What could be causing my wobbly front end?

[Colin Green]

I stripped down my very soft GS1100G forks recently then cleaned and filled them up (to manual specified height with forks fully extended) with 15W fork oil and wound the preload from lowest of the three settings to the firmest.

Since then I have noticed that (aside from a much firmer front end) the front end seems to want to get a wobble on whenever I take a hand off the bar or change up gears at high revs when winding her out.

I have checked the front end for movement and all good except a very minor notching feel in the middle. The head flops from lock to lock too easily as it bounces off the locks a little but I cant seem to tighten it up.

Has anyone out there recently dealt with similar issues?

Cheers

Colin

 

[Guest]

How's your front wheel bearings ????? Also , when you checked your steering head bearings , did you lift the front wheel off the ground and do the push pull as well as the side to side flop check ?? Cheers,Simon.

 

[Colin Green]

How's your front wheel bearings ????? Cheers,Simon.

Good question. I have recently gotten new ones as the guy who did my Warrant of Fitness check said I should have a look at them. but I only noticed this issue since doing the forks.

I suppose the answer is to install the new ones and check again?

You are a very fast mentor Mr Kuether

Edit... Yes, my pull me push you was ok.

 

[SqDancerLynn1]

Feeling a notch means the steering head bearings need replacement

 

[49er]

Colin, your steering head bearings need replacing, or you've over tightened their pre-load nut.

Also, are you sure that you have the struts mounted at equal heights in the top of the tree? It doesn't take much height difference to affect feel and handling.

Has your bike been dropped by a PO? If so, one or both of the struts may be bent.

 

[Colin Green]

Feeling a notch means the steering head bearings need replacement

Yes, but it is barely discernible and as I've only recently done the forks I'm wondering if there might be wider issues than simply the steering bearings (though they are my next part order) as for instance, the wheel bearings.. which I just checked again, along with steering head bearing movement across the range. I find it very hard to determine if there is any real movement in the wheel bearings (which I have & will replace this week)

Colin, your steering head bearings need replacing, or you've over tightened their pre-load nut.

Also, are you sure that you have the struts mounted at equal heights in the top of the tree? It doesn't take much height difference to affect feel and handling.

Has your bike been dropped by a PO? If so, one or both of the struts may be bent.

Yes well umm.. as it wont tighten any more.. ... and.... yes it has been been down hard at least twice from what I can tell... (welded cracks in stator cover, bad grazes to pipes, instruments, headlight rims, upper triple fork clamp bolt, pipes 1 x 1 side 2x other side, bent bars, bent [slightly visible missalignment] seat rails and badly racked pack rack frame with bad grazing.. that I can think of off the top of my head) ... Oh yeah! and bar misalignment with front wheel.. which I ram,ram,ram,ram,ram,ram,bang twisted straight when I did the forks :-& (it wouldn't budge despite every steering & triple tree clamp bolts & guard loosened) .. but I persevered and eventually won.. (run out of smiley quota)

But!! she stil looks purty..

 

[mriddle]

I once chased one down and found it to be several things ..

The biggest single improvement in my case was simply replacing the front tire.

 

[Colin Green]

I once chased one down and found it to be several things ..

The biggest single improvement in my case was simply replacing the front tire.

Cheers... did that a couple of 1000 km ago and still 90%, but thanks.. I tend to agree, now I've been typing it all out it kind of doesn't make sense to expect anything other than wobbles

 

[bwringer]

On most bikes, you measure fork oil level with the forks fully collapsed and the fork springs removed. This is normally 140mm from the top. Some models (the GS1100E) are 190mm.

If you measured fork oil level with the forks fully extended, then there could be a serious problem.

What fork oil level did you set and how, exactly?

 

[Colin Green]

On most bikes, you measure fork oil level with the forks fully collapsed and the fork springs removed. This is normally 140mm from the top. Some models (the GS1100E) are 190mm.

If you measured fork oil level with the forks fully extended, then there could be a serious problem.

What fork oil level did you set and how, exactly?

May bad!.. I meant fully compressed.. will have to check manual tomorrow as I can't remember, but think it was around 168 or 186 or something like that

 

[49er]

Yes, but it is barely discernible and as I've only recently done the forks I'm wondering if there might be wider issues than simply the steering bearings (though they are my next part order) as for instance, the wheel bearings.. which I just checked again, along with steering head bearing movement across the range. I find it very hard to determine if there is any real movement in the wheel bearings (which I have & will replace this week)




Yes well umm.. as it wont tighten any more.. ... and.... yes it has been been down hard at least twice from what I can tell... (welded cracks in stator cover, bad grazes to pipes, instruments, headlight rims, upper triple fork clamp bolt, pipes 1 x 1 side 2x other side, bent bars, bent [slightly visible missalignment] seat rails and badly racked pack rack frame with bad grazing.. that I can think of off the top of my head) ... Oh yeah! and bar misalignment with front wheel.. which I ram,ram,ram,ram,ram,ram,bang twisted straight when I did the forks :-& (it wouldn't budge despite every steering & triple tree clamp bolts & guard loosened) .. but I persevered and eventually won.. (run out of smiley quota)

But!! she stil looks purty..

