The Australian-made Invincible J.A.P.
With Phil Aynsley
An Australian motorcycle that was promoted as being “An All-British Achievement in Motorcycle Building”. Times have changed!
The Turner Brothers dealership in Swanston St. Melbourne lost their Harley-Davidson agency in 1922 and were in need of a large capacity motorcycle to sell – enter the Invincible Jap.
The bikes were constructed by Firth Bros. in Richmond for the Turners and used a mixture of British and locally manufactured parts.
A range of three JAP motors were available – a 990 cc 8 hp V-twin, a 770 cc 6 hp V-twin and a rarer single.
Other imported components were the Burman gearbox, Messinger seat, Thompson & Bennet magneto (or later a Bosch) and a Cox Atmos or Schebler carburettor.
The frame, Excelsior/Henderson copy forks, mud-guards, pedals, rack and tank were all made in Melbourne.
While the bike was announced in 1922, the first examples weren’t available until the following year, and production (thought to total around 350 machines) ended in 1925, although a few bikes were still being sold up until the 1930s.
The Invincible JAP remained mostly unchanged during its life, although several updates were made it try and keep it competitive.
The wheels were changed from 28 x 3.00 inch to 26 x 3.00 inch in 1925, and the original tank-mounted Enots oil pump was replaced by a Best & Loyd unit.
The bike I photographed is a 1923 770 cc model and is fitted with carbide lighting.
Later, bikes used electrics. It is also one of the four bikes featured in the Vintage Motorcycle stamp series released in 2018 by Australia Post, illustrated by Mike Harbar.
Invincible JAP Specifications
| Invincible JAP Specifications | |
| Engine | 770 cc 6 hp V-twin |
| Transmission | Burman gearbox, three-speed |
| Fueling | Cox Atmos or Schebler carburettor |
| Frame | Reynolds Steel Tubing |
| Suspension | Excelsior/Henderson copy forks |
| Wheels | 28 x 3.00 inch, 26 x 3.00 inch |
