Shimmy in front suspension question

Shimmy in front suspension question

My 1981 Kawasaki LTD 550 has a shimmy that is most pronounced at 35
MPH. I've removed the windshield and mirrors from the handlebars
without making any difference. Just keeping my hands solidly on the
grips keeps the shimmy under control but it doesn't seem safe or
normal. Any suggestions would be helpful because it doesn't feel
very
solid like I would expect.

Current mechanical status:
New tires, brakes and wheel bearings
New fork seals with oil specs and air pressure per service manual
Real wheel appears square with the frame and in the right position

Re: Shimmy in front suspension question

george the jones <dadgreg@gmail . com > wrote:

> My 1981 Kawasaki LTD 550 has a shimmy that is most pronounced at 35
> MPH. I've removed the windshield and mirrors from the handlebars
> without making any difference. Just keeping my hands solidly on the
> grips keeps the shimmy under control but it doesn't seem safe or
> normal. Any suggestions would be helpful because it doesn't feel
> very
> solid like I would expect.
>
> Current mechanical status:
> New tires, brakes and wheel bearings
> New fork seals with oil specs and air pressure per service manual
> Real wheel appears square with the frame and in the right position

It's an early 1980s Kawasaki with a dreadful chassis and riding
position. Live with it.

You could try fitting a ribbed front tyre - helps act as a crutch - and
maybe change the rear shocks. I'd also check the swinging arm bushes for
play, but really, you're never going to get a 1981 LTD Kawa to behave
properly.

Oh, and check the tyre pressures.

And if you've got any luggage bolted on the back, remove it.


--
BMW K1100LT 750SS CB400F CD250 CB125 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....

Re: Shimmy in front suspension question

The Older Gentleman wrote:
> george the jones <dadgreg@gmail . com > wrote:
>
>> My 1981 Kawasaki LTD 550 has a shimmy that is most pronounced at 35
>> MPH. I've removed the windshield and mirrors from the handlebars
>> without making any difference. Just keeping my hands solidly on the
>> grips keeps the shimmy under control but it doesn't seem safe or
>> normal. Any suggestions would be helpful because it doesn't feel
>> very
>> solid like I would expect.
>>
>> Current mechanical status:
>> New tires, brakes and wheel bearings
>> New fork seals with oil specs and air pressure per service manual
>> Real wheel appears square with the frame and in the right position
>
> It's an early 1980s Kawasaki with a dreadful chassis and riding
> position. Live with it.
>
> You could try fitting a ribbed front tyre - helps act as a crutch - and
> maybe change the rear shocks. I'd also check the swinging arm bushes for
> play, but really, you're never going to get a 1981 LTD Kawa to behave
> properly.

Bullshit. I had an '81 440 LTD, that bike was as smooth handling as
could be.

Les

Re: Shimmy in front suspension question

Project Magnet #1 <test_spamgourmet@cox . net > wrote:

> The Older Gentleman wrote:
> > george the jones <dadgreg@gmail . com > wrote:
> >
> >> My 1981 Kawasaki LTD 550 has a shimmy that is most pronounced at 35
> >> MPH. I've removed the windshield and mirrors from the handlebars
> >> without making any difference. Just keeping my hands solidly on the
> >> grips keeps the shimmy under control but it doesn't seem safe or
> >> normal. Any suggestions would be helpful because it doesn't feel
> >> very
> >> solid like I would expect.
> >>
> >> Current mechanical status:
> >> New tires, brakes and wheel bearings
> >> New fork seals with oil specs and air pressure per service manual
> >> Real wheel appears square with the frame and in the right position
> >
> > It's an early 1980s Kawasaki with a dreadful chassis and riding
> > position. Live with it.
> >
> > You could try fitting a ribbed front tyre - helps act as a crutch - and
> > maybe change the rear shocks. I'd also check the swinging arm bushes for
> > play, but really, you're never going to get a 1981 LTD Kawa to behave
> > properly.
>
> Bullshit. I had an '81 440 LTD, that bike was as smooth handling as
> could be.
>
And I throw your bullshit back at you. Light and easy to handle, yes
(and yes, I've ridden one), but not a particularly good-handling bike.

