I've never heard of a motorcycle being crated for air freight, unless it was being transported by a smaller single-aisle aircraft such as a B737 or A320, in which the cargo hold is not tall enough to accept a fully assembled motorcycle.

All aircraft used on routes between Australia and North America are twin-aisle (in other words, widebody aircraft), and they all have sufficient height in the cargo area to accept a fully assembled motorcycle - heck, you don't even have to lower the windshield.

The normal practice for shipping motos from Canada to Europe and vice-versa is to just throw them in a ULD (Uniform Load Device) - ride it in, ride it out. A ULD large enough to hold a full-size motorcycle - such as a LD-6, pictured below - has a weight capacity of 7,000 pounds. A single large motorcycle weighs about one-tenth of that. So, the trick is to find a carrier who is operating on routes where the aircraft is very close to maximum gross weight because they are carrying a lot of fuel, and has empty space down below in the cargo hold, and needs to repatriate some of their empty ULDs back to home base. If you find such a carrier, for them, tossing a motorcycle (or two) into an otherwise empty ULD is "money for nothing", because the motorcycles weigh so little.

You might want to do some research and see if there are any 'charter' or lesser known (such as low cost operators) air carriers flying between Oz and North America. Those carriers typically always hit gross weight and have lots of space left over down below - especially on long routes such as Oz to North America.

I'm amazed that the Australian company quotes AUD $4,000 for a single motorcyce. Shipping my Honda ST 1100 from Canada to Europe costs me about AUD $1,500. The airlines don't even ask the weight of the motorcycle when you ask for a quote.

Two motorcycles can fit into a LD-6 ('Lower Deck 6) ULD, no problem.

So - maybe go shopping around, ask air carriers operating from North America to Oz what they would charge for a couple of motos in an LD-6. Rates will vary dramatically depending on time of year - so if you are not in a hurry to get the moto, let the air carriers know it doesn't matter what month it gets shipped in.

There is information about the "Dangerous Goods" aspect of shipping motorcycles by air at this post: Rules for shipping motorcycles by air freight. I made that post in 2006, but the rules have not changed substantially since then. Just show up with less than 1/4 of a tank of fuel. No need to disconnect the battery or do any other kind of disassembly. Be aware that the air carriers don't like it when there is stuff in the panniers other than perhaps a helmet and a tool kit - for them, that complicates things.

Michael

My motorcycle, in a LD-6 for shipping Canada to Europe