Got A Wobble . . .

[cozee]

'83 GS1100GL Between 40-50 mph, I have a wobble. This isn't an issue non-issue outside this mph range, just in it. With with both hands on the bars it isn't really an issue. One hand on the bars you can notice it. With both hands off the bars (but still hovering over the grips, ready just in case!!!) and the wobble has the potential to become so severe that it could cause to bike to go down. I can find no apparent damage or issues with the front end (tire, rim, forks, etc). All bearings (front wheel and neck) seem fine. Any ideas on what to check?

[NetBSD]

is it a spoked wheel? if so it might need to be adjusted, also is the wheel balanced? those 2 will cause what you have going on. when my and my boss restored his 73 triumph 750 the front wheel was spoked and out of wack, anywhere above 60mph it would wobble like a SOB

[chef1366]

How are the tires?

[bonanzadave]

I had a bent rim and a buldge in my tire with that same wobble. Scary ! New (used) wheel, Rotors, New tire...........same wobble. It was the steering head bearings.

[SqDancerLynn1]

Check the steering stem bearing preload, maybe just tighten 1/16 of a turn doesn't take much. Raise the front wheel off the ground, the bars should move freely from side to side

[Tom MLC]

Steering head bearings. Most definately.

[cozee]

Thanks all!

I give a closer inspection and a little tweek tomorrow!

[Zook]

This is most definitely steering head bearings that are too loose. The bars should have just a bit of resistance....I'll repeat, just a bit of resistance.
It's a decelleration wobble, right?
Grabbing the front wheel and pulling it back and forth will not make the problem show up.
To check, place the bike on the c-stand and raise the F wheel. With the bars full left and one hand lightly holding the bars, drop the F wheel onto the ground. If the bars "bounce" more than once, the bearings are loose.

Don't forget to loosen the lower clamp pinch bolts before adjusting the bearings or you'll bind the forks.

Many people think it's the tires causing the problems and change the tires...and the problem gets worse, unless the tire is specifically designed for that bike, such as the OEM Dunlops for the Kaw Concours 1000.
They were designed to mask the problem and do a good job. Put on new tires of another type, and the wobble shows up. Tighten the bearings and all is well.
That is what happens when you put bearings on a 700# bike that are designed for one that weighs around 500#.

[ned37]

another issue that a lot of people overlook is a bike with a rack or top box on a rack with some weight on it. it will cause the same symptoms even if all the other adjustments and alignments are good.

[Zook]

Also check swingarm bearing adjustment and rear tire pressure. Loose bearings will show up at the front rather than the rear.

[PAULYBOY]

another issue that a lot of people overlook is a bike with a rack or top box on a rack with some weight on it. it will cause the same symptoms even if all the other adjustments and alignments are good.

So, would my bike, with my 450 lb. fat @$$ on it, have those symptoms?

[Zook]

It COULD, but I will bet it's from adjustments. The reson a rack, etc causes the problem is due to weight being too far to the rear. Since it's behind the R tire it acts as a lever, trying to lift the front.

[paco13]

I began having the same exact problem abought a month ago on my 750 @ 40MPH decel.
Haven't been able to get it on my lift to recheck the head bearings, its been occupied with a disabled Harley awaiting parts, but thats another story.
I had already changed the front rim,tire,wheel bearings(front and rear) with no effect. The head bearings were checked not to long before this started but will recheck.

Now you've got me thinking. I installed a rear rack with sissy bar (and milk crate) Yup, about a month ago, Hmmmmm?

Also, I had a decel wobble on a mid 90's Katana a while back that was cured with new fork springs and slide bushings. That was my next suspicion since the GS has the sacked out stockers in it.

When I get to it I will post what I find.

[Steve]

All good points above, but another thing to look for is, again, in the steering bearings. The bearings on my bike are plenty tight when the wheel is not straight ahead. When the wheel is straight ahead, there is a 'notch' in the bearings, making it feel like a detent meant to keep you straight ahead. This is not right. The forks should turn smoothly from one extreme to the other, with no detent in the middle. If I were to tighten my steering head while the forks are in that detent, the bearings would probably be too tight to ever get out of it. The only cure, in my case, is replacement of the bearings. I have the new bearings, I am just waiting for the riding season to slow down, and I am keeping at least one hand on the bars in the meantime.

.

[Zook]

You can also turn the bearing race 90 degrees as a cheap temporary "fix".
But if you're going to go that far you may as well replace it.

The key thing with steering head bearings is they need some preload on them. They shouldn't be loose enough where they will flop to full lock with just a tap.
Many call for 5-7 lbs of force to get them to move. The "feel" method is to tighten the bearings just enough where you can start to feel some resistance when turning the bars.
You have them too tight when the bike tends to wander and you are always making steering corrections in a straight line.