new member

Hi, I'm Steve.  I'm new to this group.  I am currently restoring a 1978 KZ650b. I have a few questions on the front brake calipers.  The pads won't retract enough to insert the disc when reinstalling the wheel.  How do I get the caliper to retract further to install the wheel with the disc?  I need them to open about a quarter inch more.  I bled the brakes and the two holes in the reservoir look clear.  Any thoughts or suggestions?

I've attached a picture of the project.   

Welcome from the UK. Are these "single" piston callipers ? if so are the "sliders" free ?