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  #1  
Old 06-02-2012, 03:53 PM
Captainbeaky Captainbeaky is offline
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Engine Mount Failure? Vibration and harshness.

Hi there.

1997, K1200RS.

Bike has been in an accident, LH handlebar and engine case impacted road.
Then I bought it - in it's post-crash condition for very little money.

It handled like it had a hinge in the middle after the accident, and was very rattly and loose. I traced this to damaged lower and upper ball joints - and a displaced front trailing arm bearing. I changed the balljoints and the bearings (and the split breather while I was there !) Top yoke also damaged (smashed lock stop) - so I changed this too.

Forks straight as a die - no problems there - no signs of damage to the leading link.
Wheel bearings fine - wheel is straight and true.

Rear drive is nice and tight - no discernible movement at all (which surprised me - I expected a little play)

She now handles a lot better - positive and tracks nicely through corners - shows absolutely no bias tot he left or right when you lock the back wheel (ABS works fine - I disconnected it for this test).

But there is still a Knock from somewhere when I go over bumps - I feel it in the bars and through the seat - not quite a knock - more of a harshness / rumbling. , and the whole bike feels a bit too "Hard".

Seems to be worse under acceleration too.

And perhaps there is a "Shifting" of the suspension under very hard 1st gear acceleration - although I have only had this once - it may have been wheelspin on a poor tarmac surface.

I was thinking Engine mounts - does this sound right?
(I did jack the whole lot up on the engine when I did the work - ould this have knackered them?

Any advise would be helpful.

Ta,

Mike.
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  #2  
Old 06-02-2012, 05:48 PM
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Re: Engine Mount Failure? Vibration and harshness.

Have you played with the rear preload adjustment? My 03KRS preload was knob was all the way out, giving me no preload and I would hear a sort of clunk. Once I applied more preload, it was better, not sure if its completely gone.
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Old 06-02-2012, 06:13 PM
Captainbeaky Captainbeaky is offline
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Re: Engine Mount Failure? Vibration and harshness.

The 97 krs does not have a preload knob.

Its something that happened in the crash or since.
My mate ( who owned it and was hit off it by another rider) confirmed that it wasnt right.
I have never ridden a k before, so didnt know if this was normal.
He confirmed that it should be smooth as silk, but mine feels more like an old gsxr1100.

Any clues?
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Old 06-03-2012, 05:05 AM
voxmagna voxmagna is offline
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Re: Engine Mount Failure? Vibration and harshness.

Quote:
I was thinking Engine mounts - does this sound right?
(I did jack the whole lot up on the engine when I did the work - ould this have knackered them?

That is what I did wrong and I spent a long time getting rid of a vibration after a motor out rebuild.

First you need to check the exhaust header bolts are tight, then have a good look at the muffler rubber mounting on the rear. The K stock exhaust is a key element in tieing the motor and making it rigid in the frame.

Next look at the front engine mounts and the position of the 'voids' so they do actually support the motor weight and the bolt holes are central. If they are not, then the rubber could have gone soft or been damaged. There is a torque spec. on those front mounting bolts which is important.

Finally, check the oil cooler lines at the front are properly fixed in the plastic clips and are not touching the frame. Also, check there is some clearance around the water hoses and the hose clips are not touching the plastics.

A mechanics stethoscope is your best friend for diagnosing vibrations through the frame.

A mechanical 'knock' is unlikely to be a vibration issue. I would be looking at front/rear suspension and shocks for that. You sometimes hear a lesser knock. (more like a rattle) from the floating rotors on the front when the fixing screw springs have lost their tension. Hold each rotor and there should be some tension as you try to move it around. If there is non and just a clunk, then bend back or replace the spring washers under the fixing bolts.
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  #5  
Old 06-03-2012, 11:05 AM
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Re: Engine Mount Failure? Vibration and harshness.

I know for a fact that the exhaust will vibrate if not mounted correctly at the rear bracket. I ran for a while without the "Spacer" there and did get vibrations, very noticeable if I put my foot on the centerstand when riding. All the spacer is is a green O-ring. Shown as some sort of washer on the parts fiche but just got one and that is what they sent me an O-ring.

So if the bracket got bent in the incident, good chance you may get vibrations there.

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Old 06-03-2012, 11:21 AM
Captainbeaky Captainbeaky is offline
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Re: Engine Mount Failure? Vibration and harshness.

