R100RS Bars

[Duane Ausherman]

Irz, most adjusting of the front end sag includes a change in some aspect of the springs. This means removing the two top nuts that hold it on the top end. It is very easy to change the alignment during that process.

It is easy and common to start out with a stable front end, change something and end up with a wobble. The wobble may well be due to misalignment and not the change that was made. Back in the day it was common for people to install some of that performance equipment and end up with a wobble. Then they blamed it on the product, not their own incorrect procedure. Lots of "maybe good stuff" got trashed for the wrong reason. Often the small manufacturers had no clue about alignment and no warnings in the installation directions. Even if they understood it, the process of alignment intimidated so many that they didn't want to include it in the instructions and discourage a purchase.

This info isn't just for you, but another general warning about this very serious safety issue. I would check stiction before I started, make the changes one side at a time and then check stiction again to make sure it didn't go south.

Even using a torque arm to remove pressure on the alignment and only doing one side of the fork at a time, one still runs a considerable risk of misalignment of the forks and getting stiction. That can result is a stability problem and even a serious high speed wobble.

When this comes up at a tech session, usually we go around and test stiction on every BMW that we can get permission. We have never found less than 25% of the bikes with very serious stiction problems. In nearly every case the owner had no clue. Most don't even know what we are talking about. Many don't care either.

Anyone who has ever had a high speed wobble will tell you that it is something to be concerned about. I have never heard anyone tell me that it wasn't a concern because it was easy to get out of it. Some riders have low risk wobbles that don't go out of control and the riders just put up with it.

A few years ago I was on my way to Texas and going across Arizona a group of HD riders passed me. At the rear of the group of 10-12 bikes was a woman on her HD. It had a fairly serious weave. I followed for quite a distance and it never went away. The fact that she was in the rear told me that they all know about it and didn't want to ride behind her and risk crashing into her as she crashed. Nice people.

It could have been one of the HD from the years of serious wobbles around the turn of the century. At least one big class action lawsuit was opened. I don't know how it came out.

[lrz]

Just walked in the door from a "test" ride/ customer meeting.

As far as the sag, what I was doing was correcting a set of Progressive brand springs I installed, against popular opinion, 2 yrs ago. I really like them in the /7, not so keen in the rs. What I did, & iirc you actually mentioned this somewhere at some point, was to remove the preload spacers because in the interim I also fitted new rear shocks . Better actually. I did not test stiction this time but there actually was none upon initial installation.

I have to say, I finally confirmed that the low speed (@30mph) wobble I've experienced only occurs on my road; the way it was paved left an almost rain groove surface some combo of dirt, asphalt & tar .

So as not to hijack the thread entirely, Bob, if you are still here, I spent maybe an hour last night adjusting bars,perches and brake line until max upward angle as dictated by the fairing was achieved. Pretty close to the K bars as I recall though w/out the back aspect.

[Duane Ausherman]

Irz, I just came in from doing some clean up in the yard. Sounds like all good news to me. Rain grooves do not cause a wobble, but can only induce one on an already unstable front end.

Most don't like riding on rain grooves and I don't either, but they aren't dangerous. I have several times demonstrated that a stable bike can be ridden hands off the bars on rain grooves. The bike will "walk around" a lot, but not go into a wobble.

On gravel and sand roads a bike with a low speed wobble will be far more stable due to the fact that there isn't enough traction to sustain a wobble. A wobble requires feedback to sustain itself. Remove the feedback and a wobble is gone.

If a wobbler is put on the center stand and the wheel spum up, it won't wobble. There is no feedback from traction, as there is no traction. This assumes that the wheel is round and balanced.