Author Topic: 93 K75S - Handlebar vibrations/oscillations  (Read 9249 times)

Offline GasStation

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  • 93 K75S Mystic Red
93 K75S - Handlebar vibrations/oscillations
« on: April 20, 2012, 11:18:00 PM »
Do your handlebars start shaking in resonance, that is the amplitude increases unless corrected by holding them, when both hands are off the handlebars while riding?

I know, I know, I don't/shouldn't ride without my hands off the handlebars.  :lol:  :loco:

I had both hands off only a few inches above the other day and some sort of rattle or shaking left to right was rapidly developing to the point that if I did not intervene, the front end would have went into self destruction.

Any thoughts on what is the origin of this? Steering damper? Bearings? Fluid bloc assembly? Front wheel? Forks? :confused:
93 K75S Mystic Red
IBA #9469

Offline frankenduck

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Re: Handlebar vibrations/oscillations
« Reply #1 on: April 21, 2012, 12:29:19 AM »
It would help if you put your year/model in your profile sig. (Hint, hint.)

Usual suspects are:

Tire tread cupping.
Loose steering head bearings.
Weights fell of and your front tire is out of balance.
Once I had a Collie pup. Dug a hole and covered him up. Now I sit there by the hour. Waiting for a Collie-flower.
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Offline GasStation

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  • 93 K75S Mystic Red
Re: Handlebar vibrations/oscillations
« Reply #2 on: April 21, 2012, 07:06:18 AM »
It would help if you put your year/model in your profile sig. (Hint, hint.)

Usual suspects are:

Tire tread cupping.
Loose steering head bearings.
Weights fell of and your front tire is out of balance.
Done, it was late. I rarely omit that important detail. Thanks.
93 K75S Mystic Red
IBA #9469

Offline mystic red

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Re: 93 K75S - Handlebar vibrations/oscillations
« Reply #3 on: April 21, 2012, 04:09:34 PM »
No GS, Duck meant in your signature, located under your profile, then on the left click on "forum profile" and type your bike year/model in the signature box and then click "save profile" at the bottom of the page. Then you won't have to remember to start every thread with it. :biggrin: Unless you just want to.

Offline GasStation

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  • 93 K75S Mystic Red
Re: 93 K75S - Handlebar vibrations/oscillations
« Reply #4 on: November 04, 2012, 12:53:47 AM »
I am going to revive this topic since the handlebars are surprisingly quick to vibrate out of control unless there is weight on the bar ends, ie. my hands.

The tires do not show any unusual tire wear. The front tire still has the balancing weights. I am not familiar with the possible steering bearing being loose or warn out. Is this normal for a bike with 45,000 miles? What about the fluid bloc steering damper. I did muck around in the area last winter. Could it be that the fluid bloc assembly moved and is causing this type of resonance?
93 K75S Mystic Red
IBA #9469

Offline wmax351

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Re: 93 K75S - Handlebar vibrations/oscillations
« Reply #5 on: November 04, 2012, 01:33:23 AM »
I am going to revive this topic since the handlebars are surprisingly quick to vibrate out of control unless there is weight on the bar ends, ie. my hands.

The tires do not show any unusual tire wear. The front tire still has the balancing weights. I am not familiar with the possible steering bearing being loose or warn out. Is this normal for a bike with 45,000 miles? What about the fluid bloc steering damper. I did muck around in the area last winter. Could it be that the fluid bloc assembly moved and is causing this type of resonance?

Fluidblok is pretty useless at speeds. Its really only for low speed.

Was the tire balanced when it was put on?

Steering bearing could do it. Or just dried grease in the steering bearing.

Bent frame/forks/etc is an option. Has it been crashed?

Steering bearing is the most likely option. Could be loose, Worn, or have dried grease.

A K75 should be completely stable at all speeds.
  • Albuquerque, NM
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Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Rick G

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Re: 93 K75S - Handlebar vibrations/oscillations
« Reply #6 on: November 04, 2012, 01:44:20 AM »
I have seen an underinflated front tire cause it.

Offline ReneZ

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Re: 93 K75S - Handlebar vibrations/oscillations
« Reply #7 on: November 04, 2012, 04:15:08 AM »
Indeed, with a resulting cupping of the tyre.
Greetings, Rene

BMW K100 - 1984
BMW K1200GT - 2003

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