Racer X is probably right on the money for barely used HD shocks. I run Ikons but they are a pricier option.
Go for straight rate springs in the forks though, matched to you weight/use. There's only 100mm/4" travel in the 650's forks. With correct sag, that only leaves about 2" max up or down, which gets easily eaten up by average road imperfections. Progressive springs will give up too much travel to your weight alone, IMO.
As for fork oil, try 5W. Thicker oil (10W or even 15W) will slow the compression stroke, making weak springs feel stronger. BUT compression is only half the story, for bumps that raise above the road surface. There are also holes and dips too, that the forks/wheel need to dip into (rebound!) to keep you stable.
So a proper set of springs will control your compression/sag properly. 5w oil won't interfere too much with the stiffer spring absorbing energy as it compresses. That's okay. What the 5w does do is speed up the rebound, allowing the forks/wheel to follow the dips better as they extend. The 650's forks are simple damping rods, with a single rebound refill hole that impedes thicker oils.
I have tested 15w, 10w and 5w (Motul brand) with upgraded springs and Racetech GVE and I've almost got the Big Burger dancing. Just a touch more slow speed compression damping and I think that's it.
As always, I bow to the experience of Le Dude, Cliffy, Buffalo (and others) on this subject, but the above really worked for me.
