the rear brake as you have it has ''bump brake'' that is every time the suspension moves so does the brake pedal.it would be very noticable with nice compliant shocks sprung correctly.the way you have it you cannot have a positive up stop that is adjastable at the brake pedal itself.if you did and tried to adjust it like a well set up brake pedal that is ready at your toe in the best location and minimal free travel in the pedal,well hitting a big enough dip in the rode or bump puts on the brake for you.so you are stuck with a pedal that floats around wherever it wants and moves noticably on bumps.to alleviate the deal the actuation point on the rod needs to be very close to the swingarm pivot..much as the stock pedal shaft and actuation arm was.a linkage rod from pedal to a greatly shortened stock pedal is the best way,really as it also incorps return spring and adjuastable up stop thataway,.another setup that is lighter but in my ho has less feel is a sheathed cable ,basically lashed-up like a front brake cable, that is cable housing stayed at both ends