Originally Posted by machinebuilder
How did you decide where to put it?
This setting (setting rider sag) does affect the steering geometry.
Think of the bike pivoting on the front wheel, if you raise or lower the rear of the bike (by adjusting your preload) you are changing the angle of the forks. If you get things at a bad spot it will be unstable.
The owners manual has a procedure for setting your preload.
I found this out when I rode a KLR, they are severely undersprung for a 200lb person + camping gear. The headshake scared the crap out of me.
I will search for some tutorials and see what I can do about it
This one is for ST, but can have a look: