I had a rapide here a year or so ago, recommisioning for sale and the thing had terrible brakes on the front end, pull them hard and they didn't go to the bar but were virtually non effective. It had some long home made arms on the front, the serrations having been cut by hand with a hacksaw, so I set about redoing everything. Now this was a bike that the owner had for many many years, even came to California on it for the 1991 international, but always seemed a little reluctant to ride it. Usually took his '73 Z1 900 or a later Yamaha. I guess he was too proud to ask for help.
About 1/2 way on the pull of the lever the outer cover of the lower 1/2 of the primary cable jammed between the arm and the balance beam. Of course the longer arms requiring more travel did not help the situation. Took about 3/4 inch off the outer, put new short arms on the front and after 30 years it finally had some real brakes!