How about

tach = (b1*100)+(b2*10)+b3


Why are you speciying the digits individually ?

Whats wrong with....

tach = 135 'or whatever

LCDout DEC tach ' which would suppress leading zeros eg 135 or 79 or 4

LCDout DEC3 tach ' which would always display 3 digits. eg 135 or 079 or 004