Wobble!

[Soggz]

Hi, new shock,tyres,etc.
Took the bike up a local fast road. Got to 115,mph, still pulling...then Speed Wobble!
Controlled it back down to 90,then turned down a quieter road.
Speed wobble. What caused it please? New Avon Road riders, new shock, new front shock oil and seals...

[Laitch]

Your moto wasn't designed to travel optimally at 110 mph although it just might be capable of doing it. Here's an explanation in your native tongue. :giggles

[natalena]

Have had the wobbles too, and hence, don't use the brick as a "sport 'brats-burner' bike."

I've usually tracked speed wobble down to headset bearing galling/misadjusted, tires underinflated, or what I think is a noodle frame that flexes and builds up a frequency that shakes everything. Probably a combo of little stuff that the steering damper can't quite handle.

It's BMW's method to get you religious for 2 weeks at a time, between spotty escapades.
 

[Soggz]

Your moto wasn't designed to travel optimally at 110 mph although it just might be capable of doing it. Here's an explanation in your native tongue. :giggles

Brilliant. I guess my k75 must be in a better state as the old 80’s bikes featured in the film, as my wobble never started until around 115 mph! New front springs and thicker oil may even help! Great film, though. Thanks for that Laitch, at least my back is finally back on the road where it should be after all this time of getting it to go!

[Soggz]

Have had the wobbles too, and hence, don't use the brick as a "sport 'brats-burner' bike."

I've usually tracked speed wobble down to headset bearing galling/misadjusted, tires underinflated, or what I think is a noodle frame that flexes and builds up a frequency that shakes everything. Probably a combo of little stuff that the steering damper can't quite handle.

It's BMW's method to get you religious for 2 weeks at a time, between spotty escapades.

I have no steering damper, as far as I know...

[The Mighty Gryphon]

The steering damper is in the head. 

[Martin]

It's called a Fluid Block Damper and as Gryph says it's built into the steering head. It is no longer available new and very hard to get second hand. If the problem is only occurring at 115 MPH either slow down or up your insurance. There has been discussions on whether the Fluid Block actually works and some have removed it with no stated detriment. Mine is intact and has been regreased and the few times (not recently) I have run up to 200 KPH with no sign of any shake.
Regards Martin.

[Soggz]

It's called a Fluid Block Damper and as Gryph says it's built into the steering head. It is no longer available new and very hard to get second hand. If the problem is only occurring at 115 MPH either slow down or up your insurance. There has been discussions on whether the Fluid Block actually works and some have removed it with no stated detriment. Mine is intact and has been regreased and the few times (not recently) I have run up to 200 KPH with no sign of any shake.
Regards Martin.

ok, that’s good to know. As far as I know, it’s not been degreased for a while. I didn’t realise that it was in the steering column. Is it easy to get to?

[The Mighty Gryphon]

Do you have an aftermarket fairing or windshield on your bike, especially one that is mounted on the handlebars?  How accurately are your wheels balanced?  Are the weights half-and-half on both sides of the wheel? 

I have had my K75RT up to an actual(GPS) 110mph fully loaded for touring and never the slightest hint of a wobble.  Normally, these bikes are pretty stable at high speed.

[Martin]

Read up on it ( Haynes or Clymer) there are two special screws that engage the damper and the steering head needs to be removed. The grease required is Dow Corning High Vacuum Silicone Grease from memory $50.00 Au a tube. As per Gryph a highly stable bike otherwise I wouldn't still be here.
Regards Martin.

[Laitch]

I have had my K75RT up to an actual(GPS) 110mph fully loaded for touring and never the slightest hint of a wobble.  Normally, these bikes are pretty stable at high speed.

As this video indicates, increased weight tends inhibit wobble.

[rbm]

Did you make any changes to the frame or forks /  swing arm geometry that might have altered the geometry of the bike?

[Soggz]

Do you have an aftermarket fairing or windshield on your bike, especially one that is mounted on the handlebars?  How accurately are your wheels balanced?  Are the weights half-and-half on both sides of the wheel? 

I have had my K75RT up to an actual(GPS) 110mph fully loaded for touring and never the slightest hint of a wobble.  Normally, these bikes are pretty stable at high speed.

Hi. No aftermarket fairing, just as you see in my pic on the left.

[Soggz]

Did you make any changes to the frame or forks /  swing arm geometry that might have altered the geometry of the bike?

all as it left the factory, apart from the new YSS damper.

[Soggz]

As this video indicates, increased weight tends inhibit wobble.

perhaps I  need to gain weight!

[Laitch]

perhaps I  need to gain weight!

You're perfect just the way you are. Ride faster.

[Soggz]

You're perfect just the way you are. Ride faster.

im 5’8” and 12 stone. The shock I just put on is rated for a rider of 12 to 15 stone, apparently... and no one is perfect.(Although, I’m the closest you will get to it...!)...

[Laitch]

(Although, I’m the closest you will get to it...!)...

I'm comfortable with the current distance. It's perfect, too.

[Soggz]

 :hehehe

I'm comfortable with the current distance. It's perfect, too.

[volador]

Classic Chris Harris. Good Day

[Soggz]

Classic Chris Harris. Good Day

Cool. Gotta luv Chris Harris.

[daveson]

Did you have this problem before your recent rear shock change?

Is it possible you installed it, then had fish and chips for lunch, then came back in the shed,  and moved on to other things and havn't torqued it yet?

[Soggz]

Did you have this problem before your recent rear shock change?

Is it possible you installed it, then had fish and chips for lunch, then came back in the shed,  and moved on to other things and havn't torqued it yet?

All nice and tight mate. And I don’t eat fried food, although, perhaps I should, and then I’ll be heavier,and it might not happen again!

[daveson]

Yep, I forgot you're only twelve stone.

If you're confident with the install, look at some other basics. Head stem bearings, wheel bearings, swing arm bearings, wheels spin easy, wheel alignment.

Maybe I'm wrong, I thought the fluid block was only in the k75s.

[Soggz]

Yep, I forgot you're only twelve stone.

If you're confident with the install, look at some other basics. Head stem bearings, wheel bearings, swing arm bearings, wheels spin easy, wheel alignment.

Maybe I'm wrong, I thought the fluid block was only in the k75s.

im guessing it’s in the C model too, as I have found the two bolts that Chris mentioned in the video.