Rear brake on a stock bike
With only the rear brake being used on a stock bike, this is a key tuning aid and can make the difference between finishing in one piece or falling off all the time.
This of course assumes that on a warm, dry track with plenty of grip your stock bike will brake in a straight line using 100% brakes without spitting you off!
What I tend to do is adjust the brake to work well at the slowest or slipperiest braking point on a track, and adjust the braking distance to suit on the faster sections of track.
By adjusting the brake down to prevent locking on the slower sections, it’s possible to get a consistent run without crashing off every time you hit the brake. It may mean you have get off the gas a little earlier for some corners, but for me it’s better to lose a tenth or two in early braking than several seconds by having a crash…
Again, ask me how I know this…