Ultrasonic Range Finder with PIC16F690

Hi, I am new to uC and especially range finders. I purchased a SRF04 (SRF04 Technical Documentation) and am trying to interface with my PIC16F690. If I run the code listed nothing happens. If I comment out the while(RB5 == 0) the code will loop and I can at least hear the range finder pulsing. I am not sure if my uC is not sensing the high signal from the echo, or if my code is just wrong, please help! Thanks!

#include <htc.h>
void pause (unsigned short msvalue);
__CONFIG (INTIO & WDTDIS & MCLRDIS & UNPROTECT );
unsigned char ticks = 0; //timer tick storage variable can be 0 to 255
main()
{
ANSEL = 0;
CM1CON0 = 0;
CM2CON0 = 0;
PORTC = 0x00;
TRISC = 0x00;
PORTB = 0x00;
TRISB = 0b00100000;
while(1)
{
/******************Pulse Transmission************************************** ********************/
RB4 = 1; // 10 commands of RB4 = 1 is 10us
RB4 = 1; // pulse high (1 inst cycle per us
RB4 = 1;
RB4 = 1;
RB4 = 1;
RB4 = 1;
RB4 = 1;
RB4 = 1;
RB4 = 1;
RB4 = 1;
RB4 = 0;

/****************Echo Detection***************************************** ***********************/
OPTION = 0b00000101; // Make TMRO prescale 1:64, oscillator = 1 tick per 1us, 64(1us)= 64us. Range = 256(64us) = 16.3ms
T0IF = 0; // Clear timer0 interupt flag
while(RB5 == 0); // Wait for echo pulse to start (go high)
TMR0 = 0; // Start Timer0 with 0 ticks
while(RB5 == 1); // Wait for echo pulse to stop (go low)
ticks = TMR0; // Capture timer0 value and store it in 'ticks'
/****************Display Results******************************************* *********************/
if(TMR0 < 60)
{
RC0 = 1;
RC1 = 0;
RC2 = 0;
RC3 = 0;
}
if(TMR0 > 60 && TMR0 < 120 )
{
RC0 = 1;
RC1 = 1;
RC2 = 0;
RC3 = 0;
}
if(TMR0 > 120 && TMR0 < 180)
{
RC0 = 1;
RC1 = 1;
RC2 = 1;
RC3 = 0;
}
if(TMR0 > 180)
{
RC0 = 1;
RC1 = 1;
RC2 = 1;
RC3 = 1;
}
pause(10); // Pause 10 milliseconds between next measurement
}
}

So I have added timer for pulse input and adjusted my echo timer, my main problem is that I am not detecting an echo signal (RB5 ==1) with my PIC. Any suggestions?