George it could be a couple of simple things ,first you need to remove the black plastic cap on top of the forks. Once you have done this clean up any oil, and compress the forks until you can see where the oil is coming from. It could either be the filler plug in which case, see if it is loose. If it is loose you will need to hold the top plug while you tighten it with an allen key. If it leaks when it is tight, you will need to replace the small copper washers under the filler plug. If it is leaking around the outer edge of the top plug you will need to replace the "O" rings. In order to do this you will have to compress the plug down the fork tube, enough so you can remove the circlip. You can do this a few ways, easiest is to use a two legged puller place legs on either side of the triple clamp and wind down the puller to compress the top plug enough to remove the circlip. The next easiest way is to use a long "T" bar and get a helper to push it down while you remove the circlip. Use a couple of small screwdrivers to do this. Remove the top plug and replace the "O" ring. Replace plug reversing the removal procedure. There are various oil quantities depending on year & model. Just look it up, there are two types of fork Fichtel & Sachs & Showa with different oil levels depending on year & model.
Regards Martin
