Originally Posted by hippiebrian
I was taught that on the street, both brakes or none. Steady pressure on the front vs. a "grab" to avoild lockup. Practice is your friend, as every bike's brakes feel different.
Have you taken a safety course? If not and if they offer them in Guatemala, take one. Otherwise, find an empty lot and purposefully practice locking up the back brake, so you learn and know how it feels. Then practice locking it up and then backing off. Also practice the squeeze of the front brake, and learn how much you can get away with (don't, no matter what, lock up that front brake!)
Here's a little more detail. As you apply the front brake let the weight shift forward, putting more weight on the front wheel while applying the brake increases traction there. This can be done very quickly. After the weight shift the front brake will provide 70 - 90% of your braking force.
Grabbing full front brake before the weight shifts forward can lock the front wheel because it doesn't have enough traction without the weight.
Back brake should always be used with the front. Just have to be sensitive to locking it while you develop your technique.
The thing to know about the back brake is in an emergency stop if you lock it you should keep it locked until you stop. If the back end begins to come around, let it, and ride it out with the brake locked. If the rear brake is released the tire could get traction and this will pitch you into a high side.
When you are moving in a straight line if you feel a momentary locking of either front or back, release and re-apply. As you practice, especially on loose surfaces, this will happen more often and will become an automatic response.
It sounds like you are very interested in understanding braking and improving technique. Attitude is the biggest part of constant improvement.