G'day Mate,
You don't need to remove the fuel tubing to set the low end mixture, just run it up to full revs, & get it well warmed up, then throttle down to idle, & CAREFULLY, squeeze off the fuel tube to the carby, you can use fingers or forceps to squeeze the tube, & listen to the motor, if it picks up a lot of revs, before slowing, it is rich, so lean it about 1/8th of a turn, turn it in (clockwise). If it just stops, it is too lean, & the reverse applies. It should just increase a few revs, before slowing, then it is perfect. Be aware that if it is rich, & you lean it a bit, you will need to reduce your idle speed because it will probably speed up a bit at idle.