Quite by chance we discovered that the National Motorcycle museum of Australia is just down the road, (by Aussie standards) at Nabiac in NSW. We borrowed a car and headed down the mountain - 30km’s of unsealed road. A further 25km’s towards Sydney and we found the museum, in a tiny village alongside the Pacific Highway. It was huge, 3 halls containing over 400 bikes, from all over the world.

We spent a couple of enjoyable hours wandering around through rows of motorcycles, restored and unrestored, and an amazing amount of memorabilia. Most of the bikes belong to the owner of the place, who has been collecting since he was a teenager, other bikes have been donated and some are on loan to the museum, which until recently was in Canberra.
For anyone making the trip from Sydney to Brissie, I would definitely recommend this as a place to visit.