I mean, the chassis dates more or less from the early 1970s....

Your ignorance shows, I'm afraid.


--
BMW K1100LT 750SS CB400F CD250 CB125 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....

Re: Shimmy in front suspension question

The Older Gentleman wrote:
> Project Magnet #1 <test spamgourmet@cox . net > wrote:
>
>> The Older Gentleman wrote:
>>> george the jones <dadgreg@gmail . com > wrote:
>>>
>>>> My 1981 Kawasaki LTD 550 has a shimmy that is most pronounced at 35
>>>> MPH. I've removed the windshield and mirrors from the handlebars
>>>> without making any difference. Just keeping my hands solidly on the
>>>> grips keeps the shimmy under control but it doesn't seem safe or
>>>> normal. Any suggestions would be helpful because it doesn't feel
>>>> very
>>>> solid like I would expect.
>>>>
>>>> Current mechanical status:
>>>> New tires, brakes and wheel bearings
>>>> New fork seals with oil specs and air pressure per service manual
>>>> Real wheel appears square with the frame and in the right position
>>> It's an early 1980s Kawasaki with a dreadful chassis and riding
>>> position. Live with it.
>>>
>>> You could try fitting a ribbed front tyre - helps act as a crutch - and
>>> maybe change the rear shocks. I'd also check the swinging arm bushes for
>>> play, but really, you're never going to get a 1981 LTD Kawa to behave
>>> properly.
>> Bullshit. I had an '81 440 LTD, that bike was as smooth handling as
>> could be.
>>
> And I throw your bullshit back at you. Light and easy to handle, yes
> (and yes, I've ridden one), but not a particularly good-handling bike.
>
> I mean, the chassis dates more or less from the early 1970s....
>
> Your ignorance shows, I'm afraid.

The LTD's had a great, comfortable riding position, much better than the
KZ series they replaced. Handling was better too, I had both at the same
time. The LTD never gave any hint of shimmy or wobble, under any
conditions, including hitting small animals at 70+ mph.

The only thing my LTD didn't handle well was a '64 Ford Galaxy 500 at 30
mph.

I assume, since you talk bad about the LTD's, that you had a bad
experience with one or more. I'd believe it was either from wear or
other issues, not due to the design. I'd never heard anyone that had an
LTD complain about the handling until now. Everyone I knew loved theirs.

Les

Re: Shimmy in front suspension question

Project Magnet #1 wrote:

>I assume, since you talk bad about the LTD's, that you had a bad
>experience with one or more. I'd believe it was either from wear or
>other issues, not due to the design. I'd never heard anyone that had an
>LTD complain about the handling until now. Everyone I knew loved theirs.

For what? Putting around town at 35 mph? Who does that?

A rider I know got rid of his LTD because it wobbled so badly at 110 mph it
scared him.

A wide rear tire on the back with a skinny tire on the front is a stupid
choice of rubber.

If you pay any attention to what's going on in the world, you may have
noticed that skinny front tires are going out of style, except on chopper-
styled cruisers, and everybody knows that choppers are all about looks.

Nobody tries to ride a cruiser fast, they start weaving all over the place by
the time they are going 90 mph.

Japan INC didn't have anything that would compete with Harley Davidson for
rider appeal back in the late '70's, early '80's, but they could easily bolt
a 16-inch rear tire onto existing motorcycles, so that's what they did, and
they came up with some fucked-up motorcycles that American riders didn't want.


I was surprised to see a lot of LTD's in western Europe in the late '80's.
Riders probably bought them because they were so cheap.

