I can't over-emphasize the importance of not running your chain too tight. AND, if you are used to adjusting your chain by sight/feel and haven't done this procedure yet, you are in for a surprise at how much slack these bikes need. Running your chain too tight loosens the sprocket bolts, prematurely wears (or breaks) the chain and sprockets, beats up on the transmission and wheel bearings and makes your suspension bind up!

Put the bike on a stand, far enough forward that the rear wheel is suspended. Unbolt and remove the shock. Cycle the suspension through its entire stroke while feeling the chain slack. When properly adjusted it should have a little slack even at it's tightest point, around 1/2 stroke.

For the above right picture, I have removed the shock and I am holding the rear suspension off the floor with my foot while taking the picture. That is about the tightest point in my suspension travel, and I have set it so the chain just starts to go taught there. The picture to the left shows the amount of chain slack with the shock re-installed and the suspension topped out. Yes, the chain makes a commotion when it is this loose, especially on a thumper, but at half-travel it still goes tight.