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I ride a 2004 K1200GT and am running Dunlop RoadSmart tires that have served me well. My bike has 23,500+ miles and just came out of a BMW Dealer performed 24,000 mile service.

My tires are pretty worn with about 9,000 miles and are almost to the point the center tread will be gone. The front tire has some light cupping. I am holding off buying new tires as long as possible because I am riding to the BMW MOA Rally in Redmond this July from Houston, TX and my planned route is just under 5,500 miles.

The Issue. This weekend at the beginning of a 300 mile ride there was no issue. However, later in the trip if I attempted to set the cruise control for no hands riding the front wheel (handle bars and all) shook violently back and forth. With my hands one or both bars there was slight vibration but in no way dramatic.

Is this a symptom of a worn-out steering damper?
 

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No... Sounds like a wheel or tire.. or tire weight issue. Check to see if you've thrown some tire weights off...it happens...

FYI.. the factory dampers are generally good for 30-35K....

GMAlley said:
Is this a symptom of a worn-out steering damper?
 

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The 'standard test' to induce steering wobble I came across on a site where a guy deliberately introduced front steering wobble was to accelerate to around 60mph, take hands off the bars, let the throttle roll off and during the decel phase, if the front was going to wobble it would do so.

Now that sounds a bit hairy so 'don't try this at home'! But he was testing shorter wheelbase ricers that had to have working dampers to keep them stable - a bit like fly-by-wire planes.

The heavy K bikes are longer wheelbase and not usually known for front steering wobble instability, even though BMW fit a wobble stopper (which isn't the same as a progressive 'damper').

Even though I know my damper is ok and only comes in at about +/- 10 degrees of 'wobble', I've never had what I could say was a wobble with decel or side winds and even with a good damper I would have felt the onset. My tires are never down to the chords - that would be illegal over here.

BMW probably fitted the wobble stopper for some rare event that it might happen.

I'd suggest that rare event could be badly worn tires and it would be unfair to blame the last resort action of a working steering damper to put that right. If you put the bike on the centre stand then move the steering rapidly from side to side and feel no resistance the damper isn't doing anything. You can get more 'feel' if you get the front wheel off the ground an inch, straddle it and move it lock to lock.



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Re:

Back off and look at the front tire, the cupping makes the middle of the tread look like a zig-zag ridge of rubber. Road imperfections cause the tire to wander around. Mine usually act up around 25mph, 50-60 they will still track true.
 

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Well you said the front tire is cupped, so that could cause the wobble.
New balanced tires should take the wobble out.
But I have also found that this bike’s shocks are worn out at 20,000 + miles. and if after you put a new set of tires on and the bike still does not handle well it may be the shocks.

I chased that bad handling on my first bike and it was the shocks. So when my 2004 got to 22,000 mile and handled like a HD I got me an aftermarket set of shocks.

One more point; I run Mich PRII and after 11,000 miles the front was worn to the wear bar.
I replaced with the same make model tire and I had a steering wobble a 45MPH with no hands on the grips. Result bad tire!!!

Pat Clark motorcycles of Las Vegas check the wheel and tire out and found nothing wrong. I just said to the manager, “I will have to buy a new tire because that one is no good”.
The manager gave me a new tire “no charge” and the wobble is gone.

Pat Clark Motorcycles is a stand up company!!
 

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GMAlley said:
I ride a 2004 K1200GT and am running Dunlop RoadSmart tires that have served me well. My bike has 23,500+ miles and just came out of a BMW Dealer performed 24,000 mile service.

My tires are pretty worn with about 9,000 miles and are almost to the point the center tread will be gone. The front tire has some light cupping. I am holding off buying new tires as long as possible because I am riding to the BMW MOA Rally in Redmond this July from Houston, TX and my planned route is just under 5,500 miles.

The Issue. This weekend at the beginning of a 300 mile ride there was no issue. However, later in the trip if I attempted to set the cruise control for no hands riding the front wheel (handle bars and all) shook violently back and forth. With my hands one or both bars there was slight vibration but in no way dramatic.

Is this a symptom of a worn-out steering damper?
there are many things to look at...tire weight missing?...wheel bearings worn?....pinch bolts loose?....a bad belt?...tire press?......dragging caliper?.... ect ......A worn tire shouldn't cause what you describe...
 

