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-   -   Wobbly handlebar on motorways ( https://www.xt660.com/showthread.php?t=16346)

zakidos 09-03-11 10:58
Wobbly handlebar on motorways
 
Hey T�n�r� addicts!

In the last couple of weeks I noticed that my handlebar gets unsteady/starts wobblying around on motorways (120km/h). I'm not sure if it has something to do with vibrations in general (but it wasn't always so on motorways!) or maybe my wheels are out of balance or I get a bend in the rim somewhere or the tyres... I don't know... Or is it simply time to change the headset bearing? I've got 22000km on my clock...

Any ideas?

Thanks! Much appreciated.

Cheers, Mike

uberthumper 09-03-11 11:22
What sort of tyres have you got on? That sort of wobble isn't unusual with knobblies, and it can come and go depending on the amount of tread left on the tyre. Changing the pressures a few psi up or down can cure it.

Or it could be any of the other reasons. Pretty easy to check the wheel runout and headstock bearings if you can get the front wheel off the floor.

Stumpy 09-03-11 11:28
I had this when I had a Tenere. It was loose spokes on the front wheel.

zakidos 09-03-11 13:10
I do have knobblies on (TKC80) which don't have much tread left. And I'll check the spokes this afternoon!

How can I check the headstock bearings by myself?

uberthumper 09-03-11 13:32
Support the front wheel off the floor so the entire front end is free (ie using something like a centrestand plus a jack under the sump, not a front paddock stand of any sort.

Move the steering through its full range of travel and see if it's smooth - when headstock bearings wear they typically develop a 'notch' around the straight ahead position, which you should be able to feel.

Grab hold of the forks at the bottom and waggle them around to see if there is any play at the headstock.

If there's play, but the bearings don't feel notchy, you *might* be able to get away with just tightening them up a bit (take off the top yoke and tighten the locknut underneath). If they're notchy they'll definitely need replacing.

I'd be surprised if they've gone, but you never know. The Japanese manufacturers do seem to have a reputation for assembling them without enough grease in.

Pleiades 09-03-11 14:13
Quote:
Originally Posted by zakidos (Post 150989)
I do have knobblies on (TKC80) which don't have much tread left.
It'll be the tyres. TKCs do this, particularly when worn.

Gas_Up_Lets_Go 09-03-11 14:24
Quote:
Originally Posted by zakidos (Post 150989)
I do have knobblies on (TKC80) which don't have much tread left.
I wouldn't like to say what your problem is, but I've had lots of different results from TKC's depending on how much tread is left. Sometimes they can wobble at 30mph, other times at 70+

stumpydave 09-03-11 20:17
I had this with my swiss army tyres when new. Was so convinced something was wrong i took the tyre back off and refitted it. Now 1000 miles later theyre sweet as a nut. At least i know what to expect next time.

zakidos 10-03-11 10:52
Quote:
Originally Posted by uberthumper (Post 150993)
Support the front wheel off the floor so the entire front end is free (ie using something like a centrestand plus a jack under the sump, not a front paddock stand of any sort.

Move the steering through its full range of travel and see if it's smooth - when headstock bearings wear they typically develop a 'notch' around the straight ahead position, which you should be able to feel.

Grab hold of the forks at the bottom and waggle them around to see if there is any play at the headstock.

If there's play, but the bearings don't feel notchy, you *might* be able to get away with just tightening them up a bit (take off the top yoke and tighten the locknut underneath). If they're notchy they'll definitely need replacing.

I'd be surprised if they've gone, but you never know. The Japanese manufacturers do seem to have a reputation for assembling them without enough grease in.
Thank you uberthumper for the great explanation. I'll check that today. But I'm not so worried anymore. I simply blame it on my TKCs ;-)

Denny 10-03-11 11:22
Top case, brush guards, tyre pressure/balance, bearings can all play a part in speed wobbles on the XTX/R version.

Peatbog 11-03-11 00:53
I had the same thing when i had those same tyres on- I wound up the rear preload two clicks and it went away :)

zakidos 11-03-11 20:41
Quote:
Originally Posted by Peatbog (Post 151108)
I had the same thing when i had those same tyres on- I wound up the rear preload two clicks and it went away :)
Got to try that as well ;-)

Thanks for the hint!