--
Message posted via MotorcycleKB . com
* w w w .motorcyclekb . com /Uwe/Forums.aspx/tech/200711/1

Re: Shimmy in front suspension question

Albrecht via MotorcycleKB . com wrote:
> Project Magnet #1 wrote:
>
>> I assume, since you talk bad about the LTD's, that you had a bad
>> experience with one or more. I'd believe it was either from wear or
>> other issues, not due to the design. I'd never heard anyone that had an
>> LTD complain about the handling until now. Everyone I knew loved theirs.
>
> For what? Putting around town at 35 mph? Who does that?

Plenty of speeds well above the posted limits, as well as all types of
road conditions.

> A rider I know got rid of his LTD because it wobbled so badly at 110 mph it
> scared him.

Was this on a public road? If so, the rider was the problem, not the bike.

> A wide rear tire on the back with a skinny tire on the front is a stupid
> choice of rubber.

Wide? compared to what? Many bikes today have wider rear tires from the
factory than the LTD's did. 130/90/16 on the rear of the one I had.

> If you pay any attention to what's going on in the world, you may have
> noticed that skinny front tires are going out of style, except on chopper-
> styled cruisers, and everybody knows that choppers are all about looks.

The front tires on the LTD's can't be compared to the skinny fronts used
on choppers. Apples and oranges.

> Nobody tries to ride a cruiser fast, they start weaving all over the place by
> the time they are going 90 mph.

Funny, never had that happen to me. Neither did my brother on any of his
cruiser style bikes.

> Japan INC didn't have anything that would compete with Harley Davidson for
> rider appeal back in the late '70's, early '80's, but they could easily bolt
> a 16-inch rear tire onto existing motorcycles, so that's what they did, and
> they came up with some fucked-up motorcycles that American riders didn't want.

There was more different in the LTD's and the bikes they replaced. The
engine was pretty much the same, as was the wiring, even down to the
point that the earlier points would wire straight in on a newer bike
with electronic ignition. The frames were close, but not the same, with
just a 16" rear wheel. Try swapping an engine from an older KZ into a
LTD and you'll see some of the differences. The engine will swap in, but
it'll require the mounts from the LTD. Been there, done that.

> I was surprised to see a lot of LTD's in western Europe in the late '80's.
> Riders probably bought them because they were so cheap.

I'm surprised to see so many ignorant opinions made from some rider
making the stupid decision to ride too fast on public roads, but
opinions are cheap.

Les

Re: Shimmy in front suspension question

Project Magnet #1 <test_spamgourmet@cox . net > wrote:

> Wide? compared to what? Many bikes today have wider rear tires from the
> factory than the LTD's did. 130/90/16 on the rear of the one I had.

And, dimwit, they tend to have fatter front ones as well.

--
BMW K1100LT 750SS CB400F CD250 CB125 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....

Re: Shimmy in front suspension question

The Older Gentleman wrote:
> Project Magnet #1 <test spamgourmet@cox . net > wrote:
>
>> Wide? compared to what? Many bikes today have wider rear tires from the
>> factory than the LTD's did. 130/90/16 on the rear of the one I had.
>
> And, dimwit, they tend to have fatter front ones as well.

Many sport bikes have rear tires much wider than the front. Must be a
design flaw.

Fuckwit, I'm done with you.

Re: Shimmy in front suspension question

On 2 Nov, 13:19, Project Magnet #1 <test_spamgour...@cox . net > wrote:
> The Older Gentleman wrote:
> > Project Magnet #1 <test_spamgour...@cox . net > wrote:
>
> >> Wide? compared to what? Many bikes today have wider rear tires from the
> >> factory than the LTD's did. 130/90/16 on the rear of the one I had.
>
> > And, dimwit, they tend to have fatter front ones as well.
>
> Many sport bikes have rear tires much wider than the front. Must be a
> design flaw.
>
> Fuckwit, I'm done with you.

