If the motor with a slipper clutch will make the rear wheel slide, the rear brake isn't going to do shit. Motorcycles, and brake technology have moved on since 1986. ...and if the bike doesn't have ABS odds are that you are more likely to high side yourself than stop in a controled manner, seen that over and over. If the bike does have ABS it doesn't really matter as you can't really get yourself in to much trouble, but its just bandwidth you are waisting things that could be savign you like evasion. Most of the touring/sport-touring bikes have linked brakes anyway.