GBX 22-03-11 09:29
Also the tenere is a dual sport so it is not fitted with any steering dampers like sports bikes to stop these "speed wobbles". I have experienced the wobbles with the standard tyres when driving at high speeds on the tenere also and I�m confident its not down to any damage or 'issue' with the bike.

zakidos 22-03-11 11:55
Quote:
Originally Posted by GBX (Post 151826)
Also the tenere is a dual sport so it is not fitted with any steering dampers like sports bikes to stop these "speed wobbles". I have experienced the wobbles with the standard tyres when driving at high speeds on the tenere also and I�m confident its not down to any damage or 'issue' with the bike.
Waht is 'highspeed' for you? I'm talking about regular motorway speed, 120kmh (75mph). I hope it's from the tkc's, because this is something new I haven't experienced before.

GBX 22-03-11 15:50
Quote:
Originally Posted by zakidos (Post 151842)
Waht is 'highspeed' for you? I'm talking about regular motorway speed, 120kmh (75mph). I hope it's from the tkc's, because this is something new I haven't experienced before.
I'm pretty sure it will be the tyres but theres no harm in being safer than sorry, consider what the guys here in previous posts told you to check over firstly, but i have had this wobble at 70mph+ on various dual sports / supermotos on motorways in the past, and i guess its expected pushing dual sports that speed without dampers, ultimately it is when you accelerate and the front wheel is not making solid contact with the road if i am correct.

zakidos 22-03-11 17:18
Quote:
Originally Posted by GBX (Post 151859)
I'm pretty sure it will be the tyres but theres no harm in being safer than sorry, consider what the guys here in previous posts told you to check over firstly, but i have had this wobble at 70mph+ on various dual sports / supermotos on motorways in the past, and i guess its expected pushing dual sports that speed without dampers, ultimately it is when you accelerate and the front wheel is not making solid contact with the road if i am correct.
Ok. But how do KTM or BMW handle this issue? I know for sure that with the big 1200GS you don't have this wobbles at 70mph (maybe at a later time). And the KTM 990 Adv shouldn't wobble either. Ok ok, they are a bit in a different league though ;-)

GBX 22-03-11 17:47
Quote:
Originally Posted by zakidos (Post 151866)
Ok. But how do KTM or BMW handle this issue? I know for sure that with the big 1200GS you don't have this wobbles at 70mph (maybe at a later time). And the KTM 990 Adv shouldn't wobble either. Ok ok, they are a bit in a different league though ;-)
more weight = more tyre contact.

Pleiades 22-03-11 18:21
Quote:
Originally Posted by zakidos (Post 151866)
Ok. But how do KTM or BMW handle this issue? I know for sure that with the big 1200GS you don't have this wobbles at 70mph (maybe at a later time). And the KTM 990 Adv shouldn't wobble either. Ok ok, they are a bit in a different league though ;-)
My old 2003 1150GSA used to shimmy like mad at 70mph on TKCs, even worse when they were worn. I think with the Z the biggest contributing factor to handlebar wobble (besides tyres and steering/suspension wear) is the bike has a sizable weight bias to the rear, it's arse heavy, which gets massively worse when you pack it up. I've found (like Peatbog) raising the rear with preload helps a lot, perhaps even dropping the forks a tad may help too?

zakidos 23-03-11 21:09
Quote:
Originally Posted by Pleiades (Post 151869)
My old 2003 1150GSA used to shimmy like mad at 70mph on TKCs, even worse when they were worn. I think with the Z the biggest contributing factor to handlebar wobble (besides tyres and steering/suspension wear) is the bike has a sizable weight bias to the rear, it's arse heavy, which gets massively worse when you pack it up. I've found (like Peatbog) raising the rear with preload helps a lot, perhaps even dropping the forks a tad may help too?
I will definetely investigate in that and try the preload thing as soon as I get time. The wobble is not too bad though, but it's not the best thing either ;-)

mac-cos 25-03-11 11:10
I think its definitely a feature of the ten , due as stated to the saggy as std rear end , most of my miles were higher speed A roads and M'ways (why I changed to an S10) and it used to get a mild head shake on crossing lines /banding etc when pushing on (throttle open) it never developed into a tank slapper and generally sorted itself out, this was on both Siracs and T63s
The S10 is battleship stable in comparision.
PS I think the helmet buffeting the Ten can generate at such speeds doesnt help as it may cause the rider to hold on to the bars tighter too.


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