I just finished doing my annual winter oil change, when I noticed that the rear shock had emptied its contents over the back wheel. It also had no resistance to movement = knackered shock.

In my Hayes manual it gives specifications of spring length and spring wire diameter but says Except K100LT. Does this mean that a K100 shock is not the same as one for a 1992 K100LT? (Note I do not have the Nivomat self levalling unit)

I have looked for a used shock and have ordered one from ebay as much cheaper then new unit. But now I am not sure that a K100 shock is the same.  Any advice or source for correct shock is welcome.

I think some of the later LTs had a different Boge shock.

However, the frame/final drive is the same so a used shock from another K should work fine.

http://www.realoem.com/bmw/partxref.do?part=33531450850

The price of shocks is shocking. I'm in desparate need of a new one. The cheapest i can find it the realm ram shock (£245) which comes highly recomended, not just for value but also quality... I'll have to see what Santa brings (I'v dropped enough hints)
I would'nt consider fitting a second hand one as its likely to be at least 20 years old with a fair few miles on it (mines only done 46k and its shot)

If you do NOT have a Paralever rear suspension then andy of the early K100 shocks will work.

Paralever suspensions require a longer shock.

Englishkent wrote:
I would'nt consider fitting a second hand one as its likely to be at least 20 years old with a fair few miles on it (mines only done 46k and its shot)

Not all second-hand shocks are as old as the bike they came from. I got a nice Fournales air shock second-hand. I've seen others on 'tinter-net like RAM, White power, Hagon etc for sale which are obviously newer than the bikes they came from.

Try James Sherlock in Devon. They will supply a new Bilstein damper unit for £112.80.
Easily changed with a small cold chisel and a big hammer. I've done it!
Gives you virtually a new original shock. Don't forget to paint the spring while you have it apart.
My current RT came with a Hagon. Only marginally better than an original.
All the monolevers take the same unit. Don't buy a 2nd hand Boge (Nivomat). Too old now.

I received my used shock and have fitted it. So far so good. Now that I have a spare bust one I will visit Sherlock (when I next go to Exmoor) and see if I can replace the damper myself with a new one  That would be the best for the future.

I would be grateful for any advice on how to change the damper in the unit - I am thinking of using luggage straps to compress the coil to so i can undo the end off the damper shaft.

Don't worry,  replacement damper comes with instructions. You use a small cold chisel to remove the tabs on the damper body that the adjuster rests against. Shock then dismantles.
Put the damper rod in a vice and unscrew the eye end.
Not sure if you can compress the spring with straps. I borrowed a pair of small car spring compressers. The eye end is then screwed back on to the damper rod  using Loctite on the threads.
Give the spring a lick of paint while it's apart.