Simple LED driving issue - setup?

I'm trying to drive six LEDs as an indicator, but cannot figure out quite what I'm doing wrong. If I use this as my code:

portb = %1
pause 100
portb = %10
pause 100
portb = %100
pause 100
portb = %1000
pause 100
portb = %10000
pause 100
portb = %100000
pause 100
portb = 0

Leds on PORTB.1 & B.2 do not light, all the others light as they should, however if I use the following as my code B.1 & B.2 light up as they should

portb = %1
pause 100
portb = %11
pause 100
portb = %111
pause 100
portb = %1111
pause 100
portb = %11111
pause 100
portb = %111111
pause 100
portb = 0

Any thoughts - I have come across this issue before and never managed to get it sorted so clearing it up would be great. Any help greatly appreciated. The PIC is a PIC16F722 and my setup is as follows:

@ __config _CONFIG1, _INTRC_OSC_NOCLKOUT & _WDT_ON & _CP_OFF & _MCLRE_OFF & _BOR_OFF

define osc 4

'****************
' Hardware Setup
'****************
ADCON0 = 0
ANSELA = 0
ANSELB = 0
OSCCON = %00010000 '4MHz
CPSCON0 = 0 'Capacitive sensing off
PORTA = %10000000
TRISA = %01000001
PORTB = %00000000
TRISB = %11000000
PORTC = %10000100
TRISC = %10000000

It is probably a read-modify-write issue.

Try -

TRISB = $FF
PORTB= $FF

TRISB.0 = %11111110
Pause 100
TRISB.0 = %11111101
Pause 100
TRISB.0 = %11111011
Pause 100
TRISB.0 = %11110111


...

Thanks Charles, My bad sorry - one of those pesky solder bridges your code helped me find the problem tho.

Sorry for posting this when it was a silly wiring fault on my part