suspenders
 

Now I know this has been covered before someplace but I guess I'm just feeling lazy (well short on time really).

At 12,000 miles I know the ST2 wants new fork oil, but I'm wondering if that would cure the 'pogo stick' effect I'm getting. This basically up to 40 mph on not the best of roads, accompanied by that very uncomfortable lurching effect felt in the stomach , at 50-60 (and above) mph everything is fine.

Are there any reccomendations for the kind of oil to fill the forks with ? Also the setup is still factory spec and I know most people feel this is not perfect so any tips there would be appreciated.
NB while I am mechanically/technically minded I just switch off with jargon and hence don't know my rebound adjuster from my elbow.. so please keep instructions idiot proof :)