Front Fork Spacer

[Laughing Gnome]

as I was rebuilding the front forks on my '72 r75/5 I noticed this spacer under the guide support that is not listed in the parts diagram. Can someone shed some light on it?

[Duane Ausherman]

I don't know that part and don't understand where you found it. Can you take a photo with it in place? Then I will render an opinion, even if I have to make it up.

Oh, let me take a wild guess. Was the narrow part down inside the top of the spring?

[Laughing Gnome]

I don't know that part and don't understand where you found it. Can you take a photo with it in place? Then I will render an opinion, even if I have to make it up.

Oh, let me take a wild guess. Was the narrow part down inside the top of the spring?

Duane- yes the narrow portion goes on the spring side. Here it is included with the guide support.



and with the spring.

[Kurt in S.A.]

I still don't know what a "guide support" is, but.... But what these look like are self-made (very nicely I might add) spacers to help adjust the sag height of the springs. Most people just get the appropriate sized white PVC pipe, make a good square cut, and insert on top of the springs before putting the fork cap on.

Kurt in S.A.

[Laughing Gnome]

I still don't know what a "guide support" is, but.... But what these look like are self-made (very nicely I might add) spacers to help adjust the sag height of the springs. Most people just get the appropriate sized white PVC pipe, make a good square cut, and insert on top of the springs before putting the fork cap on.

Kurt in S.A.

BMW calls item #8 a Guide Support. Part number: 31421238904

http://www.maxbmwmotorcycles.com/fiche/ ... 1421238904

[Kurt in S.A.]

That's those crazy BMW engineers...it's just a cap nut. You just have an aftermarket or PO (previous owner) spring spacer.

Kurt in S.A.

[Duane Ausherman]

It was common back then to insert spacers into the fork. People were complaining about two things........ mostly.
1. Too much dive. That is the natural result of having a soft ride. Adding the spacer would pre-load the spring a bit and make it a bit harder. It would also reduce the total travel by the length of the spacer. Not a good thing.
2. A misguided attempt to reduce/eleminate the frequent wobbles.

The actual installation of the spacers required loosening the structure called "forks" was a real problem. Nobody knew (except us) that they should follow the factory specs in alignment. Even the factory didn't check alignment in assembly. I know that because I was on the assembly line watching them put every single part together.

A fork without any wobble would often get spacers added. It would then wobble and the spacers would get blamed. The spacers had nothing to do with the wobble. It was ignorance from the factory, dealers and owners that caused the wobbles.

San Jose offered several items to "improve handling" on these bikes. Even they didn't know about alignment, so often a stable bike would end up wobbling after installing the San Jose parts.

All this and more is on my website.

Don't start by using the spacers. Find out if you really need them, probably not. We rarely used them and had no problems.