Shimmy in front suspension question

"The Older Gentleman" <totallydeadmailbox.TakeThisOut@yahoo.co.uk> wrote in message
news:1i9keh7.8lu20l46ngvjN%totallydeadmailbox@yahoo.co.uk...
> Rider <sdfj.TakeThisOut@yahoo.com.hk> wrote:
>
>> "george the jones" <dadgreg.TakeThisOut@gmail.com> wrote in message
>> news:1193887712.406353.143760@22g2000hsm.googlegroups.com...
>> > 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
>> >
>> Did you loose a wheel balancing weight?
>
> That won't cause a handlebar wobble.
>
Why not?
If a wheel starts a wobble it is directly connected up to the steering

On Sun, 30 Dec 2007 08:54:18 +0000, totallydeadmailbox.RemoveThis@yahoo.co.uk (The Older
Gentleman) wrote:

>An out of balance wheel causes a hammering feeling, as if the wheel were
>not perfectly circular. *Not* a wobble.

He's applying cage thinking to bikes.

I used to do front end alignment. I had a pickup truck come in once and the
owner complained of shimmy in the steering. I doubted if it was alignment
related and when I got the truck on the rack, I was right. Someone had hammered
a 16oz semi truck balancing weight on the inside of one front wheel as a joke.

I removed the weight and his alignment was already in spec. The customer was
happy, and I made the easiest commission I ever got.

While some bikes tires are dynamically balanced, it's rare. Losing a weight in
dynamic balance (spin balance) *could* cause a shimmy, but there's a greater
than 99% chance that the wheel isn't spin-balanced anyway, so it's a moot point.

There's a much better chance that it's related to swing arm bearings or load
distribution than balance.

--
Jack