I hadn't looked at the exhaust.
The engine mounts look ok, not sagging or touching.
But I haven't checked for anything else touching.
Its definitely not the suspension. I have been through it thoroughly (hence the head scratching)
It's also not the discs ( had a gs for 8 years) The "rumbling knock" comes through everywhere!
Thanks for the advice. Will start looking.
M.
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  #7  
Old 06-04-2012, 05:35 AM
voxmagna voxmagna is offline
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Re: Engine Mount Failure? Vibration and harshness.

....Also check out your stands, They have rubber 'stops' on the back sides which also act as vibration isolators. If you have metal to frame contact when the stand is raised, that to will be your problem.
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Old 06-04-2012, 07:59 AM
lionheart9999 lionheart9999 is offline
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Re: Vibration

Hi guy's

Just purchased a 06 BMW K 1200 S and feel a vibration in the bike when de-cellerating and the decellerating happens as soon as i release the throttle.

I have just changed out the rear tire and now there is a shaking in the bike. The bike only has 7,000 klms on it and never been in an accident. Really well looked after.

A little dissapointed with the bike as i thought i as buying one of the premo bikes.

Met one guy on the ferry to Vancouver with the same bike and the same problem with the vibration when de cellerating but the shaking after the new tire has just made me park the bike in the garage until i sort this out.

Len
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  #9  
Old 06-04-2012, 09:26 AM
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Re: Engine Mount Failure? Vibration and harshness.

If there was no shaking or vibration before, then logic suggests the problem may be connected to what was last done.

By the way, you are posting in the K1200RS/GT bike section for your 'S'
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Old 06-06-2012, 10:43 AM
Captainbeaky Captainbeaky is offline
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Re: Engine Mount Failure? Vibration and harshness.

The exhaust rear mount had no apparent rubber O-Ring in it - I have put in a standard black O-Ring - although, I wonder if this will really make much difference, as the top of the exhaust hangar is a rubber coupling anyway - this appears in good order. header bolts are all tight. I have inspected all around the exhaust, and it isn't touching anywhere.

I have re-inspected the mounts as much as I can without tearing the whole bike apart again. They are nicely centred in the mount - there appears to be no sagging at all, and no metal to metal contact. There is a little flexibility in there - they are fairly stiff mounts.
I cannot see the "void" in the front mounts without disassembling them.

I have closely examined all the oil pipes etc,. - none are touching the engine, and all appear nicely centred.

The centre and side stands still have their rubber buffers present and working.

So I am still a bit confused.

The bike simply feels gruff, and there is a "rumbly knock" when I go over bumps.

Feel and handling is much improved with the new front tyre - but the bike still feels "rumbly"

Any other clues would be gratefully received.
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Old 06-06-2012, 10:55 AM
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Re: Engine Mount Failure? Vibration and harshness.

Rumbly? Driveshaft ???
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  #12  
Old 06-06-2012, 11:09 AM
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Re: Engine Mount Failure? Vibration and harshness.

Capt'n
You seem to be doing a most excellent job of sorting things out.

Might I suggest now that you find a good example of a K-RS to ride. It might help to use as a baseline of feel/sound/vibs/clunks or lack of etc. Then you might better know if you are truly chasing a problem or it is the nature of the beast.

NCS
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Old 06-06-2012, 01:13 PM
Captainbeaky Captainbeaky is offline
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Re: Engine Mount Failure? Vibration and harshness.

I thought about the driveshaft too - but the rumbling isn't present when on the side stand, in gear with he back wheel turning at speed.

Have just got back from a ride.
Now that the front wheel has scrubbed in, I can explore the handling a little.
It tracks nicely - the roughness isn't in the suspension at all.

But on closer inspection / with more experience riding it, there appears to be two separate issues (but this doesn't mean it can be the same issue)

1. A definite "something clonking" in the suspension department. it feels a bit like a balljoint worn, or trailing arm bearings (but they are all brand new). particularly in the LH handlebar - a disconcerting clunk felt through mainly the LH bar - but having been throughout he front end with a fine tooth comb, I can feel no play or wear anywhere.
It isn't disc or pad rattle - it feels higher up in the forks.
It is disconcerting rather than affecting the handling. A mid-corner bump does not alter the bikes line at all.

2. Engine vibration coming through everywhere - Bars and pegs - suggesting that the engine is grounding to the frame somewhere - but I'll be buggered if I can find where.
Again, this does not seem to affect the handling at all.

Yes - perhaps I should try a good one and see if it's me!

