Brassballz

Hi all, Newly registered but Ive been reading threads here for a long time. I need a bit of advice. I have an L28 motor with twin Hitachi round top carbs. Ive been told by a mechanic they're in need of a rebuild but Ive tried a couple of places around Brisbane and they've politely told me to move on, it's too much trouble finding parts etc. Does anyone know a shop that'll do the work? Even in another state if you know a good company there. Thanks in advance.