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Shock question -

My 2004 K1200GT has the OE shocks - I noted in this thread that the stock shocks are frequently 'toast' after 20,000 miles?

1. Why? Automotive shocks often last 100,000 miles or more? :confused:
2. If this is true - which aftermarket shocks have been found to be optimal for this bike?

Still learning......
 

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My '97 still has the oem original shocks at 38K, but I do have a second pair of oem take offs waiting for me in my workshop.

They still 'work', I am mainly a street/city rider. There is no oil leaking, no rattles or play, they hold up the weight of this heavy bike and the tires wear OK. The bike still goes around corners as fast as I want it to. If I rode the bike a lot harder (difficult in UK), was a heavy burger eating guy, or put it on tracks, I'd probably go with the crowd on replacement shocks.

Now many will say my shocks were toast several years ago!

The aftermarket shocks of choice are Ohlins and Wilburs. Both have the advantage of being able to be repaired/re-built and I guess if you are shocks picky and sensitive, that could be important. When I am riding with a pillion, I am not sure if hot shocks would make that much difference. If it's a softer ride you want, then just get gel pads put in the stock seat.



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I wonder if it depends on the riding and manufacture time. I changed out my OEM rear at about 50,000 miles. It wasn't bad but I was starting to get a bottom out on some bridge edges that I hit everyday that I didn't remember the "bang" of that happening. I bought one off a wrecked bike with 5500 miles. There was a nice improvement. Now 12,000 miles beyond that switch, (supposedly total of about 18,000 on this rear shock) the bike lacks that super solid line feeling in wavy corners. Of course the front has 62,000+ on it now. This isn't a bad insecure feeling at all, just not an on rails feeling. So among other things this winter, figure I will renew the front and rear shocks. Considering Hyperpro at the moment.

As for the steering damper, I still have the OEM one. This past winter on 20 -35 F degree days, doing a box turn into where I park you could really feel the resistance of the oil when moving the bars lock to lock quickly. However, I had to re fasten a glove the other morning going 45 mph. I set the cruise on our dead end road going out. As I was doing this there is a dip I hit every day. There is never a quiver etc. However, with hands off the bars an oscillation started and quickly built bigger rather than stop.It stops as soon as one hand is back on the bars. It was time for new tires etc and new pivot bearings in the rear. So I played to see just how this could be reproduced. It centers right around 45. I hand slap the bars kinda on top at 45, no hands on bars and the movement begins and builds. If at 40 or 50, there is a quiver that stops in about 6-8 cycles. At other speeds none.
I changed the tires and bearings. No change in the quiver. One of the guys at the shop says his GS has the same thing at the same speed. I have played some with the shock setting but it really hasn't changed it. I guess if we had a 20 degree morning this week that would help. Since it is only at one speed I most likely will consider changing it after the weather cools and begins to warm again.

NCS
 

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You are doing the things to set up a wobble, although I also read a decel. from those speeds can bring it on - but mostly on lighter short wheel base sport bikes.

However, It is unusual to hear of this happening and be repeatable on K bikes. I don't think the oem wobble stopper is mean't to smooth out a regular event wobble, but to take care of a combination of rare events that could set one up.

I think I'd still keep looking for something else, because there are many who choose to ride without the damper and I haven't read they can repeatedly set up a wobble. Do you have any bags or cases and is the rear wheel stock size with the spacer fitted?

The oem wobble stopper has a centre dead zone where it does nothing. If yours has lost some oil, then I suspect the dead zone could get bigger, but as far as I know it's unusual to read of any wobble effects.



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the slap to induce the wobble is much like a high setup hit for volley ball but downward. not much forward, just a little bit, mostly straight down. At 45 it does the same as the dip on the road. A small wiggle that then grows larger. Easily dampened with a hand back on the bar. I will change the shocks this winter, check the fit and workings of the front end. Since it is easily reproducible at only that speed, only when induced by something with hands off I am not too overly worried about it. I haven't noticed any oil around the steering damper but then again, it is 7 yrs old and 62,000 miles and only holds a little fluid so it could be at fault.

I would be interested to see if other K RS/GT owners have a similar response at that speed with some slight handle bar imput with hands off.

NCS
 

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I rebuilt mine 3 years ago. Allowing for that dead zone where nothing happens, I can definitely feel it working lock to lock and it feels the same as when I rebuilt it. I could see that the no damp dead zone is part of the design, although low oil could increase it. If you can imagine the piston rod with a piston on the end that slides a short distance on the bottom of the rod between 2 stops, that's more or less how they do it.

