You set your motor power for the arm and fork equal to the button values. When you press the button, the button value changes from 0 to 1. The maximum power for motors is 127, not 1. So the motors run with practically no power. The correct way to program buttons is to use an if-statement. Try something like this:
motor[brightarmMotor] = 127;
motor[brightarmMotor] = -127;
motor[brightarmmotor] = 0;
//127 is full motor power, instead of 1.
And you can copy-paste that to the other buttons and motors. Also, I would reccomend that you set your arm/fork motors to the same button instead of a different button for each motor.
Edited for specificity.