NEW MEMBER WITH A QUESTION

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GOLDLYON

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HELLO, MY NAME IS KEITH LYON AND I LIVE IN LAS VEGAS, NV. AND THANKS TO OMEGA MAN WHO SAW ME AT A 7-11 AND STOPPED TO INFORM ME OF THIS FORUM. A FEW MONTHS AGO I BOUGHT A USED 1987 GOLDWING INTERSTATE. THIS IS MY SECOND GOLDWING. I HAVE BASICALLY LOOKED FOR DCENT BUYS AND THEN SPENT THE TIME USING IT AS MY TRANSPORTATION WHILE TRYING TO INCREASE THE VALUE FOR FUTURE RESALE.

CAN ANYONE HELP WITH AN ANSWER TO THIS QUESTION PLEASE. WHEN I AM DRIVING AND I TAKE MY HANDS OFF THE HANDLEBARS THE FRONT WHEEL IMMEDIATELY STARTS WOBBLING AND RAPIDLY INVCREASES IN INTENSTY TO WHERE IF I DID NOT TAKE HOLD IT WOULD CERTAINLY CRASH. MY PREVIOUS GOLDWING DROVE SO STEADY WITHOUT HANDS THAT I COULD ENGABGE THE CRUISE CONTROL AND HOP ONTO THE REAR SEAT AND DRIVE AS FAR AS POSSIBLE.

ANY HELP WITH THIS QUESTION WOULD BE APPRECIATED AND I WOULD LIKE TO THANK OMEGA MAN FOR HIS INFORMATION AND EVERYONE SHOULD KNOW THAT HE IS DEFINATELY A GOOD REPRESENTATIVE TO HAVE FOR THIS FORUM.
THANK YOU, KEITH LYON [email protected]
 

Dadster

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[url=https://classicgoldwings.com/forum/viewtopic.php?p=221087#p221087:qrml7wd4 said:
Dusterdude » Sun Feb 14, 2021 4:41 pm[/url]":qrml7wd4]
Welcome and you might check out the steering stem bearings and the front wheel bearings and tire roundness

Sent from my LM-X420 using Tapatalk

Yep. Pretty much. :good:
 

joedrum

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A lot of times it's the tire ..if it's doing this the tire is bad cause it not rolling freely ..it's a ? On if it is responsible for the wobble ..but you have fork and bearings in stem and also wheel bearing that could be problem also pulling brake problem ..
..not a lot to go through I'd start.by getting wheel off the ground try to find play in something ..I'd take wheel off for new tire and also a lot of times low air cause tire to go bad over time ..my bet is new tire will do it but you must check all things out as tire is costly ..good luck
 

DaveKamp

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Hi Keith, and welcome to the gang!

The guys have made suggestions for all the MOST LIKELY causes for wobble. There's more, but they covered 'em...

But a little 'why' might help you find an elusive gremlin:

The basic geometry and physics of a motorcycle rolling in a straight line, is a balance between stability, and responsiveness. Look at the front wheel of a shopping cart when it rolls, and you'll see that the wheel always tries to point in the direction the shopping cart is going... it does this, because the wheel's axle is on a pivot, but is not centered beneath the pivot... it's offset. When the cart moves, the caster turns 'till the axle BEHIND the pivot, so the wheel's axis TRAILS the rotation.

Some shopping carts roll nice, but some have a wheel that flippy-flaps all over as you tour the Fresh Produce. it's doing this, because the wheel can't find a nice way to roll straight.

Grab a pop can, and a red plastic cup. Set 'em both on a flat table. Give the pop can a push... it'll roll straight. Do the same with your red plastic up... it turns in circles. Why? Because the diameter of the pop can is same on left AND right sides. The plastic cup, however, is smaller at the bottom, and larger at the top. In order to roll, the TOP edge needs to travel farther than the bottom. In order to roll a straight line, that plastic cup would need to be rolling JUST on it's TOP rim, not the side... because rolling on it's side would inherently pull it to right, or left.