Anyone got a good one in Gloucestershire that they would be willing to let me try?

Thanks,

Mike.
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Old 06-06-2012, 03:27 PM
voxmagna voxmagna is offline
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Re: Engine Mount Failure? Vibration and harshness.

You never said you had checked the oil cooler lines at the front?

I thought there was something strange about those front mounts. There has been some post about making sure the front bolts were at the 'correct' torque to reduce vibes, which I never understood at the time.

If you look at what they are supposed to do (mount and kill vibration) then on my bike something was wrong. To do the job the inner sleeve and bolt must have no contact with the outer bush. Well on my bike they had a large washer which just went flat across the inner and outer bushes. No good for anything. Then I remembered about the torque thing and I think that is just a way of tuning out the 'short circuit' produced by their washer. I found all this with the mechanics stethoscope. In the end I either sourced a slightly smaller OD washer or ground down the oem so it would only make contact with the inner bush.

Get a cheap mechanics stethoscope as it will save you a lot of time - it took me ages to work through all the possibilites. There is also a rear support mount which is part of the transmission housing.

We have road humps and I am a little more aware of some front end noise now, but no handling issues. I have a pair of new oem shocks and intend to pull the lot apart and have a good look, since nothing has been touched since 1997. I've just been putting off the ball joint job and shall wait until the season cools down. Mine all looks a bit dirty and rusty up there.
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Old 06-07-2012, 12:50 AM
snowy1248 snowy1248 is offline
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Re: Engine Mount Failure? Vibration and harshness.

This happened to me when the bike had a slow speed fall over. I would try to ride and had a "knock" in the front end and it felt weird. I could ride the bike but didn't have a lot of confidence in it. When I finally got it home, it was trucked from Wisconsin to Colorado, I went over it with a fine tooth comb. The front end had a slight looseness when I would grab it and move it on the center stand. it turned out to be the pinch bolt on the front end A frame. It had come loose and the A frame was pivoting on the cross rod but was loose. I used a long extension plus another and a 6mm (I believe) allen socket to tighten it and the knock and wobbly went away. The pinch bolt is not easy to see and if you aren't looking for it will probably miss it. I only found it after looking at the parts fiche in desperation. I have never heard of anyone else with this issue but it is definitely worth checking out especially after what has happened to your bike. Mine was a salvage bike I rebuilt and the pinch bolt probably was loosened in its previous crash.
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Old 06-07-2012, 06:24 AM
voxmagna voxmagna is offline
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Re: Engine Mount Failure? Vibration and harshness.

That is new and I've not seen it posted before.

Any chance of a pointer to the part reference on Realoem to make it clearer?

http://www.realoem.com/bmw/showparts...&hg=46&fg=0 5
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Old 06-07-2012, 07:39 AM
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Re: Engine Mount Failure? Vibration and harshness.

I've no experience, but it sounds like #4 here:
http://www.realoem.com/bmw/showparts.do?model=0544&mospid=51718&btnr=31_0353&hg=31&fg=1 5
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  #18  
Old 06-07-2012, 08:32 AM
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Re: Engine Mount Failure? Vibration and harshness.

Quote:
Originally Posted by snowy1248
This happened to me when the bike had a slow speed fall over. I would try to ride and had a "knock" in the front end and it felt weird. I could ride the bike but didn't have a lot of confidence in it. When I finally got it home, it was trucked from Wisconsin to Colorado, I went over it with a fine tooth comb. The front end had a slight looseness when I would grab it and move it on the center stand. it turned out to be the pinch bolt on the front end A frame. It had come loose and the A frame was pivoting on the cross rod but was loose. I used a long extension plus another and a 6mm (I believe) allen socket to tighten it and the knock and wobbly went away. The pinch bolt is not easy to see and if you aren't looking for it will probably miss it. I only found it after looking at the parts fiche in desperation. I have never heard of anyone else with this issue but it is definitely worth checking out especially after what has happened to your bike. Mine was a salvage bike I rebuilt and the pinch bolt probably was loosened in its previous crash.

As RACINGIRON said, I believe you are referring to bolt item #4 in the parts diagram of the A-arm front suspension (see picture 1 attached to this message).

I just went into the garage and took a picture of what it looks like. It is located on the right side of the bike, on top of the engine, behind the front engine-mount. Not easily accessible, but can be checked from a view between the front-fork, even without removing fairings. You will need a good light to beam into this cavity (see picture 2 attached to this message).

