1F has two speeds and ks, 2F is single speed, so the one in the Victorian museum is 1F. Naming seems counterintuitive! The two units look quite similar from the drive side.
https://www.james-motorcycles.com/wp-content/uploads/2019/05/1954-villiers-mk1f-instructionsbook.pdfLest anyone take museum info too seriously, some comments below.
Leon
1. "The Malvern Star Auto-byke was first introduced after World War II." Prototype in 1940, production models from late 1941.
2. "Malvern Star assembled the machine in Australia using locally-made frames and a variety of imported components including a British-built 98cc single-cylinder Villers Mk. 1 Junior two-stroke engine with a two-speed gearbox." From the prototype until 1950, MS used the Villiers Junior De Luxe, which was single speed. (Not sure of the exact nomenclature, but the Mk 1 Junior was probably the late 1930s verision, with the one-piece cylinder and head, which pre-dated the De Luxe.) The 2-speed Villiers 1F (maybe this is what they mean by "Mk 1"?) was used in 1951, into 1952.
3. "Small had obtained an exclusive Australian licence for these engines in 1945." Interesting, but if true I don't know why Bruce Small Ltd didn't advertise the engines for sale loose. I don't know of anyone else in Australia making autocycles post war, so MS were more-or-less exclusive!
4. "The Museum's Malvern Star Auto-byke was built in about 1948..." All single speed up to and including 1950. My best guess would be 1951, or maybe 1952. Presumably the frame number prefix is 51M or 52M.
5. "... and cost 24 Pounds when new." They were sold Australia wide, and the price varied a bit, but in Melbourne the advertised price in 1951 was 89 pounds.
6. "The Museum also holds an earlier Malvern Star autocycle which incorporates a 49cc French-built Mobylette engine." Interesting claim - they say their other MS was built in Australia from French parts. Not sure, but in their poor photo it looks awfully like a c1950-1 Mobylette AV3 Standard, sold in huge quantities in France and elsewhere. I can find no hint that MS produced autocycles with Mobylette engines, but maybe they toyed with the idea.
7. "In the post-1945 years Malvern Star also sold a diminutive 32cc Berini cycle-motor priced at around 8 Pounds." Indeed they did, from 1951, but the advertised price was 32 gns. fitted free to your bicycle. Not sure where the museum got it's price info!