Steering Wobble

I have a 84 GSX 1100EF, and when I ride no hands, I get a huge steering
wobble. Does anyone have any Ideas of what could cause this.

Langas

 

No, Both tyres are close to new.

 

Worn steering head or wheel bearings?

Leon

 

There is a usual checklist of front end health you need to check out and
then go to tire / frame alignment. What have you checked so far?

 

I would check the front wheel, then the steering head bearings, make sure
the suspension settings on the fork are correct and balanced. If all of
these are fine check the front fork for damage. I had an 88 gsx1100 that
always had a slight wobble when I would take my hands off the bar and it
turned out to be the front fork had been very slightly damaged, couldn't
tell by looking at it but the shop found the problem. Good luck.

 

A patient went to a doctor and said, "Doctor, it hurts when I hit
myself in the head with a hammer."

The doctor replied, "Well, don't hit yourself in the head with a
hammer, unless you like the pain or crave the attention. That will be
$100, please. Pay the receptionist on your way out."

Deceleration wobble is normal, given the circumstances. All motorcycles
will wobble when you take your hands off the handlebars. Some just
wobble worse than others.

Don't fret about it until you understand exactly what happens so you
can make a correct analysis without paying some dipshit mechanic in a
$tealer$hip to do work that your motorcycle doesn't actually need.

Deceleration wobble happens when your steering mechanism tries to do
what it was designed to do, but you have removed some of the
oscillation damping that the engineer expected to have in the system,
i.e., you have stopped holding onto the handlebars, so your arms aren't
stopping the oscillation.

Other modes of oscillation damping disappear over time. The elasticity
of new rubber rapidly diminishes, and deceleration wobble increase in
severity.

People will offer opinions about loose or worn steering head bearings,
but it would take about 100,000 miles for tapered roller steering head
bearings to wear out, and you can detect deceleration wobble on a
motorcycle that only has 5,000 miles on the odometer. I went through
all that steering head bearing business 30 years ago, and still had
deceleration wobbles.

A friendly old time biker named "Dirty Bob" clued me in as to what what
going on. I had the seat-of-the pants impression that steering wobble
somehow fed from the
rear tirecontact patch to the front tire contact patch and that when
the rear tire had a lot more traction than the front tire, the
motorcycle would wobble.

Dirty Bob said, "Well, the front tire contact patch needs more
traction, then, and you'll get more traction with a new tire which is
more compliant with the road surface."

So Dirty Bob sold me a new front tire and bought me a Big Mac, and I
went home and changed the front tire and went for a ride. I took my
hands off the bars and there was no deceleration wobble.

But, people will claim that your wheels are out of alignment and that
you need to take your machine to a special facility where a bull$hit
arti$t will charge you money to realign your frame to within 1 degree
or 1 millimeter of factory spec.

And, you can ride your machine out of that $hop and your Suzuki will
accelerate better because your wallet is lighter by about $100. In
5,000 miles, the deceleration wobble will be back.

I helped a friend haul his partially disassembled 1983 Suzuki GS-1100
to a famous frame and wheel shop and they put the chassis onto a
surface plate to check the steering head angle and whether the frame
was twisted and they determined there was nothing out of alignment at
all. But they still charged him $200.

He took the motorcycle out and rode it at 120 mph and it wobbled
furiously. He gave up and bought an old BMW that wouldn't wobble.
1982-83 GS-1100's were fierce wobblers because of the front and rear
tire sizes, the wheel widths, the tire compounds, the center of gravity
height and the rearward seating position of the rider.

I went through all that speed weaving and wobbling with my 1982 GS-1100
and determined that the cure was to put more weight on the front tire
contact patch by pulling the front forks up through the triple clamps
about 3/4 of an inch.

It made the steering feel a lot harder, but the wobbles and weaves
stopped.

Your GSX will probably benefit from pulling the forks up through the
triple clamps, but the parking lot steering will suffer. Engineers have
to compromise between high speed and low speed handling, but there is a
critical speed for *every* motorcycle, at which it will begin to wobble
and weave and shake and shimmy.

If you buy your tires one at a time, or you mix and match different
brands, you'll find that the critical speed at which the machine starts
to weave is reduced substantially.

I couldn't believe how low the weave/wobble/shimmy speed was when I
mounted a Bridgestone BT-020 on my FZR-1000. I didn't think the BT-020
would make a sportbike feel like some early 1980's UJM, but it sure as
hell did!

Just riding straight down a smooth flat road with my hands on the bars,
I could feel the motorcycle rocking slightly from side to side. That's
what it's supposed to do, but you're not supposed to feel the rocking
at only 60 mph.

Deceleration wobble is caused by the front tire's relative lack of
traction and ability to damp out oscillations caused by pavement
irregularities, compared to the rear tire's traction.

Under normal situations, the motorcycle is *always* trying to fall over
to the right or to the left, but the front tire contact patch, working
through the short lever arm known as "trail" manages to provide a
restoring force.

Front and rear tires are designed in sets, according to a formula that
considers the tires' profiles and diameters and the motorcycle's
wheelbase.

But the tires' profiles immediately begin to change. The rear tire
wears flat in the center, and the front tire concentrates its wear on
the sides, making the front tire more vee-shaped.

As the front tire wear to a vee, it has to work harder to provide the
restoring force, and the motorcycle falls over farther and the steering
weave becomes more pronounced.

And, the tread rubber rapidly loses its ability to dampen out small
pavement irregularities. It only takes about 4000 miles for the rubber
in a street tire to lose most of its elasticity and compliance, even
though a front tire might not *look* worn out until it has 10,000 miles
on it.

So, new tires, in matched sets are the cure for normal deceleration
wobbles, especially if you keep your hands on the bars.

 

Put the bike on the center stand.

Check the wheel bearings (try to wobble the wheels)
See if the front spins freely.

Check the swingarm bearings (again, try to wobble)

The steering head

The tires (no bulges, especially in the sidewalls)

Make sure the rear axle is correctly retained by the tensioners and
nut(s).

Try to make sure the front and rear wheel are well aligned.

Possibly you lost a wheen weight ?

 

Mine did that head shake thing (if that's what it is) since new.

The origonal tires wore out, when I replaced them and tightened the head
bearings a little and the problem went away.

But I'm pretty sure the problem was the front tire, for whatever reasons....
I think mfg tolerances maybe sucked in the stock ones...

Wouldn't be fair to hit on a particular tire because of one problem, but for
referenece....

Stock tires were Michelin MaCadams, replacements were a BT02's, which were a
freak'n huge improvement over the old ones.

P.

 

Make sure that the forks are not "tweaked" just a bit.

 

And he's talking complete shit about dampers being eliminated as well.

 

Any chance at all of the rear suspension being problematical? I swapped
my 1960 Ducati shocks for nicer, softer, ONE INCH LONGER Honda shocks
and developed an interesting steering wobble. Hint: Never try to tweak
the bars to see if you can figure out what's causing the problem. Cost
me some new parts and a square foot of skin.

--
Cheers,
Bev
+++++++++++++++++++++++++++++++++++++++++++++++++
Little Mary took her skis upon the snow to frisk.
Wasn't she a silly girl her little * ?