Using 2 extensions (total length 11.5 inches) and a 6mm Allen bit, I was able to reach it and check that mine was nice and tight. You will need to insert your extension just above the engine, working from behind the rear of the front fender (the black plastic section of the fender). I suspect it would be easier to work on it with the fairing and the fuel tank removed, but it is possible to do nonetheless.

The BMW shop manual does not offer many pictures of the A-arm, but the Clymer manual does. As this is a critical component of the front suspension, I had always assumed that everything would be mounted with thread-locking-compound. But the poster SNOWY1248 just gave us a good tip - better be safe than sorry - thanks!
Attached Images
File Type: jpg K1200RS_LeadingLink_Aarm_Parts-diagram.jpg (48.4 KB, 14 views)
File Type: jpg K1200RS_LeadingLink_Aarm_Pinch-bolt.JPG (47.4 KB, 28 views)
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  #19  
Old 06-07-2012, 10:57 AM
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Re: Engine Mount Failure? Vibration and harshness.

Thinking out loud. If way off base the gurus can gently chide me.

If you are getting this clunk in movement of suspension. Could you undo the mount on the rear shock /swing arm and then see if you can feel the "clunk" when manually moving the rear through its arch of travel.

The front would be more cumbersome but might be done also. We are making the assumption that the internal workings of the shocks are not compromised and that the springs are without any damage.

Might there be something overly tight and binding and the clunk/harshness you feel is actually the resistance of the moving parts forcing movement?

I think the rear shock even on the older models had rear preload adjustment but it was via a ring. Also damping adjustment was by a screw.

The engine vibration thoughts keep going back to.

1) that the engine really is OK and not some number 1 connecting rod failing.

2) that the vibration really is at normal limits (as I know if I rest my toe on the center stand lever while riding I am astonished at how much is it vibrating compared to the rest of the bike, and hard vibration, nothing subtle ).

3)thus it is something in how the bike was crashed, suspended and put back together.

Thus, you have said you have visually inspected the mounts as best you could. It may be time to remove parts and get to them just as you have the suspension to verify their soundness/tightness/mechanical integrity .

Ok.. thats the thoughts of one less skilled. Good luck

Now if you came near here, I would let you ride mine.

NCS
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Old 06-07-2012, 11:06 AM
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Re: Engine Mount Failure? Vibration and harshness.

You are welcome to have a go on my '97 K12RS so you have a benchmark of what a good one should feel like. I'm in Goole, 1 mile off the M62. PS my handlebars have come slightly loose before now, despite being carefully torqued to 20Nm. Worth a look on yours. David Mc.
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Old 06-07-2012, 02:48 PM
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Re: Engine Mount Failure? Vibration and harshness.

Hi there,

Thanks for all the advice.

The clunk is related to the front suspension. I've had it to pieces. The fork sliders are smooth and sweet. the trailing link is now smooth as silk.

The only thing I haven't taken apart was the spring from the front shock.
Inspected it - no leakage etc,. Didn't consider it as prone to damage, as the big sideways loads are taken by the forks and the front link/balljoints.

I've had the front leading link out, and changed the bearings.
The impact had displaced the RH bearing, and the bike was handling like it had a hinge in the middle!

I've changed these bearings anyway (getting them in and out is fun! - it starts by removing the fuel injection bodies!) Both Balljoints have been changed - as has the top yoke.

The front wheel bearings are OK.

She's handling fine - not a great deal of feel, i have to admit, but she tips into the corners nicely, and doesn't shift around when adding power, or hitting a bump. The previous odd back end feeling was definitely wheelspin - this is the most powerful bike I've ever owned - boy does she go - and the power is soooo linear!)

It's just this annoying rattling rumbling looseness that I just cannot pin down.

I have had my stethoscope out, and the front engine mounts do seem to be transmitting a bit of noise across, but there is a huge difference in noise levels between the engine and the frame - so the isolator does seem to be in there. There is a healthy gap around the mount bolts etc, nothing touching.

Yes, I did check the oil cooler lines.

It's definitely something caused by the crash - but what???


It does sound like there's rocks in the gearbox - but they all do that - and I've had it at very silly speeds - the engine wouldn't have endured this thrashing if it was on the way out - it would have been an oily smoking mess.

I've got the plastics back on it at the mo - I want to use it for a few days - then I'll whip them off again, and have another look.

In the meantime - if anyone has any ideas...

Thanks,

Mike.
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