Ok, I have a 93 softail. I bought it a bunch of years ago and have had my problem since I bought it, but now I finally decided to fix it. I have a PM front master cylinder and a JayBrake 4 piston caliper, the problem is that when the guy I got the bike from bought the stuff, I don't think he matched them up correctly. The front brake has always been harder than hell to squeeze, and it's almost completely useless as far as stopping goes. I know they make different size bores for the master cylinder and the caliper. I'm thinking that he used a master sylinder with too small a bore to make the 4 piston caliper work. I've tried locating part numbers on the master cylinder and the caliper so that I could find out the specs on them, but can't locate any marking other than the brand names. If I remove the brake lines and measure the outlet and inlet holes on both, will that be what the bore sizes are? Anythoughts or suggestions are aprreciated.

 

Usually a bigger piston makes it harder to move. It doesn't have the mechanical advantage that a smaller bore has. The only way to be certain of the bore size is to dismantle the master cylinder and actually measure the piston size.

But in your case I would ask the caliper manufaturer what size master cylinder they recomendfor their brake calipers to work properly. Odds are that a bike made as long ago as yours is may not have the right size on it. In that case your probably going to have to replace them with newer versions. If not aftermarket ones.
Another reason your levers seemhard to move may be that the pistons have gummed up with crap or rust just from age and they need to have the borescleaned out and newpiston seals and or pistons installed.