any at the time. I ended up just removing the damper and put another 100k miles on the bike with no issue. Still have the bike to this day. Pics below should be self explanatory but note there is an extra rubber ring shown in the pics. The proper assembly uses just one.
Hope that helps.
Chuck S
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Re: 1969 R69S US Crank Balancer (damper)
This past year or so, I was chasing a vibration and one of the first things recommended was to remove the balancer which I did. It wasn't the source of my vibration. I left the balancer off and don't plan to put it back on. As I understand it, the balancer is likely needed for situations where you are running near max RPM when the crank might flex a bit. That's not my case and never will be. So, the balancer sits on the shelf.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
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Re: 1969 R69S US Crank Balancer (damper)
tommy
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA
Re: 1969 R69S US Crank Balancer (damper)
Chuck, Mine is pretty much free wheeling on the rubber ring and there is a fair amount of rubber dust in the cover so it is well past it's best before date.
I'll order a shorter hex bolt and replacement parts so I have a working one on the shelf if I notice a difference in how smooth the bike is.
One quick question - is the part number ...203 the short one I need to replace the ...145 one?
Vibration damper hex bolt (60 Watt): 11 23 0 070 145
Armature hex bolt (60 Watt): 12 31 8 002 203
Thanks again for the help,
Scott.
Stoney Peak BMW Service
Victoria, BC. Canada
BMW Classic and Vintage Motorcycle Service and Restoration
service@stoneypeak.com
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Re: 1969 R69S US Crank Balancer (damper)
As a temporary (or permanent) fix, you can just remove the outer "balancer" ring, etc. and just reinstall the inner assembly with the long hex bolt. All should be good. (Ask me how I know... LOL!) Others can pipe in about the correct shorter hex bolt.
Chuck S
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Re: 1969 R69S US Crank Balancer (damper)
12 31 8 002 205
Interestingly enough, the very early R69S was not delivered with the vibration damper. I own a 1961, the 35th off the production line, and it never had the crank damper nor the bulged cover to accommodate the damper. Nor does it have the rear fender "R69S" emblem on the rear fender.
Unless you are going to play Rodney Roadrace with red line shifts, the damper isn't necessary, and one that the internal rubber sleeve that has disintegrated in is far worse for the engine, with that out of balance steel mass flopping around, which will hit the inside of the generator cover, gouging the inner surface up pretty badly...
This is my R69S, in original paint. you can see the gen cover without the bulge.
The pin stripes are pretty worn away on the sides of the gas tank, from years of use.
Technical Adviser, Former owner, Bench Mark Works
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Re: 1969 R69S US Crank Balancer (damper)
With the third "Atmospheric River" pounding us on the island today, I'm a little tired from being up every few hours to check for potential flooding. The ...205 was what I meant, the ...203 is the armature.
My 1961 R50S also doesn't have one. I do see it as a listed item in the MAX BMW parts fiche, but I'm not sure it would fit under the cover on that bike.
Thanks again for the help,
Scott.
Stoney Peak BMW Service
Victoria, BC. Canada
BMW Classic and Vintage Motorcycle Service and Restoration
service@stoneypeak.com
- vechorik1373
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Re: 1969 R69S US Crank Balancer (damper)
By the time I built this bike, (This is one of the last ones that I built for myself) I was sick of black BMW's, so this one is Bristol Gray..
Technical Adviser, Former owner, Bench Mark Works
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Re: 1969 R69S US Crank Balancer (damper)
Mine is still in barn find rust, but is next on the list for restoration. I was thinking black, but lately I've seen several non black R50S bikes so I may go with something else to "change things up".
Thanks for the info on the damper and the photo of your R50S. That is a stunning bike.
Scott.
Stoney Peak BMW Service
Victoria, BC. Canada
BMW Classic and Vintage Motorcycle Service and Restoration
service@stoneypeak.com