some tips.
Don't bother looking for the BMW specified fork fluid, the last drums of that old Mil-spec aviation hydraulic fluid were sold a decade ago. Dexron III is in fact the permitted replacement in aircraft that used it so you could be confident that it would meet BMW's specifications.
BUT, unless roads are bowling green smooth where you live, it is way too light. (Drum Roll) I recommend Castrol Fork Fluid 5 mixed with Fork Fluid 10 to taste. I weigh north of 120kg and find that a 50/50 mix is appropriate for my style of riding. You may well find that straight Castrol 5 is sufficient on its own.
The stock springs are too light also, drop a collar normally used on the centre stand pivot bolts onto the top of each damper rod to give yourself a handy 1/2" of preload (or visit a motorcycle wrecker and buy a bent, hollow, set of handlebars annd use whatever straight bits remain to cut yourself some new preload spacers.
Ignore any mention in any so-called service manual that talks about pulling your damper rods out of the top of the forks (or worse putting them back in via the top)
Damper rods come out and go back in from the bottom of the forks - you will need a good internal circlip plier.
You can bet that the rebound cushion stops are either no longer there, or have turned into red "goo" at the bottom of the forks - buy new ones (
http://www.motorworks.co.uk) arer one of the few who still have them - apparenlty there is a similar device that fits in K bikes that can also be used.
For the small cost involved buy 1 or 2 spare damper piston rings and hand on to them against need - over the years I have pulled a lot of R65 and R80ST forks apart and found a lot of missing damper piston rings - usually a result of the last person to work on them trying to force them in from the top of the fork, buggering them and then deciding to not wait for replacements.
If you don't have the crush washers that seal the fork drain bolts and the bolt that both holds and seals the slider to the damper rod, buy them as well.
Buy OEM or "Ariette" (which I think are OEM anyway) seals only - in particular pyramid parts seals are too tight, are a bastard to fit and then cause excessive fork leg stiction.
Personal recommendation - buy OEM (or good copy) gaiters - your fork seals will then last damm near forever and your fork legs don't get dinged by stones.
To free the sliders from the damper rods, if you do not own a "rattle gun" you need around 2.5' of socket extensions to apply a 13mm socket to hold the damper rod while you undo the socket screw in the sliders.
When removing (or refitting) the circlip that holds the fork cap in make or borrow a puller/press to press the fork cap into the fork tube, an donce you have started the circlip coming free, hold a rag over the top of the fork - it is amazing how far that circlip can fly. (And yes we have all done this job wether on our own for with an assistant doing the compression thing, but consider that with a couple of bits of timber and a threaded rod you can do the job safely and with no risk of losing the circlip.
A big tip I only recently discovered myself - when you are putting the fork cap back in, with a nice brand new "O" ring, the little bastard will be tight. The correct lubricant to use to ease "O" rings into place is in fact alcohol (Where I live, Methylated Spirits is the go).
A plastic baby's feed bottle will have graduations on its side sufficient to allow you to accurately measure the fluid quantity and is much, much cheaper than a Burette.
Other will please chime in with anything I forgot.