You can hardly see any flaws in that pic. I like those arrows supporting it, but where's the kick starter?

 

[LarryA_Texas]

wobble?

wobble?

wobble can mean different things.

I had a GS1100 that would wander a bit on the road as if I was catching a very strong crosswind gust. Only it would happen with no wind. No pattern to it. I found that this one had an overtightened nut on the steering stem. Bad bearings, dry bearings or a notch in the bearings will do this, too. I'd knock the nut back a bit first just to see. Grease them to be sure. Then replace the bearings if that doesn't fix it.

If your wobble is more like a vibration then you need to look elsewhere. Wheel bearing, wheel balance or even the tire itself. Since this started after the forks were worked on, it's likely that it's related to things you changed while working there.

 

[Colin Green]

You can hardly see any flaws in that pic. I like those arrows supporting it, but where's the kick starter?

It's on the left side. You don't appear to know your bikes too well

 

[Colin Green]

wobble can mean different things.

I had a GS1100 that would wander a bit on the road as if I was catching a very strong crosswind gust. Only it would happen with no wind. No pattern to it. I found that this one had an overtightened nut on the steering stem. Bad bearings, dry bearings or a notch in the bearings will do this, too. I'd knock the nut back a bit first just to see. Grease them to be sure. Then replace the bearings if that doesn't fix it.

If your wobble is more like a vibration then you need to look elsewhere. Wheel bearing, wheel balance or even the tire itself. Since this started after the forks were worked on, it's likely that it's related to things you changed while working there.

Thanks for that. I will replace the wheel bearings this week/end and will see if that fixes it. Will also order steering bearings and do them.

 

[49er]

It's on the left side. You don't appear to know your bikes too well

Hey what a great mod to my 850. Extend the shaft through the secondary gear case and have twin kick starters. Designed especially for the ambidextrous.

 

[cantstopcrosby]

not sure if more ram ramming might be the answer, but she still might not be so straight up front

but I wanted to add this - my GS was doing the same wobble, but stopped doing that when I had occasion to change the swingarm to one with tighter bushings and/or less bent in that part, now she tracks true hands free

 

[Steve]

Several things can cause a 'wobbly' front end. Many of them have been mentioned, but I will summarize:

Loose/worn wheel bearings (front or rear wheel)
Mis-adjusted forks (could be uneven tube height, spring tension or oil level)
Mis-adjusted steering bearing (loose will tend to wobble, tight will tend to wander)
And the most surpsing source: Loose swing arm bearings/bushings

Yep, if the swing arm isn't held perfectly straight all the time, it will feel like a hinge in the middle of the bike because, ... well ... it is a hinge in the middle.

.

 

[850 Combat]

That paint job is very becomming on that bike. It really enhances the styling, in my opinion.

 

[1980GS1000E]

One time I had an RD that pulled to one side while braking. It turned out to be a loose front axle.

 

[Colin Green]

not sure if more ram ramming might be the answer, but she still might not be so straight up front

but I wanted to add this - my GS was doing the same wobble, but stopped doing that when I had occasion to change the swingarm to one with tighter bushings and/or less bent in that part, now she tracks true hands free

Cheers 'cantstopcrosby' I will definitely check out my swingarm (and need to look at upgrading my shocks)

Several things can cause a 'wobbly' front end. Many of them have been mentioned, but I will summarize:

Loose/worn wheel bearings (front or rear wheel)
Mis-adjusted forks (could be uneven tube height, spring tension or oil level)
Mis-adjusted steering bearing (loose will tend to wobble, tight will tend to wander)
And the most surpsing source: Loose swing arm bearings/bushings

Yep, if the swing arm isn't held perfectly straight all the time, it will feel like a hinge in the middle of the bike because, ... well ... it is a hinge in the middle.

.

Thanks Steve. That is Gold.. especially the wobble/wandering analysis to steering bearing tightness. I just managed to tighten the bearing a bit and that has almost eliminated the bounce back from the lock but has pronounced the notchy feel considerably (definite new bearings) it has also (i think) eliminated the wobble (have to watch for the wandering)

That paint job is very becomming on that bike. It really enhances the styling, in my opinion.

Thanks. It's beautiful.. the best factory colours for this bike fer sure

One time I had an RD that pulled to one side while braking. It turned out to be a loose front axle.

Cheers.. another one to watch for