If they do leak any oil from the seals, that can get replaced by water that gets sucked in which is lower viscosity. The damper soon goes internally and parts can rust.

But I'm also interested in others repeating your test.



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Hey Vox, my damper is toast. 25% of travel R to L and no damping at all, L to R damping immediately. Also, a build up of oil film on the back side of the stroke. The mounting on the bottom yoke is also toast with 20 mm of movement side to side when wiggling the shaft when fully extended. (no pun intended :teeth ) I have priced up an Ohlins at about 500 notes that is pretty expensive, BUT it is a proper adjustable damper and not a simple wobble stopper as fitted. Is there much work in rebuilding them, and, in your opinion, given that I ride pretty hard, would the investment in an Ohlins damper be worth the expense, given the long wheel base and fork rake? The Ohlins shocks are set up perfectly, but high speed cornering quality has diminished a little - or am I just riding harder now :teeth Maybe a rebuild will be enough.... Appreciate your thoughts :clap:
 

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Hey Das, I am working through the options with the Ohlins guy here and will let you know the outcome. I believe Ohlins no longer have a specific part number for our bikes but there are other options that can be adapted. I will be keen to see what Vox has to say on the subject as it costs a fair bit of coin to replace it, and it needs to be beneficial.... How is your handling issue? Did the front tire air pressure sort the problem?
 

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flyingkiwi said:
Hey Vox, my damper is toast. 25% of travel R to L and no damping at all, L to R damping immediately. Also, a build up of oil film on the back side of the stroke. The mounting on the bottom yoke is also toast with 20 mm of movement side to side when wiggling the shaft when fully extended. (no pun intended :teeth ) I have priced up an Ohlins at about 500 notes that is pretty expensive, BUT it is a proper adjustable damper and not a simple wobble stopper as fitted. Is there much work in rebuilding them, and, in your opinion, given that I ride pretty hard, would the investment in an Ohlins damper be worth the expense, given the long wheel base and fork rake? The Ohlins shocks are set up perfectly, but high speed cornering quality has diminished a little - or am I just riding harder now :teeth Maybe a rebuild will be enough.... Appreciate your thoughts :clap:
Hi, I'd be surprised if the stock wobble stopper has such an affect on your high speed cornering as from what little I know of the way it works, it would be in its 'dead zone' doing nothing. That suggests to me that other things like tires and suspension setup might have more effect. But if you think you are just pushing the limits of the bike further than most, you might need to get into the whole sport/track rider setup thing with deep pockets.
but I don't do track riding so it's probably best for others to chime in.

I'm not sure if you are saying the bike has an issue with 'fair road use' or you are pushing the envelope with better shocks and seeking a 'fine tune' on the handling. It's always difficult after you start changing things to do the diagnosis and I don't know if after changing to Ohlins there's another 'layer' of tweaks (or tires or wheel balance?) needed.

The long wheelbase, forks rake and weight is what gives the K-Bike its stability, but makes it not so flippable into corners and turns as the lighter short wheelbase ricers.

Even if you repaired the stock wobble stopperer, I don't think it will make much difference and I would eliminate other possibilities first.

Years ago I wanted one of my road cars to go faster. I did some engine tuning and fitted really wide wheels on it. It stuck like glue to the road and did go faster, but when I wanted 'agility' from it - fast cornering etc, it was still the same old car, but with a false sense of improvement!



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Hey Vox, I hear where you are coming from - at the end of the day, this is an over weight sports touring bike trying to mix it with the super light sports bikes! I agree with what you say about the 'dead' zone when very little is happening as far as the damper is concerned. I think I may need to tweek the suspension a little further, or realise that I am demanding more from the chassis than it can deliver... However, either way, the OE damper is toast and needs attention.
 

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Kiwi, I took off my damper and found it useless, its very weak and has very little compression/rebound left in it. But that was during my diagnosis of my wobble I had at high speed.... with it on or off the bike felt the same and I never had a bike with a damper on it so I knew that it wasn't the cause of the wobble.

