I have a 2002 marathon sl (I think, previous owner took the decals off) on my bike and I am going crazy trying to figure out exactly how it works: I have read the manual on the site but from going to the manual to actually being able to figure out exactly how to make it do what I want there is a heck of a difference...

Supposedly it has this ECC5 cartridge that has 5 positions for the rebound damping, then I have 3 ports I can inflate with my mini-pump, according to the manual I think they are two compression damping (side port, both legs) and one again for rebound damping (center port on left leg).

Obviously the two left/right compression damping are easy to figure out (more air pressure = fork is harder to push down), but I can't for the life of me figure out how to set the rebound damping and, most important, why I would have an air port and a clicky wheel to set (theoretically) the same thing.

Anybody could give me a hand? thanks.