It appears b1yel1 is a pin number not a LOW/HIGH value, so the if statement will fail on any pin number that isn't 1 and skip line 7
5 digitalWrite(b1yel1, HIGH); // I have put this line in to prove b1yel1 is high
6 if (b1yel1 == HIGH)
7 digitalWrite(b1yel2, HIGH);
You could check the pin is high, but you just set it high, so only an interrupt could change it, which you probably aren't using.