The Invincible JAP is one of the most recognisable Australian bikes of the 1920s. Unlike many other makes, they were all pretty-much the same! JAP engine (most often the 1000cc twin, sometimes the 770, rarely a single), Burman gearbox, Messenger No. 1 saddle, home-grown Excelsior/Henderson copy forks, Edwards Brothers saddle tanks all attached to a pretty conventional frame supported on 28 x 3 wheels.
Introduced by Turner Brothers in Melbourne in 1922, and sold for the next 5 or 6 years, the Invincible was clearly set up to face the Harley Davidson competition of the day. Advertising was patriotic, with the cap flipped towards the "mother country": "Australia's New Motor Cycle", "It's all British, built in Australia by Australians", "An All-British Achievement in Motorcycle Building", "An Alliance in Motorcycle Making" and so on. None of the at American junk for the Aussie motorcyclist of the 1920s...
I owned, restored and rode an Invincible for many years. A 1923 8hp, it was pretty typical of the breed. Two twistgrips (throttle on the right, ignition on the left), foot clutch, foot brake, hand change, Enots semi-automatic drip feed... plenty to fiddle with while riding but quite a viable machine to rally.
I was once accused of having a love-hate with my Invincible JAP. It was true then, and now that I no longer own it (gone to make way for my 1910 FN) I am not sure the relationship is completely over.
For the "love" part, I still recall certain rides on the Invincible - mostly those "Lawrence of Arabia-esque" ones with the winding road, the wind in the hair and the big twin between the knees. Nothing like a big V-twin in good form.
The "hate" part? Big and heavy really, and the "suicide" (spring-loaded like a car) foot clutch on the right, matched with the only brake under the left foot made stopping on an up-hill gradient a testing experience. Think about it.