[ttm21]

I am just a casual rider on small trails. The rear is riding very stiff. I need to know if anyone has any advise on how to make the rear suspension weaker.

[the hawk]

set your sag

[[email protected]]

You do need to set your sag, but you need to figure out if your springs are appropriate for your weight or not.
How much do you weigh ? If you weigh over about 150 then it's stiff because your weight is collapsing the spring, causing you to ride in the stiff part of the spring.
If so softening up the rear pre-load(your manual describes the procedure) will actually make the rear even stiffer. If you are over that weight then you need stiffer springs.
BBR makes what they call "adult" or HD front and rear springs, I highly recommend them and you can buy them right here.
The front if you add 10cc's of the recommended 10 wt. fork oil along with the heavier springs will be improved considerably.
Then, set your sag. Doug