Gday you pay gst regardless of what it is.no duty is payable on 2nd hand motorcycles according to my agent.i already have bill of sales for bikes i have bought,with a suitable price on the bill of sale.if you buy a bike for 1000 the gst is payable on the price of the bike landed here,so i dont think it is worth pulling apart a bike you run the chance of loosing bits ,you have to pay someone to pull it apart,you then have to box the parts.customs arnt stupid if you bring a bike in in bits and thet see for example a yz 250 roller than find a yz250 motor they will ask questions as to why-looks like you are trying to rort the system any other questions ring me easier than typing