This is not quite as big a drop as the massive -9.3% last year, which was the first full-year negative result since the GFC.
Honda was the top brand with 22,735 sales, down 5.9% and a 23.9% market share. Yamaha was second with 21,145 (-1.1%, 22.2% share), Kawasaki (9376, -6.1%, 9.9% share), Suzuki (7557, -6.1% 7.9%) and Harley-Davidson (7019, -21.2%, 7.4%).
Usually the most stable category is road bikes, but they are down 9.%.
Harley-Davidson and Honda tied for leader of the road bikes pack, ahead of Yamaha and Kawasaki.
Husqvarna, Indian, Suzuki and Yamaha all had increased sales in 2018 compared with 2017.
The slump is not contained to motorcycles. New vehicle sales dropped 3%, including a 14.9% drop in December.
Federal Chamber of Automotive Industries (FCAI) Chief Executive Tony Weber blames the automotive slowdown on a slowing housing market, tightening of money lending and the drought.
These effects are being felt throughout the motorcycle industry, but are particularly noticeable in Motorcycle Holdings which owns TeamMoto.