I've got a little head shaking going on

[Scoots]

Going down the road just the other day I took my hands off the bars to get rid of a bee that decided to check out the inside of my helmet (successful eviction without getting stung! ). Anyway, my handlebars started to do a little shake. I put my hands back on the bars - no shake. Doing a few "no hands" experiments I discovered that just the weight of one hand on the bars ceased any shaking.

At home I blocked up the engine so that if I could determine any looseness in the steering head bearings. I discovered that I do have a very small amount of play when doing the push-pull check on the bottom of the fork tubes. Not much and the movement was hard to detect. The forks glide from side to side with NO notchiness or sticking.

So, I now have to tighten up the steering head bearing a little on my '89 R100RS. Does anyone have a link to this procedure or can coach me on this?

THANKS!

[Kurt in S.A.]

Do the forks move on their own when you nudge them towards one stop or the other? If they pick up speed and bang off the stop...too loose. If the forks stay where you put them...too tight. That's they way I've been setting up my steering stem bearings. If you have fork boots, etc., this might be more difficult to do.

Kurt in S.A.

[ME 109]

Is your rear tyre flattened off? That will cause symptoms you mention. As well as a hole bunch of other things..............

[Jean]

Mess with the air pressure in the front tire before you tear into the forks.
My R75/5 shakes when the pressure is low...steadies out when it's just right.
How come? Dunno, but it works.

[Ken in Oklahoma]

The front tire can also be a culprit. I had similar symptoms on my R75/6 many years ago. Air pressure etc. didn't seem to make any difference. I replaced the front tire and the problem was gone.

Duane Ausherman, who posts here on this forum has written a LOT about this subject. The following link might prove instructive: http://w6rec.com/duane/bmw/wobbles.htm

Duane probably talks about it in the above link, but a load high and to the rear (as in a loaded top box) is the worst place to carry a load on a motorcycle, in the off chance that you're doing that. Such a load can and will cause similar symptoms. I do run a top box on my R100/7, but not with anything heavy in it. (Duane would not recommend running a top box empty either.)


Ken

[ME 109]

Got to disagree there Ken.
Two-up, fully loaded for touring, rock solid.
Year after year after year.
No Gummikah when the /7 is loaded like this.
(haven't got the sleeping bags on top of the panniers yet)
Well, there is gummikah up to about 35 mph, If one gives the bars a shove to see what happens.

At 50-80 mph she's on rails. A Kenworth on rails. Handles superbly, predictably.
Yer just don't want to have to do anything in too much of a hurry. Like stop for example.

[Scoots]

Thanks for all the replies and the links to good information - I'll explore a little further before I do anything.

When I purchased the monoshock RS it had new Metzeler Lasertecs on the front and rear. In my opinion, they track tar snakes and grooves in the road badly. I have about 4k miles on them and the rear tire is starting to flatten out a little, but I'll ride 'em out and replace them with Michelin Pilot Activs or Bridgestone BT-45's. In the meantime, I'll experiment with tire pressure - right now 34psi front and 38psi rear. Suggestions???

Prior to installing the "rubber cups" that the forks go thru in the fairing (they were MIA when I purchased the bike), I could easily swing the front tire with a finger from side to side - all smooth & no notchiness. The rubber fairing cups add a little more resistance to that test, but still smooth.

I do carry the stock 22l top case on the bike. I carry nothing heavy in it, just some essentials for work, but I've since read that a top case can change the aerodynamics and handling of a bike, even when empty. So ........

Keep those thoughts coming - I appreciate them!!!

[lrz]

You've got a mono; how's your rear shock?

[Jean]

ME109, IF you were riding alone with that tall load, how would it feel?
On the R100s with s faring, I've experimented with load arrangement and found if I pack for solo riding with some stuff close behind me, and distributed to the rear, things are pretty stable. IF I leave seat room for a non-existent passenger, weird things happen over 50 mph. (unpleasant weird things!) RSs are probably a lot more forgiving due to the aero-designed faring.
Another way to say this is I've never seen an airhead RT on the autobahn.

[ME 109]

ME109, IF you were riding alone with that tall load, how would it feel?
On the R100s with s faring, I've experimented with load arrangement and found if I pack for solo riding with some stuff close behind me, and distributed to the rear, things are pretty stable. IF I leave seat room for a non-existent passenger, weird things happen over 50 mph. (unpleasant weird things!) RSs are probably a lot more forgiving due to the aero-designed faring.
Another way to say this is I've never seen an airhead RT on the autobahn.

Gidday Jean!

You may have something in regard to the RS fairing, and then maybe not.
One up, two up, it doesn't matter.
I can be loaded like that for a solo outback trip..........and sit on the pillion seat @ 70 mph.
I believe that a snowflake seriously stabilizes the front end once sufficient speed is reached.
I have experimented many times with inducing head shakes at speeds below say 40 mph. At those lower speeds it is easy to get things loose, so to speak.
At above 50 and beyond, things become very solid.
What I have noticed is that the weight of a pillion or touring gear stabilizes the rear end because the 'weight' can't shift side to side quickly enough, effectively dampening any wobbles.

The thing I've found that most destabilizes my RS is worn tyres, particularly the rear as it flattens off. The flattening off varies from brand to brand and of course riding style. The rear tyre I found that kept its rounded profile the best, was by far The Michellin Mac 50. I could wear those Macs out without them flattening off.
The worst I found was a BT45. Flattened off well before it was worn out.
The more our tyres wear, the more effect road irregularities and road grooves etc will have in the way of handlebar wobbles.
When my RS gets two new tyres at the same time, the handlebar instability is non existent. Tested over road surfaces that I know from experience would produce wobbles with worn tyres. Unbroken white lines on the highway are classic wobble inducers. New tyres, no wobbles.

One up touring.



Two up touring.