Arvo All...
Found the pics I mentioned...
Attach bolt, end rubber seals and spacer removed
Space cleaned and smeared with H2O resistant grease...in this case it's a Nulon product
Spacer and the 2 rubber seals returned
Gear lever returned. Be careful
not to over tighten the retaining lock nut!
Replace if necessary.
Also, depending on the condition of the connecting linkage ball ends (not illustrated here), they too may need to be removed, inspected, re-lubricated and or replaced. Generally speaking though, they can be easily assessed for unrestricted movement while both it and the lever are still attached to the gear selector on the rear of the gearbox. If, it has to be removed, be aware that early ST1100's may need the linkage re-rigged as they do not have a master spline at the gear box end.
Anyway, if this
and the linkage adjustment
and the components within the gear selector are in good order,
any oil of the recommended viscosity will suffice.
Remember, these motorcycles are getting on now an a LOT of what I consider routine maintenance, has been omitted on most of em!
Cheers, the can :-)