[Tommy]

I'm trying to be helpful, but I'm not sure you are speaking of the clutch master cylinder. ASSUMING you are, and that it drives a slave cylinder that moves a clutch fork, here is some info that may help. The amount of movement of the clutch fork end (where the piston from the slave cylinder engages it) is related to movement of the clutch pedal by the following formula.

t = D x D x T / d x d
where:
t = lenght of movement of the slave cylinder piston
D = diameter of the master cylinder
T = length of movement of the master cylinder piston when the pedal is depressed
d = diameter of the slave clyinder

To get T, I'd need to know how your clutch pedal is configured (e.g., distances from pivot to pedal, pivot to piston mount, pedal movement before engagement, full pedal travel and position of the pivot relative to the MC piston end).