Try looking for the flaw in your reasoning. Modern sports bikes have
front and rear tyre sizes *way* more carefully matched than did bikes
of yore. Now, with the old LTD bikes, they increased the width of the
rear tyres *without* doing anything about the front ones.

Do I hear the sound of a penny dropping?

The old early 1980s 440 LTD was a nice bike. Lovely soft torquey
engine, decent comfort, excellent fuel economy, superb belt drive (on
UK models - dunno if the US got the belt drive ones). Kight and easy
to handle. But a good-handling bike? No, not really.

Re: Shimmy in front suspension question

Project Magnet #1 wrote:

>Many sport bikes have rear tires much wider than the front. Must be a
>design flaw.

Powerful sportbikes have large rear tires which can take the heat of
providing grip while travelling at very high speeds around race tracks. It's
not a styling exercise.

The manufacturers first started running into problems with tread block squirm
and heat buildup in the early 1970's, when motorcycles started going 150 mph
continuously around the high-banked tri-oval at Daytona.

The used the whole NASCAR tri-oval to qualify, and they used part of the tri-
oval and the infield during the race. Tires were chunking at 150 mph, so
tires with shallower treads were developed and they were wider.

Nowadays, AMA superbikes are developing about 225 rear wheel horsepower and
even the widest tires cannot handle the heat buildup as they spin at 180 mph.
The AMA had to change the 200 mile race to the 600cc Formula Extreme class to
avoid killing somebody.

The early 1980's saw Honda and Kawasaki change from 19-inch front tires on
sportbikes to 16-inch front tires for quick turn in. during vigorous
cornering.

Again, this was NOT a styling exercise.

The bikes with 16-inch front tires were too twitchy for most racers,so 17-
inch wheels gradually became the standard.

And the width of a 17-inch front tire at abour 110 or 120 millimeters is
based upon the tire's ability to handle the braking loads. If the
manufacturers could get away with a smaller front tire and still have the
needed braking, they would use a smaller front.

However, the large rear/small front tire combo seen on LTD's and L-models of
the early 1980's was mere styling.

--
Message posted via MotorcycleKB . com
* w w w .motorcyclekb . com /Uwe/Forums.aspx/tech/200711/1

Re: Shimmy in front suspension question

Albrecht wrote:

>Powerful sportbikes have large rear tires which can take the heat of
>providing grip while travelling at very high speeds around race tracks. It's
>not a styling exercise.

Just in case you still don't understand why a large rear tire works with a
very small front tire on a modern sportbike, it has to do with weight
distribution and steering geometry.

The modern sportbike carries its weight further forward than the older
standards and L-models and has less rake by several degrees and an inch or so
less trail.

Back in the early 1960's, Americans were just beginning to see Japanese
production road racers over here. I couldn't get one, I had to build my own
from spares.

* tbn0.google . com /images?q=tbn:D0Cfnl2wzu0CgM: * w w w .realclassic.co.uk/bikepix/yam07071302.jpg


The cheap natural rubber rear tires had so little traction, the rider had to
sit over the rear wheel to get the tire to hook up at all. There was very
little weight on the front tire and the motorcycle had brakes that were
almost useless.

The racers would drag race each other from corner to corner, adjust their
speed and pray that their tires would grip well enough to make the corner.
Then they would drag race to the next corner.

As larger and more powerful motorcycles were developed, Avon and Dunlop began
producing synthetic rubber tires made of high-hysteresis "cling rubber" which
gripped better and damped out small suspension motions due to pavement
irregularities better.

Japanese tires gained a reputation of being "rim protectors" and the first
thing racers would do is replace them with Dunlops or Avons or Pirellis,
anything but Inoues and Yokohamas was a good tire.

Japanese motorcycles also had silly friction dampers to reduce steering head
shake. They didn't work worth a shit and most riders probably threw them away.


The British came to Daytona with 650 twins and 750 triples and tried to go
fast, but they were still using old steering geometry and their weight was
carried too far back.

