I know this is an old topic, but I just saw it (looking for opinions on hydraulic clutch levers) and I *hate* to see confused physics go unanswered! ;-)
Basically, MotulMonsta is right. DUNEDEMON is right in places. Sure, if you increase the distance between the fulcrum and where you're applying the force (say, by using a larger jack handle), you can apply a greater force to the load. But we're not increasing the length of the clutch lever, so that comparison doesn't apply in this case.
By the same token if we *shorten* the distance between the fulcrum and the load (say by shortening the distance between the pivot point and the "pick up point" of the cable), we can also increase the force applied to the load. Either way, we're increasing the "lever ratio". If you move the "pick up point" *further* from the pivot point as DUNEDEMON was arguing, you are lessening the ratio and decreasing the effect of the applied force, i.e. making the clutch lever more difficult to pull.
So, when you use an ez-pull lever, the cable moves a shorter distance for a given amount of clutch pull. Look at it this way - you're applying a Force over a Distance for a total amount of Work. That amount is how much work is required to disengage your clutch. The distance is pretty much constant - the distance from your clutch lever to your handlebars. Then you get an ez-pull lever. Now you're applying a lesser force over that same distance. It still takes the same force to push your clutch plate against your clutch springs, so less total work means your clutch plate (and cable) moves a smaller distance. So your clutch is less disengaged than it was before which may be why some people complain about ez-pull clutch levers. Doesn't mean you can't adjust the lever to make it work...just pointing out facts.
There, now that everyone is my work here is done. I feel better.
p.s. DUNEDEMON, I think what MotulMonsta meant by saying you're moving the pivot point in your jack example is that the pivot point moves *relative to the force and load*.