S.A.F.U.
Newspaper reports of S.A. registrations:
George Albert Laver, Mizpah avenue, Unley, 2 1/2 S.A.F.U. ~ 31 January 1917.
H, L. Goldsmith, Edithburgh, 2 3/4 S.A.F.U. ~ The Register, Feb 18th 1920
N.B. SAFU = South Australian Farmers' Union.
Source: Trove NLA
Sampson
Leon Mitchel writes "Sampson's, 108 Pulteney Street in Adelaide c.1921."
Results from Trove:
1. 1920 Sampson's 158 Rundle St sold motorcycle tyres, accessories etc, but no Samson or other brand of MC mentioned.
2. 1924 Sampsons sold bicycles, 164-166 Pulteney St.
Sources: Leon Mitchel, Trove NLA.
Sarich Orbital Engines (W.A.)
Silver Star
Manufactured from 1905 to 1907 using Minerva engines.
Source: OTTW
Sirdar
Sirdar marques (possibly SIRDAR) are listed as produced in 1914 South Yarra, Melbourne, and also in 1915 in Westbury Tasmania. Westbury at the time would have been a very small village.
Sources: OTTW, Simon Fleming, et al
Sol Invictus
Assembled in Alexandria NSW using mainly Chinese components. The firm began production in 2007.
92 McEvoy Street Alexandria NSW
101 Hunter St Newcastle
Source: Wikipedia
Solar (NZ)
It seems likely that Solar NZ rebranded Sun motorcycles. See Sun Motorcycles
Southern Cross NSW
Sovereign Tas.
Speedway
South Australian registry records for January 1920 mention "15857. S. W. Grabia, Yorketown, 2¼ Speedway."
There is no other mention in the press of such a marque, and it does not appear in Saward.
In Jan 1917 an article reads, "A young man named Grabia proceeded on a motor cycle to Yorketown (nine miles distant) for medical aid. Dr. Russell was soon on the scene, and found that Baker had sustained an injury to the spine."
Source: Trove NLA
Sporton
Manufactured by Peter Gardiner Enterprises Pty Ltd, Old Cleveland Road Capalaba.
The firm also built RTV engines, and is involved in aviation. Peter flies a Yak-52.
The Sporton housed a Harley-Davidson Sportster engine in a Norton Featherbed Wideline frame, available as a kit for AUD$5000, or as a complete machine for just under $20k.
Sources: ozebook.com, et al
Stolford
Edwin Ebenezer Odd and his son Edwin, from Ryde, were exhibiting their Stolford motor bicycles in 1902.
Entrants in the Dunlop Reliability Motor Contest from Sydney to Melbourne
F. Odd. N.S.W. (3½ h.p. Stolford)
Table Talk (Melbourne, Vic.) Thu 16 Feb 1905
Sources: Jenny Fawbert via VMCC NSW; Trove NLA.
Sunlight
R.J. Dean of Dean's Motor Garage in Breadalbane, Launceston is listed in Saward in relation to the Sunlight motorcycle. The brand does not appear in any of the newspapers of the day.
FOR SALE
DEAN'S Motor Garage.— For sale, owner leaving State: 2 Buick cars, 1 new 5-6 H.P. Motor Cycle, 1 Douglas Motor; also number of second hand cycles, thoroughly renovated. Large quantity of motor cycle accessories, to be sold at cost. 25 cases benzine, at 21/6 per case; motor oils and greases, etc., etc.
Call or write particulars R. J. DEAN, Breadalbane.
Daily Telegraph (Launceston, Tas.) Sat 9 Sep 1916
Source: Trove, et al
Rarer Australian Marques