The parking brake won't affect the lever on the yoke. Meaning if the parking brake is on, it won't make the lever on the yoke not retract. I would look inside the yoke as Hoodlum said. One thing to note is that it the best adjustment for the cables from the yoke to the master cylinder is to have a little pre-load on them. When I first worked on an FL350R, I set my cables up like a clutch cable on a bike with a little play in them. I set them up so the plungers are pressed down a little and get better braking.