Triumph came out with a Daytona geometry of 32 degrees rake and maybe
4.5 inches of trail, but the motorcycles would speed weave badly, so they
limited steering angle to 15 degrees in either direction.

The Kawasaki factory team used 6 inches of trail on their wobbly KZ1000
racers of the early 1980's, but Yamaha was getting a handle on what geometry
they needed to make their TZ700 racers work.

They were using 23 to 25 degrees of rake and about 3.25 to 3.5 inches of
trail.

The most radically de-raked sportbike I have ever read about is a Buell, with
only 21 degrees of rake.

--
Message posted via MotorcycleKB . com
* w w w .motorcyclekb . com /Uwe/Forums.aspx/tech/200711/1

Re: Shimmy in front suspension question

On 2 Nov, 16:45, "Albrecht via MotorcycleKB . com " <u33665@uwe> wrote:
> Albrecht wrote:

> The British came to Daytona with 650 twins and 750 triples and tried to go
> fast, but they were still using old steering geometry and their weight was
> carried too far back.
>

They were such crap that they won Daytona in 1971.....

Re: Shimmy in front suspension question

Project Magnet #1 wrote:

>> A rider I know got rid of his LTD because it wobbled so badly at 110 mph it
>> scared him.
>
>Was this on a public road? If so, the rider was the problem, not the bike.

As a matter of fact, it happened on the fastest roadracing circuit in the
western USA, where good handling smaller machines with properly matched front
and rear tires had no problems going 110 mph. Bigger motorcycles go 140
through there.

And my friend was a licensed roadracer from the 1960's, with experience on GP
motorcycles you've never heard of. He got the LTD abortion cheap, so he
decided to get back into racing on a budget. But the thing handled for crap.

>Wide? compared to what? Many bikes today have wider rear tires from the
>factory than the LTD's did. 130/90/16 on the rear of the one I had.

Some idiot niggahs are putting 300mm wide rear tires on sportbikes nowadays,
just for looks.

>The front tires on the LTD's can't be compared to the skinny fronts used
>on choppers. Apples and oranges.

Bullshit. Width is relative, not absolute. A chopper might have a 3.00x21
tire on the front, a cruiser might have a 3.50 or 4.00x19. The skinnier the
front tire, or the more it's mismatched with the front tire, the worse the
motorcycle will handle and it doesn't matter *what* you do with the steering
head bearings or the tire pressure or whatever, the skinny front tire cannot
cope with the huge rear tire.

>Funny, never had that happen to me. Neither did my brother on any of his
>cruiser style bikes.

"Absence of evidence is not evidence of absence." Claiming that your lack of
experience disproves somebody else's experience makes you sound stupid or
Ashkenazi.

>There was more different in the LTD's and the bikes they replaced. The
>engine was pretty much the same, as was the wiring, even down to the
>point that the earlier points would wire straight in on a newer bike
>with electronic ignition. The frames were close, but not the same, with
>just a 16" rear wheel. Try swapping an engine from an older KZ into a
>LTD and you'll see some of the differences. The engine will swap in, but
>it'll require the mounts from the LTD. Been there, done that.

Who would even *want* to do something like that with a mass produced pile of
crap like a 1980's UJM, except for somebody who is dead broke and has a lot
of free motorcycles?

>I'm surprised to see so many ignorant opinions made from some rider
>making the stupid decision to ride too fast on public roads, but
>opinions are cheap.

I consider the source when I read Usenet ravings.

--
Message posted via MotorcycleKB . com
* w w w .motorcyclekb . com /Uwe/Forums.aspx/tech/200711/1

Re: Shimmy in front suspension question

Albrecht via MotorcycleKB . com wrote:

> I consider the source when I read Usenet ravings.

So do I. Both you and the other idiot base your opinion on the
experience of someone else that may have had a bike that was worn out.
In good shape, the bikes handled great.

Les