Ok,i have to replace this fork seal now as it's leaking bad!i know how to get the fork off the bike,i need a step by step replacement info from then on,SO,the fork is off the bike,next please,i want to get it right!!thanks. 
A vise with padded jaws -rubber inserts, soft wood, etc- will be very helpful in securing the fork legs so you can disassemble them without difficulty. Do not crush the legs with heavy pressure... just hold them in a vertical position so they will not rotate.
Remove the drain plug and catch whatever fluid is left in a coffee can or something. There will not be much. I use small 3x5-inch zip bags to keep track of removed parts. Use a Sharpie to write notes on the bag.
Remove the upper rubber plug. Get a helper to push down on the plug using a long-arm Allen wrench, then extract the circlip. Re-read above posts. Remove the aluminum plug and you'll be able to extract the fork spring.
Lift the rubber fork cap off the slider and, for now, push it up the fork leg.
Remove the 6mm Allen screw in the bottom recess of the slider. You may get lucky and not need the socket/extension... yet. The slider can then be pulled off. Note the depth and position of the seal, then gently remove the old seal. protect the alum slider by using a rag to avoid damaging the unit as you pop out the old seal. Use a screwdriver or whatever on the seal. It's toast anyway.
Clean up everything. Flush out the slider with a solvent. Be green. Don't dump the waste chemistry on the weeds. I maintain an oil drain "tank" and periodically drain the junk at the school district's bus barn recycling tank.
Your old seals may have the metric size cast on them. If you don't have the parts on hand, try a local bearing store. Faster than mail order. Also, the rubber slider caps have "felts" inside them. Be sure to replace them as they provide a first line defense against grit. Order from a Beemer supply.
Install seals straight in! A scrap of lumber and a mallet gets it done. Tap them in square to the machine recess. Don't mess this up or the seals will be damaged and you'll get to do it over. Ouch.
Before replacing the fork leg, use a bit of fork oil to lubricate the thin edge on the new seals. Watch the seal's i.d. "lip" to be sure it does not get folded under as you reinstalled the fork leg.
Re-read the above posts regarding the 13mm socket and extension. You may need a helper to hold the damper rod as you torque the lower Allen screw and its new aluminum crush washer. Fit the spring and reinstall the upper cap and circlip. Remember the drain plug. Be gentle on the torque with this little bolt. A new crush washer here is a good idea, too. Leaks are not good.
Fill the forks with fluid through the Allen screw hole in the upper fork cap. I use the spec'd 7.5 Wt BMW fork oil. Some folks prefer 10 Wt. About 230 cc in each leg after a rebuild.
Put the fork legs back on the scooter.
OK, other R65ers. What did I miss on this quickie lesson? Speak up and let's get Beemer back on the road.