An oil question, but not That one!

[The Grey One]

I'm in the middle of a bit of winter tinkering on the GS. The fork bridge was showing the usual signs of the effects of the elements. So strip it down to gain access,wheel off, front mudguard and forks out. Bridge nicely repainted in Hammerite, why not do the fork bottoms to match? I have managed to spill a whole load of fork oil because of stupidity.

My question is what is the oil, the workshop manual helpfully says "BMW hydraulic fork oil" Does anyone know just what oil grade is required? and does it matter given that it is just a lubricant? Given the amount lost, ie most of one leg full I think I should just change the oil in both forks. Anyone know?

And a couple of photos, see if you can work out how the oil got spilled

 

[Cortina]

Does not matter much , since it has exactly ZERO affect on the damping .. I would just use a standard ATF or whatever I had sitting about (light rather than heavy)

 

[pegs]

Change the oil its cheep and probably half water by now any way. mine was orrible when I changed leaky seal mind you 18 years 100000 miles +

 

[pegs]

forgot to say I used light fork oil