Was tire pressures, preload, etc... bike is now solid as a rock ! thanks for asking broski from down under :beer:
 

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To all with interest in this thread, I have posted my question to Robert Taylor of Crown Kiwi Technical Ltd, importer and supplier of Ohlins in New Zealand, and through whom I purchased my shocks. Robert is very involved in the racing scene in New Zealand, and has been for many years. As an engineer, he is very quallified on the subject. His response - unedited - is posted with permission... Its brutal but then we have broad sholders :teeth
Q: Hi Robert,
Enquiries from contacts on international BMW sites tell me that a rebuild is all that is necessary as this is not a sports bike that really can use the benefit of a damper. Many riders have removed their 'wobble stopper' without ill effect. It is only there in the case of the big event where it may reduce the onset of a major tank slapper. Thank you for your time and patience, but I will explore rebuilding it, possibly with your help if it is beyond the scope of technical expertise in Wanaka.
Regards,

A: Hi Richard
Cynically, everything is “correct” thats posted on the internet, especially by the keyboard warriors with heaps of idle time that inhabit forums! I am replying as an engineer rather than as a budgeting service!

Maybe it sounds brutal but 99% of these guys know very little about suspension or steering dampers and the engineers that do generally stay away from such forums as all too often the brutal truth is scathingly ‘’shot down’’ by the 5 minute experts who only think like accountants!

I totally beg to differ that a steering damper is less necessary on a touring bike than on a sportsbike. The steering damper should never be there as a “wobble suppressor” to ‘’bandaid’’ the negative affects of bad suspension, geometry or tyres. It should be there as a safety device to stop handlebars being wrenched out of your hands should you hit a pothole or a huge bump, and we have those in abundance! ( Much moreso than where these keyboard jockies primarily habitate ) Also if you run off line etc.

At 100,000 ks with no oil change the internal wear surfaces of an engine would look pretty sick. That will be no less so for your steering damper. Even If you could find suitable seals for it the body tube will be worn out of round and scuffed up as will be the piston etc. So it will be lot of time consuming and frustrating mucking around for ( frankly ) a lousy end result. Bear in mind also that such dampers have no temperature compensation for oil heat expansion so you have to have a small air bubble to allow for that. The negative affect of that is that it further enhances the cavitation that occurs on stroke reversal, because the damper is so cheaply built its not pressurised to preclude such cavitation. That undesirable by-product really hurts damping response

The Ohlins damper is pressurised and absolutely does not cavitate on stroke reversal. It also has a highly refined progression curve, plus external adjustability. In short there should be minimal resistance at “low speed” handlebar movements but there should be progressively more resistance (within clearly defined limits) as the deflective moments incurred into the handlebars become more abrupt.

If I placed you on 2 bikes with bike (1) a brand new BMW damper and (2) Ohlins damper you’d be amazed at the difference in feel.

The forum jockiess may have told you what you want to hear in terms of how it affects your pocket but they are wrong wrong wrong.

As a term of reference Id be interested to know what the price is of a new BMW steering damper...........

Regards
Robert Taylor
 

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That was useful information.

I'm not a keyboard jockey, but as an engineer I have dismantled the BMW steering 'damper' and the 'no damp zone' of about 10 degrees does appear to be part of the way it works, because the piston is allowed to move between two stops before meeting fluid resistance. Is Robert familiar with the design of this BMW component?

Most true steering dampers don't work like this, aiming to control the damping whether progressive or not from the initial point of movement. If I had seen this BMW damper for the first time I would have said it had an air bubble through loss of fluid and was faulty.

If you are considering a true damper such as the Ohlins which Robert claims will change the whole feel of the bike, then he is effectively saying the BMW design is insufficient to do the job. That might be true if the bike is set up without defects and pushed further than most riders would want to go. It might also smooth out defects which the bike now has.

He is right to point out the problems of internal wear when considering if the oem damper should be rebuilt and there are many reasons why it shouldn't be done. When that damper loses oil, the consequence is water gets pulled in causing internal corrosion. But when considering the price of an Ohlins or Hyperpro aftermarket, some consideration might be given to the condition of the oem part.

Give Robert the price of a BMW damper, also tell him the price of the Hyperpro and since we are excluding labor, the price of a seal for the oem if a repair is attempted (no liability if it goes wrong!) is about $5-$10.

The question of whether K-bikes suffer from steering instability might be a good one to get a community vote on, as reported instability problems on K-bikes with or without the oem damper fitted seem quite rare. This should exclude any major changes to the oem suspension setup, but many here are riding with Ohlins or Wilbers shocks.



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