Now look at a motorcycle from the side. Imagine that the forks come out of the frame, and went STRAIGHT DOWN... like a kid's tricycle. It'll steer, but you'll have a heckuva time balancing it (twitchy!!!) and it would NOT be safe to 'let go' of the bars, as that wheel will flop any-which-way at the slightest bump. Now reposition the wheel axle was 5" BEHIND the fork tubes. Yeah, it'd look stupid, but that's the way a shopping cart wheel is configured, right?
It would still be 'twitchy', NOT be easy to steer, or keep a motorcycle upright with that geometry, but with enough guts and strength, you could... it would want to go in whatever direction the motorcycle was travelling, but you could let go of the bars, and it would steer in the direction you're rolling... because you have TRAIL. More trail, means more of a 'desire' for the wheel to want to turn towards the bike's direction.

Tilt the forks to what looks more like a 'motorcycle'... this is called 'Rake'... and it does SEVERAL things, but mostly, it reduces the amount of steering response, for a given amount of steering input. Reason... when there is no rake (vertical), five degrees of handlebar turn equates to exactly five degrees of wheel direction change... but with 45 degrees of rake, five degrees of handlebar, only change the direction of the front tire by a FRACTION of that (I'd say 2.5 degrees, because SIN45 is 0.5, but there's other factors coming that invalidate that)

Now it gets funky. Take out your imaginary chalk, and draw a line THROUGH THE AIR... down the center of the steering tube, to a point on the ground ahead of the motorcycle. Now mark a point where the front tire contacts the GROUND. You'll readily see that the tire is contacting the ground BEHIND the steering axis. Yep, that's trail. Even when the wheel's AXLE is mounted on the FRONT of the tubes, the CONTACT point is still BEHIND.

Crazy, no?

No... it works!

Back to dixie cups... No... let's talk about flat-belt drives.

In an old machine shop, there's lineshafts spinning overhead, and big wide flat leather or canvas belts whirling around, driving all sorts of evil-looking bangy-rattley tools. If you look CLOSELY, you'll see the big sheaves that those belts ride on, are NOT flat. They're actually 'crowned'...

They're taller in the middle, than on the sides... like... two dixie cups mouth-to-mouth.

Why? Because the radius of the center, being larger than the ENDS, makes the belt WANT to run IN THE MIDDLE... it helps keep the belt centered.

Now imagine that sheave wasn't a sheave, but a tire, and the belt wasn't a belt, but a smooth stretch'a highway. The highway obviously isn't gonna move to keep the TIRE centered, but the TIRE will WANT to roll on it's HIGHEST.

Why?

Back to dixie cups...

If you have two facing mouth-to-mouth, and you roll it along, one side will tip, and the cup will hook in THAT direction (because they roll in a circle, not straight, remember?

On the motorcycle, the TRAIL means the wheel will CASTER... it will TRY to point itself in the direction it's rolling... a sudden jerk to the right, will lean the tire to the SMALL radius of the tire, which will then steer the tire to the right, but be counteracted by the tire wanting to roll on the center (Crown) of the tire.

Now, there's a dozen detailed variables that'll cause goofy oscillation, but by FAR the most common, is anything that will affect the way that tire WANTS to roll. A front tire that looks like a pop can (totally flat tread) or a pair of dixie cups (a wedge) will be problematic... a tire with a nice, constant curve from side to center, will be much less skittish... and USUALLY, either tire pressure, or a worn-out tire will be the primary culprit.

Wheel bearings, steering tube bearings, fork sliders, fork seals, or fork springs... bad swingarm bushings... or a CRACKED AXLE SHAFT can cause 'em to be problematic. A worn REAR tire can too... albeit not quite as much as a worn front.

Another thing that can make them very skittish... having too much weight too far to the rear.

Put away the dixie cups, wipe the spiked cool-aid off the table, put away your notebooks, take out your pencils and paper, its time for a quiz...
 

saganaga

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What everyone else said.

Note to check a front tire, you can put the bike on the center stand, put a car jack and a block of wood under the front of the engine, and gently raise the front tire about an inch off the ground. Spin the tire and sight it from the front.

It isn't the most ideal way to jack up the bike, but in the absence of a motorcycle jack, it should work. Still, I wouldn't place myself anywhere I could be harmed if the bike fell.
 

DaveKamp

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[url=https://classicgoldwings.com/forum/viewtopic.php?p=221186#p221186:2ii7w7o2 said:
saganaga » February 19th, 2021, 9:24 pm[/url]":2ii7w7o2]
...Still, I wouldn't place myself anywhere I could be harmed if the bike fell.

Dang... what's your secret? I do that every time I go for a ride... :moped:
 
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