Hmm ..my recently purchased r1100gs appears to have a knackered rear shock
it was a bit soft when I went to see it and took it a run before buying it I said to the seller about it being a bit soft and he said he'd never touched the settings from when he got it from the previous owner .. anyway went and picked it up from my g/f cos thats where it has been for the last week and I tried the preload and it adjusts but the little screw for damping just keeps turning ..so looks like I'll be on the look out for a rear shock
Just checking some basics before you go out to spend some hard earned cash:
1. You say the pre load adjuster works? Does turning it actually affect the springs compression? If yes then all well and good in that department.
2. Any oil leaks from the shock? No? then that's OK.
3. When you say the damping adjuster screw keeps turning -by how much? On my 1150 GS the screw adjusts 3 full times when turning clockwise between the H and S markers.
(When I bought a used shock from eBay the damping had been backed right off and the bike bounced about like a kangaroo. I didn't realise the damping screw turned several times though you may do in which case you probably do indeed had a problem!!)
I found the following from 2009 which I have copied and pasted here. Hope this may help:
Suspension
The stock R11GS suspension has the following adjustments:
* Front: preload
* Rear: preload and rebound damping
* (There is no adjustment for compression damping although it is affected by rebound damping).
Set the preload first then the rebound damping.
Preload
is the static tension in the spring. It affects suspension travel, seat height and speed of steering but not 'hardness' or 'softness' of the ride (unless you hit the top or bottom stop).
The following ASCII art represents your spring when it:
1. is uncompressed (e.g. on center stand with wheel off the ground)
2. has low preload
3. has high preload
- ---------------------- - ------------------ -
| | |
| | |
| Uncompressed | LOW | HIGH
| spring | preload - preload
| length |
| -
-
Adjustment
Front: Adjust collar on bottom of shock using hook wrench and extension from the toolkit.
There are 5 notches.
Highest notch is LOW;
Lowest notch is HIGH.
Standard setting: second highest notch
Suspension travel: 190mm (BMW claim)
Ideal preload: 1:3 i.e. 63mm of 190mm travel
Rear: Set with large black knob by exhaust marked HIGH, STD, LOW.
HIGHer is clockwise;
LOWer is counterclockwise
Standard setting: as marked STD
Suspension travel: 200mm (BMW claim)
Ideal preload: 1:3 i.e. 67mm of 200mm travel
Set-up:
1. Sit on the bike wearing all your riding gear e.g. jacket, helmet etc
2. Adjust preload front and back so about a third of your suspension travel is used up.
(Helps if you've got someone to measure or else use a plastic tie on the suspension to see how much the shock compresses).
Adjust preload front and rear for:
* increased loads eg touring/pillion go HIGHer
* bumpy roads and off-road go HIGHer
* smooth roads go LOWer.
Turn the adjuster:
HIGHer to:
* increase suspension travel
* raise seat height
* speed up steering.
LOWer to:
* decrease suspension travel
* lower seat height
* slow down steering.
Fault finding:
1. Suspension tops out, bike steers too quickly ("tucks") - preload too LOW so go HIGHer
2. Not enough ground clearance, suspension bottoms out, bike turns too slowly - preload too HIGH so go LOWer
Rear rebound damping
resists spring extending. When the spring is compressed it goes to a minimum length then springs back (i.e. rebounds). Rebound damping stops your *wheel* from bouncing, not you. Affects traction and how the ride feels i.e. "hardness" or "softness".
Rebound damping is connected to compression damping and vice versa. This makes finding the correct settings difficult. If you make rebound damping HARDer, the ride becomes harder but also if you hit a big bump, you are less likely to bottom out (than if you had SOFTer setting) i.e. same effect as if you had increased compression damping.
Adjustment
The rear rebound damping adjuster is that little black screw on the exhaust side at the bottom of the shock. Adjust using the screwdriver and extension from the toolkit.
* Clockwise is HARDer
* Counterclockwise is SOFTer
Only the last few turns towards HARD seem to have any effect.
Standard setting: turn clockwise to fully HARD then undo HALF a turn
Set up:
1. Ensure tire pressure and tread depth are correct and preload is set.
2. Carefully work out original setting and write it down (for reference and so you can change it back if all else fails).
3. Find a bumpy road, the bumpier and the larger the range of bumps ie small to large, the better. (Riding fast around a bumpy corner is best.) A roadside observer can help as well.
Now ride up and down your bumpy road. Start with one extreme setting (say HARD) then the other (SOFT) so you feel the sort of effect rebound damping has.
Feel what the back end is doing - you want firm traction not skidding.
4. Depending on the feel you got, estimate what initial setting to try (eg half way between the two extremes or more HARD than SOFT).
Try many settings (quarter turn) then write them down with their results.
The ideal setting keeps the back wheel most consistently in contact with the road. (It is NOT the smoothest ride, that's underdamped).
Note
BMW shocks go off very quickly - they heat up then stop working until they cool down again. This means, they are different at the start of your bumpy ride to (say) 15 minutes into it. Give them time to cool otherwise you are wasting your time.
Adjust rebound damping for:
* increased loads eg touring/pillion go HARDer
* bumpy roads and off-road go HARDer
* smooth roads go SOFTer
To check settings for luggage/pillion, load up and try your bumpy road again.
Fault finding:
1. Tire won't stay in contact with ground on series of bumps - too HARD so go SOFTer
2. Bike pogoes (bounces up and down excessively) - too SOFT so go HARDer or one or both shock absorbers are worn
Simple shock absorber test
To check the rear shock absorber:
* Start with a visual check - if there is any leaking fluid replace immediately. If not, wipe clean.
* Put the bike on its center stand.
* Sit on the rear seat.
* Put both feet down on the ground and stand as high as you can.
* QUICKLY drop all your weight down onto the rear seat.
* Just as the suspension compresses most, QUICKLY stand up.
(I.e. push the bike down and let the suspension push it back up).
* Watch how the seat moves.
A good shock absorber pushes it back where it was and stops.
A worn shock absorber behaves differently e.g. moves up and down several times.
Try it a couple of times to get the idea.
Apart from the visual check, testing the front shock absorber is not so easy as it is more difficult to compress. However, if the handling deteriorates, the tires and rear shock are ok then suspect the front shock and seek expert help.
bout it but not much I can do now .. hey ho ..
??? think there is a couple of places that do shock repairs up here.. jus need to email them or give them a call .. cheers
thanks itll prolly be fork oil I would think 
