Fork oil volume

["Donald Walter"]

I came across an old BMW Tech Bulletin that specified a change in fork oil volume compared to original spec. Now says for Initial Fill 250ml (was 280) and for Oil Change 235ml (was 250). Change apparently made in response to harsh ride comments from riders/dealers. I'd be interested in community feedback on this volume issue since I'm getting ready to change the fork oil in my new-to-me '76.
Further it seems the original 7.5w spec fork oil is no longer available and 10w is now recommended.

["Robert Fleischer dba Fleischer's Service"]

Your figures are correct. That is, drain and refill is to be 235 cc (265 is obsolete); and, for overhaul (that means dry to start the refilling), 25o, as 280 is obsolete.
But, be advised that BMW was installing a red oil back then, and its viscosity was not specified in the usual manner you may be used-to now-a-days. Back then, the actual viscosity was closer to 4 SAE, and in some parts of the spec, one could say it was 7.5. Yeah, confusing.
What is not confusing is the oil itself. Here in the USA, the oil being used, and for refills, was military hydraulic fluid, Mil 5606-. It is widely available.
Use of a 10 weight fork or suspension fluid would work fine.
For an article: https://bmwmotorcycletech.info/front-fo ... mounts.htm

Snowbum

["Todd Trumbore"]

Donald,

You can make your own 7.5w fork oil by mixing equal parts 10w with 5w fork oil. Just remember to relabel the container 7.5w. It’s that simple.



Todd Trumbore







I came across an old BMW Tech Bulletin that specified a change in fork oil volume compared to original spec. Now says for Initial Fill 250ml (was 280) and for Oil Change 235ml (was 250). Change apparently made in response to harsh ride comments from riders/dealers. I'd be interested in community feedback on this volume issue since I'm getting ready to change the fork oil in my new-to-me '76.
Further it seems the original 7.5w spec fork oil is no longer available and 10w is now recommended.





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["Dennis Grossman"]

I have a 74 R90/6 in addition to my 75 R90S. The start button is only
occasionally engaging the starter, and it is becoming worse. All battery
and ground connections are clean, and battery is charged. Panel lights come
on bright, and it kicks over with full power when it does connect.
I am looking for some guidance regarding where to look next.
Thanks,
Denny

>

["Robert Fleischer dba Fleischer's Service"]

The most likely problems are the start button or the starting relay. If you hear a faint click when operating the start button, but the starter does not make a loud click and start rotating, then the start relay is likely making intermittent contact. Usually can be fixed by opening and cleaning the contacts.
A voltmeter or test lamp will be a fast way to trace down the problem.
If you want the long version of all the possible various problems:
https://bmwmotorcycletech.info/startingprobs.htmm


The starter circuit (except for the /5) is very simple. That article tells all.

Snowbum

["Dennis Grossman"]

Thanks for the quick response Robert. I will read through this as well as
clean the relay contracts. I am maybe hearing a very faint click when I hit
the starter button.
Denny

On Mon, Apr 19, 2021, 4:54 PM Robert Fleischer dba Fleischer's Service via
groups.io <snowbum=bmwmotorcycletech.info@groups.io> wrote:

> The most likely problems are the start button or the starting relay. If
> you hear a faint click when operating the start button, but the starter
> does not make a loud click and start rotating, then the start relay is
> likely making intermittent contact. Usually can be fixed by opening and
> cleaning the contacts.
> A voltmeter or test lamp will be a fast way to trace down the problem.
> If you want the long version of all the possible various problems:
> https://bmwmotorcycletech.info/startingprobs.htmm
>
>
>
>
>
> The starter circuit (except for the /5) is very simple. That article
> tells all.
>
>
>
> Snowbum
>
>
>
> *From:* R90SWORLDNET@groups.io <R90SWORLDNET@groups.io> *On Behalf Of *Dennis
> Grossman
> *Sent:* Monday, April 19, 2021 4:44 PM
> *To:* R90SWORLDNET@groups.io
> *Subject:* [R90SWORLDNET] R90/6 Starting problem
>
>
>
> I have a 74 R90/6 in addition to my 75 R90S. The start button is only
> occasionally engaging the starter, and it is becoming worse. All battery
> and ground connections are clean, and battery is charged. Panel lights come
> on bright, and it kicks over with full power when it does connect.
>
> I am looking for some guidance regarding where to look next.
>
> Thanks,
>
> Denny
>
>
> --
>
> Robert (Snowbum) Fleischer, Carson City, NV, USA
>
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>

["Robert Fleischer dba Fleischer's Service"]

A test light or voltmeter at the starter relay output (either of the two terminals marked 87) will be one easy way to check the relay output…must be ~battery voltage when the push button is pressed….every time. IF OK, then check the solenoid terminals appropriately under the starter cover area.
B